Just عadly

Qt Performance Tips

2012-02-25T14:57:00.000+02:00

As I've been moving away from Qt, I thought I should write some notes about things I've been taking care of when writing a Qt application. Even if they are not the super-duper tips , they may be useful for some people out there.

These tips, and more you may know or apply by default, can make a huge impact on your application. As I remember, the right compination of these tips has helped me to reduce the time of a big operation, and I was shocked by numbers. Imagine a process that takes 7 milliseconds and a smooth UX instead of 10~30 seconds and a laggy UX!

1- QCoreApplication::processEvents
When getting inside a long loop (for or while loop) the application will freeze because of the intensive resource consumption, so it is advised to process events inside the loops to allow other thread to run. You will notice the difference if, for example, you have a progress bar and you update it from inside the loop. The progress bar UI will not be updated eventhough its values have been set, because the loop is not giving the chance for other processes to work. A line like the following can do the job:

qApp->processEvents();

2- Timer slots instead of threads
Sometimes you want to make a non-blocking process inside your application, so you make another thread, then may get in the hastle of communication with the current thread or modifying the UI. An example I saw and liked was as follows:

QTimer::singleShot(0, this, SLOT(doSomething()));

It was used in a GUI application when there was much code to write in the constructor, and the code was making much delay in the appearence of the main window. So the solution was to move this code to a slot with zero timeout.
Another usage was when querying much data from a database, showing the results of the query simultiniously in the UI (e.g. filling a datasheet line by line) instead of waiting for the query to finish had a great impact on both performance and user experience.

3- QCache
One of the tasks I hate in my application is accessing a database or filesystem. So using the QCache class in my application could minimize the time of accessing a file or database. If you know how computer cache memory works on hardware level you will get the idea. When I query some data from database, I save them in QCache. So the next time I need the data, I look for it inside my cache member before going to the database. If I find it, I use it. I don't find it, I go to the database. This can help boosting the performance if you have an intensive usage of your database or filesystem in runtime (like a game data maybe or history suggestions). So what it the advantage of QCache over QMap or other classes? Here is a quote from the documentation:

When inserting an object into the cache, you can specify a cost, which should bear some approximate relationship to the amount of memory taken by the object. When the sum of all objects' costs (totalCost()) exceeds the cache's limit (maxCost()), QCache starts deleting objects in the cache to keep under the limit, starting with less recently accessed objects.

4- Qt Resource System
"The Qt resource system is a platform-independent mechanism for storing binary files in the application's executable". But it is not always the best choice when you have a lot of files. Remember that this increases the size of your executable, and memory usage. So when you have files that can be placed beside the app instead of beig inside it, this will make less memory usage, leaving more momory for later computations, especially when you have limited hardware resources. Keep the resource system for a minimal number of basic resources like, as the documantation says, a certain set of files (icons, translation files, etc.) that you don't want to run the risk of losing them.

5- Painting
When you paint some graphics inside the application, whether for a game or just a background, it is advisable to take care of the following.
a) You do not always need to repaint all the space. Sometimes, for example, you want to update a logo at the center of your window or splash screen, then why repainting hundreds of thousands of pixels when you only want to repaint a 64x64 rectangle in the middle?
b) When you repaint the same image over and over (for example, a background in the update() method), it is useless to load the image every time in a temporary variable inside the method because loading takes time. It is better to declare a local variable in your header file and load it once (in the constructor or anywhere when needed) then only repaint it without reloading the same image.

6- Database indexing
This may not be a Qt-specific tip, but it is still very important when you have a database of tables of 500,000 entries.

A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of slower writes and increased storage space. [Wikipedia]

If you do not know about this topic, I suggest you spent an hour reading and applying it on any database to notice the difference it makes.

7- You application in idle state
Some application features are only useful when the user is looking at them. For example when you are retrieving weather conditions from a remote server. What is the benefit of downloading an XML file, parsing, and updating your UI every couple of minutes when the user is not even looking? When the user is in a state when he does not benefit from a feature, it is better to stop/pause it.

So ... these were the performance tips I had in mind till now. I hope you learned something new from them.

Book Review: Google SketchUp for Game Design: Beginner's Guide

2012-01-17T21:36:00.000+02:00

Today I'm writing a review on a very special book: Google SketchUp for Game Design: Beginner's Guide, by Robin de Jongh, Packt Publishing. I really enjoyed this book, and to be clear and organized, I'll write my review as definite points (as usual =) ).

Pros:

As the book title mentioned, it is a guide for game design and beginners. So the book did not only go from bottom up in Google SketchUp, but also went to explain the basics of other applications that can get involved in the game design process like GIMP, and even introduced one of the best game engines: Unity.
All tools and websites introduced are free, or have trial versions/accounts.
The book author stressed on a very important thing: honesty, and the cover image is an example of this honesty. Because what you see on this cover is what you get and can do yourself using what you learned in Google SketchUp.
The way the author explains is not boring or lengthy. But on the contrary, it was very smooth, interesting, and straight to the point.
The author stressed on introducing the basic and important features of each applications without getting deep, which I considered it a very nice method in dealing with a beginner in any application. Beside some tips and tricks, and notes on how bigger companies do this work and manage such tasks.
The book in general was like a quick tour in the world of assets and game design, opening some doors I might not see if I just go to learn Google SketchUp alone.

Cons:

The websites and links provided inside the book were not all working. Some links were removed and some had different sub-directories, but somehow I managed to get to most of them by a quick search.
The author sometimes missed some small details that -for a lazy beginner- can be crucial to get a step done. Some small details like the order of marking objects or how to use a certain tool. But the athor has indicated that this book needs some work, so there is no place for laziness.

All in all, I would recommend this book for reading, whether you are using Google SketchUp for game asset design, game level design, or even as an architect.

MeeGo 1.2 for Netbooks in Virtualbox ( Windows and Ubuntu )

2011-11-05T23:59:00.001+02:00

These are the steps for installing MeeGo 1.2 for Netbooks in Virtualbox. These steps were tested on Ubuntu 10.04 and Windows 7. Steps are the same on both OSs, and screenshots were taken from Ubuntu 10.04.

First, you should download the latest version of MeeGo from: https://meego.com/downloads
and install Virtualbox, whether from : https://www.virtualbox.org/wiki/Downloads or from Ubuntu Software Center.

Second, covert the extension from the downloaded MeeGo image from (*.img) to (*iso).

Then, open Virtualbox and create a new machine.

Make sure you indicate the machine as a Fedora Linux version, with Ram 512MB or higher (MeeGo Wiki says 1GB) and at least 5GB of disk space. Also make sure you enable the options of "Enable PAE/NX" and "Enable 3D Acceleration".

Here are screenshots of this step:

Now let's start our new virtual machine. From the menu appearing, chose "Installation Only", wait until some operations end, then the UI wizard will appear. The steps of installation are almost straight forward. And after installation, A message will say that you should not remove the USB stick (or the virtual CD ROM in our case) until you press the "Close" button. So press "Close" and then un-mount the CD ROM from the Virtualbox menu: Machine -> CD/DVD Devices -> Unmount. Then reboot the machine from: Machine -> Reset.

After restarting, the wizard will continue with some basic settings. When going through these steps, they went fine on Windows 7, but on Ubuntu 10.04 I had to reset the machine a couple of times to finish the settings steps and move to the next step. BTW: The blue splash screen at the beginning of these steps may stay for a few seconds.

Now we come to a little dirty part. At this moment, the machine may start normally without any effort. But some other times you need to do the following steps. These steps are the best I could write after searching and trying for hours:

First wait until the first blue screen appears and press "ESC" on the keyboard. This will view a list with one option to boot MeeGo. Press "Tab" key to edit the command of launching MeeGo, remove the last part of "quite vga=current" and replace it with "init 3" then hit the "Enter" key.

Some commands will appear quickly on the screen, wait until you see the login screen.

Do a login with the username/password you have set in the previous steps. Then write:
sudo su
[enter the password again]
chmod +s /usr/bin/Xorg
uxlaunch

Now you should wait for a few seconds to see the MeeGo home screen appearing.

If you want to shutdown the machine in a legal way, you will notice that there is no "Shutdown" button. But you can still choose "Machine -> ACPI Shutdown" from the virtual machine menubar.

There is another final note: Although I had to write the terminal commands whenever I launch the machine on Windows 7, I found the machine booting normally on Ubuntu 10.04 once I hit the "Start" button.
Update: It booted fine on both OSs. The problem was because I did not make a legal shutdown, so the session was not saved.

Read/Edit Phone Contacts Using Qt

2011-10-12T15:16:00.000+02:00

Here I'm posting a code snippet I used to modify my contacts on both SIM card and phone memory. What this code does is that it loops over all available memories on phone and edits each number according to a criteria I set. To simplify the code, I removed the business parts and posted only the parts related to Qt Framework and the loop over the contacts.

The skeleton of the process is as follows:

Get all available manager on device. In my case they where "symbian" (i.e: phone memory) and "symbiansim" (i.e: SIM card)
Loop over the list of managers.
For each manager, get the ids of available contacts.
For each contact id, get all the available phone numbers.
For each phone number, decide if it needs to be changed (the business part), or just output the number or use it however you want.
A couple of flags are set to save any changes in a number/contact

[*.pro]

symbian:TARGET.CAPABILITY += ReadUserData WriteUserData

CONFIG += mobility
MOBILITY += contacts

[*.h]

#include <QContactManager>
#include <QContact>
#include <QContactPhoneNumber>

QTM_USE_NAMESPACE

[*.cpp]

//find all the available mamagers on device
QStringList managers = QContactManager::availableManagers();

//loop on all the available managers
for(int m=0; m<managers.length(); m++)
{
    //initialize a new contact manager with one of the ids in "mamagers" list
    QContactManager cManager(managers.at(m));

    QList<QContactLocalId> idsList = cManager.contactIds();
    
    //loop on all the available contacts
    for(int i=0; i<idsList.length(); i++)
    {
        QContact contact = cManager.contact(idsList.at(i));
        bool contactEdited = false;
        
        //get all contact details the can be considered a phone numbers (mobile, home .. etc)
        QList<QContactPhoneNumber> phoneNumbers = contact.details<QContactPhoneNumber>();

        //iterate on the phone numbers of the contact
        for(int idx=0; idx<phoneNumbers.length(); idx++)
        {
            QContactPhoneNumber phone = phoneNumbers.at(idx);
            QString number = phone.value(QContactPhoneNumber::FieldNumber);
            bool numberEdited = false;

            // ################### Editing Zone #################
            
            // here you put any operations related to editing the number
            // and set the "edited" flag to true if you changed the number
            
            // ##################################################

            //if the number is edited, save it in the "contact" object
            if(numberEdited)
            {
                phone.setNumber(number);
                contact.saveDetail(&phone);
                
                //raise the contactEdited flag to save the contact later
                contactEdited = true;
            }
        } // end of numbers loop

        if(contactEdited)
        {
            //save the edited contact
            cManager.saveContact(&contact);
        }
    } // end of contacts loop
} // end of managers loop

Here are some notes about this code:
- If you need to interact with one manager, just pass one item to the "managers" list, or simply remove the managers loop.and set the manager manually.

QContactManager cManager("symbiansim");

- It is a good practice to not freeze the application with all these nested loops. So if you are sure that no other event can cause a problem while executing these operations, you can insert this line inside each loop.

qApp->processEvents();

- Self-signing is enough to get this code running on a Symbian device.

Book Review: Play Framework Cookbook

2011-09-21T21:48:00.000+02:00

Ok, after some reading in parts of the book and touring some other parts (remember my previous entry?), here are my notes about this book. But first I have to mention the beckground I come from:
- Basically I come from a front-end development environment.
- C++ is my main interest, then comes Java.
- I've just started to learn Play framework and found it interesting to go deeper into.

Now let's get to the review:

1- From the book intro, the author indicated that proceeding with a Play tutorial plus some web developer skills—HTML and JavaScript. So I thought it would not be that hard to get started, and it wasn't at the very beginning, then it accelerated very quickly that I had to skip more parts chapter after chapter. Maybe I needed more that some knowledge or skills, I needed the "web culture".

2- I liked how the examples were introduced along with test cases. Examples on the internet may settle with some code and leave the testing to the user, so the book made it more professional.

3- Some code parts seemed to be eligible to be put inside real projects, not just dummy examples. They were well designed.

4- Most of the times I notice how the author tends to to stop at some part of the explanation or move faster. So I sometimes had the feeling that parts of the book were more like highlights.

5- This book can be useful as a reference while coding or preparing materials for a course/project. But not a solid tutorial to take (remember my background, it is still useful as I mentioned).

To Read: Play Framework Cookbook

2011-09-08T20:34:00.000+02:00

Today I had the opportunity to receive a softcopy of a new book: Play Framework Cookbook , by Alexander Reelsen, Packt Publishing.

And since Play Framework has not so many books to find, It was a good opportunity I cannot miss. What is attractive in this book? From the first look, it does not require deep experience with Play Framework. You just need to follow a couple of examples ( link1 , link2 ) on the internet to be ready for this book which already explains some basics in the first chapter and promises to mention some basic throughout the book.

Now let me start reading and give my review. If you are in a hurry to see the book from inside, here is a link to a sample chapter: (download)

Stay tuned ...

Play Framework Tutorial

2011-07-08T23:35:00.000+02:00

A couple of weeks ago, I attended a introductory one-hour session about Play Framework. And it was interesting as it was my first time to experience anything related to the web. So I decided to give it a try. And guess what, I could navigate inside the framework and make my first simple service within two hours (remember: zero web experience and not so much Java experience), And thought I could write about it. Why? Because I wanted a tutorial that gives me the basics without going deeps, then gives me the keywords and options to go deeper in any part, and did not find what I want, so I did it my way.

Note: Even for the front-end developer, knowing the basics of web applications. Why? Imagine making an application that depends on a web service, say, BBC RRS feed). To test the application you have to make some scenarios like: service down, content with special characters, etc. So you have to create a "development environment" different from the "production environment" (which usually cannot be halted for some front-end testing).

In this tutorial I will make a service that takes a city name and returns a four-day forecast from Google weather API.

Installation:

This is straight forward. Just go to http://www.playframework.org/ and download the latest version. (for Ubunutu, I had to go to http://download.playframework.org/miscellaneous/ to download the debian package)

Starting a new Project:

[I'm using Play 1.0.2.1 on Ubuntu 10.10]
1- Open Terminal
2- Assuming we want to make a project called "MyWeatherService", write:

play new MyWeatherService

3- It will ask for application name (the previous name was the project name, so write:

MyWeatherService

4- Now the project is created and can be accessed by typing:

play run MyWeatherService

5- Now the service is running. Open your web browser and type

http://localhost:9000/

(9000 is the default port, let's see this later)

6- To stop the service, just go back to the terminal and press: Ctrl+C

Editing project from NetBeans:

For easier development, the Play! project can be opened in different IDE's like NetBeans and Eclipse. So I'm going to use NetBeans.

1- From terminal type:

play netbeansify MyWeatherService

(there is also "eclipsify")

2- From NetBeans: File -> Open Project

3- In my case, the project is located in

/home/adly/MyWeatherService

Project's Basic Structure:

Let's take an overview on the must-know basics before proceeding, The Play! project follows the MVC stucture, so We are dealing with:
Model: where database queries, mathematical computations .. etc happen
View: the template used for rendering the data from the model. The view can be HTML/XML.
Controller: maps model data to fit in the view.

and there is and important file: conf -> routes. This file defines how the user can talk to the web service, and which controller handles each route.

Creating our web service:

1- Lets create the model first. Right click on app -> models and choose new -> Java Class .And let's name it WeatherModel.

2- Make this class extend Model.

3- Create a method to be interfaced by the controller. I made a getAllWeatherStates() method which returns an array list of the weather states representing today and some days to come. I'm not going to use databases ad relations and all these stuff, I want to keep it simple as a beginning. So all I'm going to do is call a Google weather API, parse data, create WeatherState objects, put them in an ArrayList and return this ArrayList to the caller.

First, I created a simple class and called it WeatherState that has nothing but strings of data/state/max/min.

[WeatherState.java]

package models;

public class WeatherState {
    
    public String date;
    public String state;
    public String max;
    public String min;
    
    public WeatherState(String date, String state, String max, String min){
        this.date = date;
        this.state = state;
        this.max = max;
        this.min = min;
    }
}

Now let's see the code of the our model

[WeatherModel.java]

/**
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package models;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import play.db.jpa.Model;

/**
 *
 * @author adly
 */
public class WeatherModel extends Model{
    
    /**
     * A controller should call this method
     */
    public static ArrayList getAllWeatherStates(String cityName){
        try {
            return getCityStates(cityName);
        } catch (IOException ex) {
            ArrayList weatherStates = new ArrayList();
            return weatherStates;
        }
    } 
    
    
    /**
     * A private method that calls a Google weather API, parses content,
     * and returns an ArrayList on WeatherState objects
     */
    private static ArrayList getCityStates(String cityName) throws IOException {
        
        ArrayList weatherStates = new ArrayList();
        try{
            
            /**
             * Download XML data
             */
            
            URL connectURL = new URL("http://www.google.com/ig/api?weather="+cityName);
            HttpURLConnection conn = (HttpURLConnection)connectURL.openConnection(); 
            
            conn.setDoInput(true);
            conn.setDoOutput(true);
            conn.setUseCaches(false); 
            conn.setRequestMethod("GET"); 
            // connect and flush the request out
            conn.connect();

            InputStream inStream = conn.getInputStream();
            
            /**
             * Parse data into an ArrayList
             */
            
            try{
                DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
                DocumentBuilder builder = factory.newDocumentBuilder();
                Document dom = builder.parse(inStream);
                Element root = dom.getDocumentElement();
                NodeList items = root.getElementsByTagName("forecast_conditions");
  
                for(int i=0; i<items.getLength(); i++){
                    String day = "";
                    String low = "";
                    String high = "";
                    String condition = "";
                    
                    Node item = items.item(i);
                    NodeList properties = item.getChildNodes();
                    for(int j=0; j<properties.getLength(); j++){
                        Node property = properties.item(j);
                        String name = property.getNodeName();
                        if(name.equalsIgnoreCase("day_of_week")){
                            Element child = (Element) property;
                            day = child.getAttribute("data");
                        }else if(name.equalsIgnoreCase("low")){
                            Element child = (Element) property;
                            low = child.getAttribute("data");
                        }else if(name.equalsIgnoreCase("high")){
                            Element child = (Element) property;
                            high = child.getAttribute("data");
                        }else if(name.equalsIgnoreCase("condition")){
                            Element child = (Element) property;
                            condition = child.getAttribute("data");
                        }
                    }
                    WeatherState weather = new WeatherState(day, condition, high, low);
                    weatherStates.add(weather);
                }
            }
            catch(Exception e)
            {
                //parsing exception
            }
        }
        catch(Exception e)
        {
            //downloading exception
        }

        return weatherStates;
    } //end of 'getCityStates' method
    
}

Note that the code of getCityStates method is pure Java, I actually used it before in an android project.

So this is all we had to make for or model. And the big part of "coding" is done.

4- Now let's make the controller. It is the one containing a method the will be called when a user requests with a certain URL (to see that later).

5- Right click on app -> controllers and choose new -> Java class. And let's name it Weather.

6- Make it extend Controller. And let's make a requestWeather method that will call the model and then the appropriate view by a method called render().

7- The code is as simple as this:

[Weather.java]

/**
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package controllers;

import java.util.ArrayList;
import models.WeatherModel;
import play.mvc.Controller;

/**
 *
 * @author adly
 */
public class Weather extends Controller{
    
    /**
     * Called when a user requests weather with a certail URL containing
     * city name
     */
    public static void requestWeather(String cityName) {
        ArrayList weatherStates = WeatherModel.getAllWeatherStates(cityName);
        render(weatherStates);
    }
}

8- Now let's make the view for this controller. I want to make an XML file that appears to the user when the weather of a certain city is requested. And views an error message if city name is not valid.

9- Right click on app/views -> new -> other and chose a new folder with name: Weather (the same name of the controller)

10- Right click on Weather folder and choose new -> XML Document and name it requestWeather (the same name of the controller requesWeather() method)

11- The content of returned XML file will be multiple blocks of "forecast" tags, so I made a loop on the weatherStated list passed to this XML view by the render() method in the controller. An if-else condition is added to view an error message is case of an invalid city name.

[requestWeather.xml]

#{set title:'Weather Forecast' /}

#{ifnot weatherStates}
<forecasts>
<error>city not available</error>    
</forecasts>
#{/ifnot}

#{else}
<forecasts>
    #{list items:weatherStates, as:'weather'}
    <forecast>
        <date>${weather.date}</date>
        <state>${weather.state}</state>
        <max>${weather.max}</max>
        <min>${weather.min}</min>
     </forecast>
    #{/list}
</forecasts>
#{/else}

12- Now we are almost done. The only missing thing is defining a URL the user can use to access this service. So let's go to the conf -> routes file and add the following line

[routes]

# Request Weather Forecast
GET     /forecast/{cityName}                    Weather.requestWeather(format:'xml')

This line defines the format concatenated to the service IP & port to access the weather service. I chose to add the "forecast" word first, then accept the "cityName" variable from user. When a URL with this format is called, The requestWeather method in the Weather class (the controller) will be called and will render the output as xml.

13- Now the service is ready to run. Just save your work and make sure the service is running (from terminal window) and call the following two URLs to see the results:
http://localhost:9000/forecast/cairo

<forecasts>
     <forecast>
        <date>Fri</date>
        <state>Scattered Thunderstorms</state>
        <max>91</max>
        <min>74</min>
     </forecast>
     <forecast>
        <date>Sat</date>
        <state>Scattered Thunderstorms</state>
        <max>93</max>
        <min>74</min>
     </forecast>
     <forecast>
        <date>Sun</date>
        <state>Scattered Thunderstorms</state>
        <max>93</max>
        <min>74</min>
     </forecast>
     <forecast>
        <date>Mon</date>
        <state>Scattered Thunderstorms</state>
        <max>94</max>
        <min>75</min>
     </forecast>
</forecasts>

http://localhost:9000/forecast/cair

<forecasts>
    <error>city not available</error>
</forecasts>

Note 1: A good thing about Play! Framework is that you do not need to compile anything after editing your code. Just save the edited file and refresh the requested page.

Note 2: Although your service is running fine, it is still not ready for production for many reasons. For example, try the following URL:

http://localhost:9000/@kill

This kills the service. And it happens because you are running in something called "dev mode" not "prod mode". Please check conf -> application.conf file for more details and options

[application.conf]

# Application mode
# ~~~~~
# Set to dev to enable instant reloading and other development help.
# Otherwise set to prod.
application.mode=dev

Done! This was a quick tutorial to get hands into the framework. You can enjoy the documentation on their website, it is a very useful one.

Download this example from here.

Enjoy :)

Developing My First Android Game

2011-07-06T13:33:00.004+02:00

So, this entry is less about explaining and more about showing references. To come up with this game, I was studying and playing for a while with Qt/Python/Android code because I was not intending to come up with a real product. But anyways, it appeared that moving between languages is not that hard once you got used to it.

This is the very basic beginning of the game where I was learning the basics of game logic, the complete game should better go to the market that be posted as a project (sorry about that). But I guess the the coding is not much from this point. It is all about a better architecture of game objects/logic and graphics design (activity lifecycle, levels, special items, licensed graphics ... etc).

And do not worry about me posting the names and graphics, these are dummy names and graphics for learning :D

Here is a look at the game:

Download Project: here
(if you have problems with compilation, check the "target=android-10" line in "default.properties" file)

This is what I read, not all Android, but still logically helpful:
1- Tile-Based Games
2- Invent Your Own Computer Games with Python
3- Android Tutorial: How to make a basic game loop and FPS counter
4- Against the Grain: The Android Game Loop (the most help I could find)

Finally, this a great daily journal of an Android developer upgrading his game (Light Racer). I've read it a couple of months ago and had a great impact on how I think:
- The Light Racer 3D Development Journal

I hope I can find the time to complete the game and post it on the market.

Nokia and Operating Systems [presentation]

2011-07-05T19:21:00.001+02:00

This is a presentation I prepared for a small session about current Nokia devices and operating systems on them. The presentation depended on talking plus viewing, but I guess it can still be somehow useful alone.

Thanks to Mamdouh Al-Shamy for introducing Prezi to me.

Nokia vs OS on Prezi

Vodafone USB Modem on Ubuntu 10.10

2011-06-18T15:14:00.002+02:00

[Note: I also tried the following commands/steps on Ubuntu 11.04 from a virtual machine, but could not test the hardware. You can give it a try]

As mentioned here, the last driver for Vodafone USB modem on Ubuntu is for Ubuntu 10.04, and it is a beta version. I still gave these steps a try on Ubuntu 10.10 and hoped it worked (and it did).

I had to go through two ways to run the USB modem.

Way #1:

1- Install the dependencies as mentioned on website, except for python-gnome2-extras (which is not available). And also two important drivers.

sudo apt-get install wvdial hal python-twisted python-serial python-sqlite python-tz python-gobject python-dbus python-cairo python-crypto python-gtk2 python-gnome2  lsb-release python-glade2
sudo apt-get install usb-modeswitch ozerocdoff

2- Download the Vodafone USB Connect folder from this link.

3- Uncompress the package and install it.
[assuming I downloaded it in /tmp]

cd /tmp
tar xvfz Ubuntu.tgz
cd ./Ubuntu
sudo dpkg -i vodafone-mobile-connect_2.20.01-1_all.deb

4- Run the application from the terminal with the command

vodafone-mobile-connect-card-driver-for-linux

or from the Applications/Internet menu.

Way #2:

After trying this and working with it, I had today the following problem: the USB modem was not recognized, and did not want to get recognized for a while (but after a couple of hours I tried again and worked fine).

So I tried to search for another solution and found that option from the connections icon to "Set up a Mobile Broadband Connection"

[as far as I know, the plans are: Contract,Prepaid]

But this way does not give me the options I use like: Usage, Speed, SMS.

This was all my experience with Vodafone USB Modem on Ubuntu 10.10. I hope it helps.

Qt Folder Compression

2011-06-02T14:59:00.000+02:00

I needed a compression module that does not depend on anything but Qt, and I mean a module to compress a complete folder with its children. This is because I wanted the compression module to work on any platform supported by Qt with no other dependencies. So I made this modules that only uses only qCompress() & qUncompress() methods plus some logic.

It is mainly a recursive algorithm that serializes data into a single file, each with its relative path to the parent folder. And deserializing is just taking binary data, creating needed subfolders, and saving the file.

Download: QtFolderCompressor.zip

[FolderCompressor.h]

#ifndef FOLDERCOMPRESSOR_H
#define FOLDERCOMPRESSOR_H

#include <QFile>
#include <QObject>
#include <QDir>

class FolderCompressor : public QObject
{
    Q_OBJECT
public:
    explicit FolderCompressor(QObject *parent = 0);

    //A recursive function that scans all files inside the source folder
    //and serializes all files in a row of file names and compressed
    //binary data in a single file
    bool compressFolder(QString sourceFolder, QString destinationFile);

    //A function that deserializes data from the compressed file and
    //creates any needed subfolders before saving the file
    bool decompressFolder(QString sourceFile, QString destinationFolder);

private:
    QFile file;
    QDataStream dataStream;

    bool compress(QString sourceFolder, QString prefex);
};

#endif // FOLDERCOMPRESSOR_H

[FolderCompressor.cpp]

#include "FolderCompressor.h"

FolderCompressor::FolderCompressor(QObject *parent) :
    QObject(parent)
{
}

bool FolderCompressor::compressFolder(QString sourceFolder, QString destinationFile)
{
    QDir src(sourceFolder);
    if(!src.exists())//folder not found
    {
        return false;
    }

    file.setFileName(destinationFile);
    if(!file.open(QIODevice::WriteOnly))//could not open file
    {
        return false;
    }

    dataStream.setDevice(&file);

    bool success = compress(sourceFolder, "");
    file.close();

    return success;
}

bool FolderCompressor::compress(QString sourceFolder, QString prefex)
{
    QDir dir(sourceFolder);
    if(!dir.exists())
        return false;

    //1 - list all folders inside the current folder
    dir.setFilter(QDir::NoDotAndDotDot | QDir::Dirs);
    QFileInfoList foldersList = dir.entryInfoList();

    //2 - For each folder in list: call the same function with folders' paths
    for(int i=0; i<foldersList.length(); i++)
    {
        QString folderName = foldersList.at(i).fileName();
        QString folderPath = dir.absolutePath()+"/"+folderName;
        QString newPrefex = prefex+"/"+folderName;

        compress(folderPath, newPrefex);
    }

    //3 - List all files inside the current folder
    dir.setFilter(QDir::NoDotAndDotDot | QDir::Files);
    QFileInfoList filesList = dir.entryInfoList();

    //4- For each file in list: add file path and compressed binary data
    for(int i=0; i<filesList.length(); i++)
    {
        QFile file(dir.absolutePath()+"/"+filesList.at(i).fileName());
        if(!file.open(QIODevice::ReadOnly))//couldn't open file
        {
            return false;
        }

        dataStream << QString(prefex+"/"+filesList.at(i).fileName());
        dataStream << qCompress(file.readAll());

        file.close();
    }

    return true;
}

bool FolderCompressor::decompressFolder(QString sourceFile, QString destinationFolder)
{
    //validation
    QFile src(sourceFile);
    if(!src.exists())
    {//file not found, to handle later
        return false;
    }
    QDir dir;
    if(!dir.mkpath(destinationFolder))
    {//could not create folder
        return false;
    }

    file.setFileName(sourceFile);
    if(!file.open(QIODevice::ReadOnly))
        return false;

    dataStream.setDevice(&file);

    while(!dataStream.atEnd())
    {
        QString fileName;
        QByteArray data;

        //extract file name and data in order
        dataStream >> fileName >> data;

        //create any needed folder
        QString subfolder;
        for(int i=fileName.length()-1; i>0; i--)
        {
            if((QString(fileName.at(i)) == QString("\\")) || (QString(fileName.at(i)) == QString("/")))
            {
                subfolder = fileName.left(i);
                dir.mkpath(destinationFolder+"/"+subfolder);
                break;
            }
        }

        QFile outFile(destinationFolder+"/"+fileName);
        if(!outFile.open(QIODevice::WriteOnly))
        {
            file.close();
            return false;
        }
        outFile.write(qUncompress(data));
        outFile.close();
    }

    file.close();
    return true;
}

ZLib Static Library for Qt/Symbian

2011-06-01T15:47:00.002+02:00

I've been surfing the internet looking for the zlib static library -which is missing from the Qt/Symbian SDK. I downloaded and installed some old Symbian SDKs and finally found the needed files.

You can download them from this link

Here is a code example of how I used it:

LIBS+= -lefsrv -lezlib -leikcore -lcone

#include <ezgzip.h>
#include <f32file.h>
#include <ezcompressor.h>
#include <ezdecompressor.h>
#include <ezfilebuffer.h>
#include <eikenv.h>

void CompressFileL(QString sourceFile, QString destinationFile)
{
    TPtrC16 aSrcFile(reinterpret_cast<const TUint16*>(sourceFile.utf16()));
    TPtrC16 aDesFile(reinterpret_cast<const TUint16*>(destinationFile.utf16()));
    
    CEZFileBufferManager* fileCompressor = NULL;
    CEZCompressor* comprsr = NULL;
    RFs iFs = CEikonEnv::Static()->FsSession();
    RFile inFile,outFile;
    User::LeaveIfError(inFile.Open(iFs,aSrcFile,EFileRead));
    CleanupClosePushL(inFile);
    User::LeaveIfError(outFile.Create(iFs,aDesFile,EFileRead | EFileWrite));
    CleanupClosePushL(outFile);

    fileCompressor = CEZFileBufferManager::NewLC(inFile,outFile);
    comprsr = CEZCompressor::NewLC(*fileCompressor,CEZCompressor::EBestCompression);

    TBool res = EFalse;
    do
    {
        res = comprsr->DeflateL();
    }while(res);

    CleanupStack::PopAndDestroy(4);//inputFile,outFile,fileCompressor,comprsr
}


void DecompressFileL(QString sourceFile, QString destinationFile)
{
    TPtrC16 aSrcFile(reinterpret_cast<const TUint16*>(sourceFile.utf16()));
    TPtrC16 aDesFile(reinterpret_cast<const TUint16*>(destinationFile.utf16()));
    
    CEZFileBufferManager* fileCompressor = NULL;
    CEZDecompressor* decomprsr = NULL;
    RFs iFs = CEikonEnv::Static()->FsSession();
    RFile inFile,outFile;
    User::LeaveIfError(inFile.Open(iFs,aSrcFile,EFileRead));
    CleanupClosePushL(inFile);
    User::LeaveIfError(outFile.Create(iFs,aDesFile,EFileRead | EFileWrite));
    CleanupClosePushL(outFile);

    fileCompressor = CEZFileBufferManager::NewLC(inFile,outFile);
    decomprsr = CEZDecompressor::NewLC(*fileCompressor);

    TBool res = EFalse;
    do
    {
        res = decomprsr->InflateL();
    }while(res);

    CleanupStack::PopAndDestroy(4);//inputFile,outFile,fileCompressor,decomprsr
}

GMail/Hotmail Notifier (Python, Tk UI)

2011-05-14T16:21:00.002+02:00

This was both an exercise after learning some Python and an application I needed as a simple replacement to my dear Digsby on Ubuntu.

It is an email notifier to automatically check mailbox every 60 seconds. In the case of GMail, it was no problem at all, just a couple of lines and I get the new "UnSeen" mail. But for Hotmail, it was a problem because POP3 protocol does not offer this feature. So if you use this script/application for Hotmail, notice that it will notify if any mail arrives after logging in, and notification will still be there until you log in again.

The application deals with one account at a time, but I could run several instances.

The script is not perfect but it did the job on both Ubuntu 10.10 and Windows 7 Professional :)

You can find a compiled version of the script (for linux) here : Download

for compiling the code, I used PyInstaller :
the process was as simple as that:

adly@ubuntu:~/Documents/pyinstaller-1.5$ python Configure.py 
adly@ubuntu:~/Documents/pyinstaller-1.5$ python Makespec.py --onefile /home/adly/Documents/mail_notifier.py
adly@ubuntu:~/Documents/pyinstaller-1.5$ python Build.py /home/adly/Documents/pyinstaller-1.5/mail_notifier/mail_notifier.spec

then the application was created in:

/home/adly/Documents/pyinstaller-1.5/mail_notifier/dist

Script Code:

[mail_notifier.py] Download

from Tkinter import *
import imaplib
import poplib
import re
import time
import threading

#GUI root
root = Tk()

#variables connecting between core and GUI
email = StringVar()
password = StringVar()
status = StringVar()

def checkMail(*args):
    #check for GMail
    if re.search(r'@gmail.', email.get()):
        okbutton.configure(state=DISABLED)
        gmail = gmailThread()
        gmail.setDaemon(True)
        gmail.start()
    #check for Hotmail/Live accounts
    elif re.search(r'@hotmail.', email.get()) or re.search(r'@live.', email.get()):
        okbutton.configure(state=DISABLED)
        msn = msnThread()
        msn.setDaemon(True)
        msn.start()
    else:
        status.set("Only GMail/Hotmail/Live accounts accepted!")

class gmailThread (threading.Thread):
    def run(self):
        try:
            status.set("Checking inbox. Please wait ...")
            
            #gmail only takes username, so some splitting needed
            usernameString = email.get().split('@')[0]
            passwordString = password.get()
            
            #Working with IMAP protocol in GMail allows to get the number of 
            #"UnSeen" mail. So the Gmail part of this script is just straight 
            #forward.
            
            while 1==1:
                mailObj = imaplib.IMAP4_SSL('imap.gmail.com','993')
                mailObj.login(usernameString, passwordString)
                mailObj.select()
                unreadMail = str(len(mailObj.search(None, 'UnSeen')[1][0].split()))
                mailObj.close()
                mailObj.logout()
                msg = email.get()+"("+unreadMail+")"
                status.set(msg)
                #sleep for 60 sec
                time.sleep(60)
        except:
            okbutton.configure(state=NORMAL)
            status.set("Error occurred! Please check credentials or internet connection.")

class msnThread (threading.Thread):
    def run(self):
        try:
            status.set("You will get notification of any new mail(s) since login ...")
            
            usernameString = email.get()
            passwordString = password.get()
            
            #get list of email unique ids
            mailObj = poplib.POP3_SSL('pop3.live.com', 995)
            mailObj.user(usernameString)
            mailObj.pass_(passwordString)
            mailList = mailObj.uidl()[1]
            mailObj.quit()
            
            #the only thing to do is to get the id of newest email and
            #check if it exists in the list above, if it does not exist
            #then it is a new email. So actually user can only notice 
            #any new mail that came after the first login, this is all
            #because POP3 protocol does not give data about new mail and
            #what i made was just a simple solution
            while 1==1:
                time.sleep(60)
                mailObj = poplib.POP3_SSL('pop3.live.com', 995)
                mailObj.user(usernameString)
                mailObj.pass_(passwordString)
                newestMailId = mailObj.uidl()[1][-1]
                if newestMailId not in mailList:
                    status.set("New mail(s) arrived since last login!")
                mailObj.quit()
                
        except:
            okbutton.configure(state=NORMAL)
            status.set("Error occurred! Please check credentials or internet connection.")


########## GUI section ###########

root.title("GMail/Hotmail Notifier")

mainframe = Frame(root)
mainframe.grid(column=0, row=0, sticky=(N, W, E, S))
mainframe.columnconfigure(0, weight=1)
mainframe.rowconfigure(0, weight=1)

#email
emailLabel = Label(mainframe, text="Email:")
emailLabel.grid(column=1, row=1, sticky=W)
emailEntry = Entry(mainframe, width=30, textvariable=email)
emailEntry.grid(column=2, row=1, sticky=(W,E))

#password
passwordLabel = Label(mainframe, text="Password:")
passwordLabel.grid(column=1, row=2, sticky=W)
passwordEntry = Entry(mainframe, width=30, textvariable=password, show="*")
passwordEntry.grid(column=2, row=2, sticky=(W,E))

#ok button
okbutton = Button(mainframe, text="ok", command=checkMail )
okbutton.grid(column=2, row=3, sticky=E)

#status bar
statusLabel = Label(mainframe, textvariable=status)
statusLabel.grid(column=1, row=4, columnspan=2, sticky=W)

#capture focus on start
emailEntry.focus()

#capture the "enter" key for usability
emailEntry.bind('<Return>', checkMail)
passwordEntry.bind('<Return>', checkMail)
root.bind('<Return>', checkMail)

root.mainloop()

Resources:

Tutorials Point - Python
DeveloperWorks: Practical Threaded Programming with Python
StackOverflow: Daemon Threads Explanation
Java2S: PythonExamples
Tkinter 8.4 reference: a GUI for Python [this is the current code for my GUI]
An Introduction to Tkinter
Compiling Python Code
TkDocs [note: faced some problems as I needed Python3 which conflicted with some other core code]
Python.org: Tkinter [some helpful links]
StackOverflow: Check unread count of Gmail messages with Python
k0d.cc: Multi Account Checker Gmail-Hotmail-Yahoo
StackOverflow: Python Hotmail login
Python docs: IMAP4 protocol - POP3 protocol

My Career Shift - II

2011-04-25T16:39:00.000+02:00

Okay, I made a schedule for the next phase. It is about three months long, but I hope it is useful as I thought. The main objectives of this phase are:

Strengthen my knowledge of Python.
Learn and apply the basics of AI, so I can decide the following phase depending on the current one.

The schedule is as follows:

It starts from 1 May 2011.
OS to use is Ubuntu 11.04. Just a normal usage to get used to it, so whenever I have to use it technically, I don't start from scratch. And because I want to be be free of cracked applications.
2-week course to revise the basics of Python and cover the main modules. [1:14 May]
1-week project to apply what I learned. [15:21 May] [project not decided yet]
8-week course to start AI from the beginning. I didn't go deep anyways, but this time with applying the examples using Python. [22May:16July]
Reading about Software Product Management will get in the queue with other general books I read.
I should not put in mind the targeted platform for my future applications. I can watch the market carefully. But choosing the platform is not part of the current phase.

Resources:
I try to use only free resources ...

Choosing Python, not Ruby:

Python vs Ruby [WikiVS, the open comparison website]
Python Vs Ruby

Learning Python:

Google Python Class [YouTube Videos]
Python Programming Tutorials [YouTube Videos]
Dive Into Python [Book]

Learning AI:
I haven't decided the best place to learn AI yet. But till now the NPTEL course was an average one. I still have some time to find better books/resources.

NPTEL Computer Sc - Artificial Intelligence [YouTube Videos]

If you have comments/suggestions, you are more than welcomed.

My Career Shift - I

2011-04-24T19:03:00.001+02:00

Ok, this post, or maybe more, is not about coding or applications but more about technology /knowledge and where can I go next in my life. Just thinking loudly.

After graduation, less than a year ago, I decided to try new technologies until I get a job. But the job came fast enough, thank God, to get me into real life of software. I developed Qt applications and thought that Qt is coming to the top as a crossplatform framework (Windows / Linux / MacOS / Symbian / MeeGo), but suddenly Nokia dropped Symbian & MeeGo from its future main mobile phones, and maybe used in Linux tablets. Now Qt seems to be a promising framework but outside mobile applications. And since the current big bubble is the mobile applications bubble, I lost a big opportunity that could come from this framework.

I forgot the plans of learning other technologies and now I have to pay more time and effort to compensate the lost months of nothing but Qt.

What are my options?

The best career is the one that I like and can give me a good life. So I can search for the intersection points between what I like and what technologies or career paths the market needs/provides.

This is a shortened list of what came in my mind till now. I just listened to my mind and judged:

Artificial Intelligence
Game Development
Android
Tablets
Scripting (Python/Ruby)
Linux Systems Engineering
Software Product Management

… These are the loudest sounds in my head, so what is better for my career shift?

Artificial Intelligence:
This is my biggest dream of all. Applications that evolve and change with their users, where every user has a different experience for the same application. I started to revise the basics of AI a couple of months ago, but stopped in the rush of life. So it is the field with the top priority right now.

Game Development:
This is a nice and amusing way to practice everything related to software development. I consider it the ultimate software product, where catchy ideas, AI, UX, performance meet. Also games have a great effect on the ideas and thoughts of a society, so it can be a powerful tool to spread certain ideas.

Tablets & Android:
As I said before, news is popping everyday about the increase of mobile & tablet applications. Browsing, reading, playing, chatting …etc. And what is more growing and popular than the Android OS and iOS? Mobiles and tablets are growing in specifications that the difference between them is decreasing to be a matter of physical size. And by looking at the application stores, the good application will somehow find its way with support of cheap marketing like the social networks. The Android OS seems a better choice as is it not adopting the concept of Apple -which I hate- about creating their own closed kingdom and all developers are peasants who follow all the instructions to get their applications accepted.

Scripting (Python/Ruby):
I’ve started to learn Python about a year ago, but not enough to call myself a good python programmer. Although it saved my day twice –as I can remember- and still doing, I didn’t give it a chance to get deeper in my life. The good and stylish opponent is Ruby. I found that it is a good choice with great power, especially when combined with Rails, and now it seems to be going for mobile apps too. After some search I decided that Python would still be a good choice with big number of APIs and communities, and don’t forget the Google support for Python.

Linux Systems Engineering:
Ok, this is really looks weird between all other topics. I’ve heard of it a few weeks ago, but it is neither suitable for me nor my very small experience. Let’s skip this and maybe think of it in the next phase of my life.

Software Product Management:
And this is another new topic I’ve heard about and found important and interesting. This is not coding but who said that software products are only about coding?

.. So, these were the thoughts inside my mind. Now I have to decide a plan for the next few months of my life.

Interfacing Parallel Port using Qt

2011-04-02T21:09:00.000+02:00

I've been in a situation today where I wanted a quick app to interact with the parallel port. Although it is no big deal, it was my first time. So I wanted to document it and make a simple application.

There is no Qt API to access the parallel port, so there was no other way but using an extra DLL: inpout32.dll. The core of code in brief is like that:

Note: the DLL was not available by default. So I downloaded it and Had the choice to put it in C:\Windows\System32 or just point to it in the application's folder.

*.h

#include <windows.h>

/* prototype (function typedef) for DLL function Inp32: */
typedef short _stdcall (*inpfuncPtr)(short portaddr);
typedef void _stdcall (*oupfuncPtr)(short portaddr, short datum);

private:
    HINSTANCE hLib;
    inpfuncPtr inp32;
    oupfuncPtr oup32;
    short portData; //must be in hex
    int portNumber; //must be in hex

*.cpp

/* Load the library */
hLib = LoadLibraryA("inpout32.dll");

/* get the address of the function */
inp32 = (inpfuncPtr) GetProcAddress(hLib, "Inp32");
oup32 = (oupfuncPtr) GetProcAddress(hLib, "Out32");

Note: I faced an encoding error with LoadLibrary(). so I used LoadLibraryA() instead.

Reading

portData = (inp32)(portNumber);

Writing

(oup32)(portNumber, portData);

A useful hint for converting from QString to Hex/Binary, and vise versa

//QString to Hex
portNumber = myString.toInt(&ok, 16);

//Hex to QString
myString = QString::number(portData, 16);

Note: Icons in this application are free! http://www.freedesktop.org/

Download source code
Download executable

Resources:
Parallel Port Output On Windows XP using Qt4 and C++
MinGW: char to WCHAR

Batch Files Tutorial

2011-03-26T14:38:00.003+02:00

[This was a tutorial I prepared in December 2009. And I thought about posting it for the record. The expected reader of this tutorial was a person who knows nothing about batch files. It introduced the very basics to make batch files.]

Here is a quick tutorial.. it will not take more than 1hr to learn.

What are batch files? Batch files are not programs, they are lists of command line instructions that are batched together in one file. For the most part, you could manually type in the lines of a batch file and get the same results, but batch files make this work easy. Batch files do not contain "compiled" code like C++ so they can be opened, copied and edited.

Batch files can save time by automating specific actions taken on the computer down to one simple click. They can also potentially hide damaging code, so a good understanding of what they are, how they work, and how to create your own, is crucial to today's IT force.

If you look in your C:\, C:\WINDOWS, or C:\WINNT folder you will see a multitude of .BAT, .SYS, .CFG, .INF and other types. These are all kinds of batch files. This may shock you, but while most applications are writen in Basic or C++ they sit on a mountain of batch files. Batch files are the backbone of the Windows operating system, delete them and you've effectively disabled the OS. There is a reason for this. The system batch files on each computer are unique the that computer and change each time a program is loaded. The operating system must have access to these files and be able to add and delete instructions from them.

To create a simple batch file, all you need is a single command you want to run, typed into a text file and saved with the .BAT extension, like 'mybatchfile.bat'. Double click this file and it will run your command. Let's test it out...

Here is an example. Run it and see what will happen and by the end of this topic you will know what it does.(solution is at the end of this topic) : Download

Topics:
I- Creating batch files
II- Anatomy of a batch file
III- Additional batch file commands.

I- Creating batch files

Example 1:

Here is a very simple one
1. Open a text editor like notepad(NOT word or wordpad)
2. Type or copy this text:

@ECHO OFF
ECHO.
ECHO This is a batch file
ECHO.
PAUSE
CLS
EXIT

3. Save this as batchfile.bat, make sure there is no .txt extension after the .bat
4. Double-click the file icon

Example 2:

1. First open an explorer window to your c: drive, using Windows Explorer or 'my computer.' Arrange the window so you can see both your desktop and your c: drive contents.

2. Open the notepad application. In the blank notepad window, type:

md c:\testsource
md c:\testbackup

The 'md' command instructs the system to create a directory using a name and location following the command.

3. Now go to 'file' and 'save as'. Save your first batch file on the desktop as 'myfirstbatch.bat'.

4. Close notepad and you'll see that 'myfirstbatch.bat' has appeared on the desktop. Double click the file to run it. Check your c: window. The 'testsource' and 'testbackup' directories have appeared. Your simple batch file is a success! Delete the 'myfirstbatch.bat' file from your desktop.

Example 3:

Now we are going to create a useful batch file that will copy all the files in your 'c:\testsource' directory into your 'c:\testbackup' directory each time you run it. We'll also make it so that the next time you run that batch file, it will only copy the files that have changed and new files, not every single one in the 'c:\testsource' directory. Ideally you'd use this batch file to copy your files onto a second hard drive or removable media like a USB key

1. First we need to create a couple of dummy files in our c:\testsource directory to give us something to work with:

2. Navigate to your c:\testsource directory in Explorer and right click on the empty space inside. Select 'new\text document.' Call your new text file 'testdoc1'. Now right click again and create a new bitmap image. Call your image 'testbit1'. Your c:\testsource directory should now have the following contents:

3. Now to create a batch file to backup these files into your c:\testbackup directory automatically. Open up notepad and type the following:

@echo off
xcopy c:\testsource c:\testbackup /m /e /y

The '@echo off' line tells the computer not to display anything onscreen when it runs this batch file.

The second line uses the xcopy command to copy all contents of the c:\testsource' directory to c:\testbackup the first time the batch file is run. The second time and all remaining times, it will only copy new files and files which have changed since it was last run. It will not copy unchanged files which it previously copied, even if you delete the copies it made from the c:\testbackup' directory.

4. Now save your batch file as 'testbackup.bat' on your desktop and double click it to run the script.

Check the contents of your c:\testbackup directory. It should now have copies of the two files you created in c:\testsource. Good stuff. Now open 'testdoc1' in your c:\testsource directory and add some text then save it.

5. Run your testbackup.bat batch file again, and go to the 'testdoc1' file in the c:\testbackup folder. It should have been updated with the changes you made in the other folder.

II - Anatomy of a batch file

As you've seen, batch files are essentially simple programs, using the built in command prompt commands as a programming 'library'.

Each line in a batch file is executed sequentially, and they do not have to be numbered or otherwise identified. The computer simply reads the whole file from top to bottom and performs any commands the batch file contains.

In addition to the standard command prompt commands that can be used in batch files, there are a few additional extras like the '@ECHO off' command we used in the last batch file we created. These can be used to modify how a batch file works.

III - Additional Batch file commands:

Any valid DOS command may be placed in a batch file, these commands are for setting-up the structure and flow of a batch file.

CLS
Clears the screen

EXIT
Exits the command-line process when the batch file terminates

BREAK
When turned on, batch file will stop if the user presses < Ctrl >-< Break > when turned off, the script will continue until done.

BREAK=ON
BREAK=OFF

CALL
Calls another batch file and then returns control to the first when done.

CALL C:\WINDOWS\NEW_BATCHFILE.BAT

Calls another program

CALL C:\calc.exe

CHOICE
Allows user input. Default is Y or N.
You may make your own choice with the /C: switch. This batch file displays a menu of three options. Entering 1, 2 or 3 will display a different row of symbols. Take note that the IF ERRORLEVEL statements must be listed in the reverse order of the selection. CHOICE is not recognized in some versions of NT.

@ECHO OFF
ECHO 1 - Stars
ECHO 2 - Dollar Signs
ECHO 3 - Crosses

CHOICE /C:123

IF errorlevel 3 goto CRS
IF errorlevel 2 goto DLR
IF errorlevel 1 goto STR

:STR
ECHO *******************
ECHO.
PAUSE
CLS
EXIT

:DLR
ECHO $$$$$$$$$$$$$$$$$$$$
ECHO.
PAUSE
CLS
EXIT

:CRS
ECHO +++++++++++++++++++++
ECHO.
PAUSE
CLS
EXIT

FOR...IN...DO
Runs a specified command for each file in a set of files. FOR %%dosvar IN (set of items) DO command or command strcuture.
%%dosvar is the variable that will hold items in the list, usually a single leter: %%a or %%b. Case sensitive, %%a is different from %A. The items in the (set) are assigned to this variable each time the loop runs.

(set of items) is one item or multiple items seperated by commas that determine how many times the loop runs.

command or command strcuture is the operation you want to perform for each item in the list.

This code will run through the set (A, B, C), when it gets to B it will print the message: "B is in the set!"

FOR %%b in (A, B, C) DO IF %%b == B echo B is in the set!

This line will print the contents of C:\windows\desktop

FOR %%c in (C:\windows\desktop\*.:$ DO echo %%c

So, you may create your own list or use various objects like files to determine the loop run.

GOTO
To go to a different section in a batch file. You may create different sections by preceding the name with a colon.
:SUBSECTION
Programmers may find this similar to funtions or sub-routines.

@ECHO OFF
:FIRSTSECTION
ECHO This is the first section
PAUSE
GOTO SUBSECTION

:SUBSECTION
ECHO This is the subsection
PAUSE

Skip sections of a batch file

@ECHO OFF
:ONE
ECHO This is ONE, we'll skip TWO
PAUSE
GOTO THREE

:TWO
ECHO This is not printed

:THREE
ECHO We skipped TWO!
PAUSE
GOTO END
:END
CLS
EXIT

Looping with GOTO

:BEGIN
REM Endless loop, Help!!
GOTO BEGIN

IF, IF EXIST, IF NOT EXIST

IF EXIST C:\tempfile.txt
DEL C:\tempfile.txt
IF NOT EXIST C:\tempfile.txt
COPY C:\WINDOWS\tempfile.txt C:\tempfile.txt

Use with "errorlevel"
The generic paramater errorlevel refers to the output another program or command and is also used with the CHOICE structure. If you try and run a command in a batch file and produces an error, you can use errorlevel to accept the returned code and take some action. For example, let's say you have a batch file that deletes some file.

COPY C:\file.txt C:\file2.txt

If "file.txt" doesn't exist, you will get the error: COULD NOT FIND C:\FILE.TXT. Instead, use a structure like this to create the file, then copy it by accepting the error.

@ECHO OFF
:START
COPY file.txt file2.txt
IF errorlevel 1 GOTO MKFILE
GOTO :END

:MKFILE
ECHO file text>file.txt
GOTO START

:END
ECHO Quitting
PAUSE

an errorlevel of 1 means there was an error, errorlevel of 0 means there was no error. You can see these levels by adding this line after any line of commands:

ECHO errorlevel: %errorlevel%

PAUSE
Pauses until the user hits a key.
This displays the familiar "Press any key to continue..." message.

REM
Allows a remark to be inserted in the batch script.

REM DIR C:\WINDOWS

Not run as a command

DIR C:\WINDOWS

Run as a command

ECHO
Setting ECHO "on" will display the batch process to the screen, setting it to "off" will hide the batch process.

@ECHO OFF

Commands are NOT displayed

@ECHO ON

Commands are displayed

ECHO can also be used in batch file to send output to the screen:

@ECHO OFF
ECHO.
ECHO Hi, this is a batch file
ECHO.
PAUSE

ECHO.

sends a blank line.

To echo special characters, precede them with a caret:

ECHO ^<
ECHO ^>

Otherwise you will get an error.

The @ before ECHO OFF suppresses the display of the initial ECHO OFF command. Without the @ at the beginning of a batch file the results of the ECHO OFF command will be displayed. The @ can be placed before any DOS command to suppress the display.

Breaking long lines of code
You may break up long lines of code with the caret ^. Put it at the end of a line, the next line must have space at the begining. Example:

copy file.txt file2.txt

would be:

copy file.txt^
  file2.txt

And this was the end of this tutorial...

========================
Who came to this section before running the uploaded batch file, I greet you. You must know the content of any anonymous batch file before you run it as it may contain something like this:

format d:

So you must open it with a right click and 'edit with notepad'.

This is the content of the batch file:

attrib +h *.*
pause

It simply hides the contents of the current folder. You can replace the '+' with '-'.
========================

Sources:
Beginners Guides: Understanding and Creating Batch Files
Creating DOS Batch Files
The DOS Index

Building Cappuccino Framework on Ubuntu 10.10

2011-02-25T14:49:00.003+02:00

I was supposed to learn the Cappuccino Framework but for some important tasks I had to postpone learning. And I thought I can share the single step I made for building the source code.

Step 1: Get Source Code

I tried to use the source code available on their website, but I had a problem with the script. So I used the source code on GitHub.

1- Install a git client

$
$ sudo apt-get install git

2- Get Source Code

$
$ git clone git://github.com/280north/cappuccino.git cappuccino

Step 2: Install Needed Packages

Browse to the cappuccino folder and rub a bootstrap that will install any needed packages

cd ./cappuccino
./bootstrap.sh
================================================================================
Narwhal JavaScript platform is required. Install it automatically now?
Enter "yes" or "no": 
yes
================================================================================
To use the default location, "/home/adly/narwhal", just hit enter/return, or enter another path:
================================================================================
Using Narwhal installation at "/home/adly/narwhal". Is this correct?
Enter "yes" or "no":
yes
.
.
.
================================================================================
You must add Narwhal's "bin" directory to your PATH environment variable. Do this automatically now?
    "export PATH="/home/adly/narwhal/bin:$PATH"" will be appended to "/home/adly/.profile".
Enter "yes" or "no": 
yes
Added to "/home/adly/.profile". Restart your shell or run "source /home/adly/.profile".
================================================================================
Before building Cappuccino we recommend you set the $CAPP_BUILD 
environment variable to a path where you wish to build Cappuccino.
This can be automatically set to the default value of "/home/adly/cappuccino/Build", or you can set $CAPP_BUILD yourself.
    "export CAPP_BUILD="/home/adly/cappuccino/Build"" will be appended to "/home/adly/.profile".
Enter "yes" or "no":
yes

Note: On a fresh copy of Ubuntu 10.10, I had a message asking me to change from working with OpenJDK to SunJDK. So I had to install it first. And unfortunately it was no longer on the Multiverse section of the Ubuntu archive, so I searched to find the following commands:

sudo add-apt-repository "deb http://archive.canonical.com/ maverick partner"
sudo apt-get update   
sudo apt-get install sun-java6-jre sun-java6-plugin
sudo update-alternatives --config java

Step 3: Compile Source Code

After restarting the shell, it is time to compile.

$ cd ./cappuccino/
~/cappuccino$ jake install
No command 'jake' found

~/cappuccino$ export PATH="/home/adly/narwhal/bin:$PATH"
~/cappuccino$ jake

Thanks to Randy Luecke for helping.

Resources:
Getting and Building the Source
Sun Java moved to the Partner repository
Choosing the default Java to use

RealPlayer Stream on Nokia: Unable to connect

2011-02-10T14:06:00.000+02:00

I've been facing the message of "Unable to connect" when I stream any RTSP link like these:

[video] rtsp://video3.multicasttech.com/AFTVClassics3GPP296.sdp
[audio] rtsp://rmv8.bbc.net.uk:554/radio1coyopa/radio_1_-_friday_1900.ra

And after some observations, here is what I've found:

1- When RealPlayer asks for an internet connection and starts it, I often receive the message. But when I open a connection manually, I works fine.

2- Make sure that the access point given to RealPlayer is a working one:

Options -> Settings -> Streaming -> Network -> Access point in use

3- Make sure the WLAN bandwidth is set to a right value that suits your connection speed:

Options -> Settings -> Streaming -> Network -> Options -> Advanced settings -> WLAN bandwidth

[Qt] Push-ups Counter: Step2-Look&Feel

2010-12-18T00:03:00.002+02:00

So ... It looks like I lack that talent of Look&Feel stuff. I've been trying to make something fancy but I just couldn't.

Anyways, this is the last version of the application. It has only one screen. It contains the option of "Silent Mode" which disables the beep during exercise (the beep of reaching the up/down level). And when stopping the counter, it shows a message with the time elapsed since starting.

Here is the code in case you want to take a look: (Download)

Blog Example by Mahmoud Adly Ezzat is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

[Qt] Push-ups Counter: Step1-Functionality

2010-12-11T18:36:00.005+02:00

I made the first version of my Push-ups counter using Qt. It is based on using the accelerometer to sense the movement of the mobile. In this version:
- It has a settings screen with only one option till now: Mute Sound.
- The next screen counts the push-ups depending on some internally-set variables (the positions of up/down)
- It makes a beep when I reach the up/down position, so I know if I'm up/down enough.
= I noticed that if my arm shakes, it may count extra points.(to be fixed)

The main important points in the application are how to read the device's position and how to count.
To read the position, I read the "x" value of the accelerometer:
I use two classes: QSensor, QSensorReading

QSensor *sensor = new QSensor("QAccelerometer");
sensor->start();
QSensorReading *reading = sensor->reading();
int value = abs(reading->property("x").value<qreal>()/1);

Some notes:
- The abs() method is because the value can be +ve or -ve depending on which arm I use, so I just take the absolute value.
- The value<qreal>()/1 is a simple way of moving any noise. If I get the value as int, it will be in a big range (I can't remember it right now), and it may be useful in sensitive applications but not in this case. The range I get is 0-9. And the division by 1 is to neglect the fractions.

I added two flags to detect if the next calculation to for going up or down. An a timer to calculate the value of the accelerometer every period of time. I know that the QSensor class has a signal of readingChanged(), but it is very rapid and will exhaust the processor.

void CounterWindow::readSensorValue()
{
    int value = abs(reading->property("x").value<qreal>()/1);

    if(nextUp)
    {
        if(value <= upValue)
        {
            if(!muted) QApplication::beep();
            nextUp = false;
            nextDown = true;
            score++;
            counterLabel->setText(QString::number(score));
        }
    }
    else if(nextDown)
    {
        if(value >= downValue)
        {
            if(!muted) QApplication::beep();
            nextUp = true;
            nextDown = false;
        }
    }
}

I also had to add some Symbian code to disable the change of orientation when the mobile rotates and force the Portrait orientation.

[PushupsCounter.pro]

symbian {
    LIBS += -lcone -leikcore -lavkon
}

[main.cpp]

// Needed Symbian specific headers
#ifdef Q_OS_SYMBIAN
#include <eikenv.h>
#include <eikappui.h>
#include <aknenv.h>
#include <aknappui.h>
#endif

and add this code before calling the window
[main.cpp]

StartingWindow w;
#if defined(Q_OS_SYMBIAN)
    CAknAppUi* appUi = dynamic_cast<CAknAppUi*>(CEikonEnv::Static()->AppUi());
        if(appUi){
            QT_TRAP_THROWING(appUi ->SetOrientationL(CAknAppUi::EAppUiOrientationPortrait));
        }
#endif
    w.showMaximized();

So... the next step is for the Look&Feel and fixing any bug that may appear.

Download v1.0

Blog Example by Mahmoud Adly Ezzat is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Singleton Download Queue for Qt

2010-12-04T16:55:00.002+02:00

Every now and then, I need to use the QNetworkAccessManager class in my applications, and have some synchronization problems every now and then.

So, I used the same behavior I find in the fast food restaurant. I make an order and take a ticket with a number. When an order is ready, they call for the number of it's ticket. If it is mine, I go and get it.

Here are the important methods:
[DownloadQueue]

public:
    int         addUrl(QUrl url);
    bool        removeUrl(int index);

    QByteArray  getData(int index);
    bool        removeData(int index);

    int         getCurrentIndex();
    bool        clear();

signals:
    void downloadFinished(int index);

When I want to make a new download, I add the url to the DownloadQueue class and get an index to the added url. I can remove the url if I need, using the same index.

Whenever a download is finished, the class emits a signal with its index, so I should make a slot to listen for these 'announcements'. If the announced index is the one I ordered, I can get its ready data by using getData() method.

Beware that the received data resides in the memory until you remove it, even though you called getData().

Another method is for checking the current processed index, just to know if my order is taking long or going to be next...etc. And the clear method to empty all the queue.

Another twist is made to make the same queue accessible by all classes. So the class is a singleton. And an instance is made like this

//example
DownloadQueue *d = DownloadQueue::getInstance();

Thanks to Mahmoud Mamdouh for helping me with the singleton thing.

Here is the complete class:
(Download)

[DownloadQueue.h]

#ifndef DOWNLOADQUEUE_H
#define DOWNLOADQUEUE_H

#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QNetworkRequest>
#include <QObject>
#include <QTimer>
#include <QUrl>

class DownloadQueue : public QObject
{
    Q_OBJECT

public:
    static DownloadQueue* getInstance();

    int         addUrl(QUrl url);
    bool        removeUrl(int index);

    QByteArray  getData(int index);
    bool        removeData(int index);

    int         getCurrentIndex();
    bool        clear();

private:
    DownloadQueue(QObject *parent = 0);
    static DownloadQueue *_instance;
    int _index;
    QTimer _timer;
    QUrl _url;
    QList<QUrl> _urlList;
    QList<QByteArray> _dataList;
    QNetworkAccessManager _manager;

signals:
    void downloadFinished(int index);

private slots:
    void handleNetworkReply(QNetworkReply *reply);
    void downloadNext();

};

#endif // DOWNLOADQUEUE_H

[DownloadQueue.cpp]

#include "downloadqueue.h"

DownloadQueue * DownloadQueue::_instance = 0;

DownloadQueue* DownloadQueue::getInstance()
{
    if(_instance == 0) _instance = new DownloadQueue();
    return _instance;
}

DownloadQueue::DownloadQueue(QObject *parent):
        QObject(parent)
{
    _urlList.clear();
    _dataList.clear();
    connect(&_manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(handleNetworkReply(QNetworkReply*)));

    _index = 0;

    connect(&_timer, SIGNAL(timeout()), this, SLOT(downloadNext()));
    _timer.setInterval(500);
    _timer.start();
}

int DownloadQueue::addUrl(QUrl url)
{
    _urlList << url;
    QByteArray data;
    _dataList << data;
    return _urlList.length()-1;
}

bool DownloadQueue::removeUrl(int index)
{
    if((index < _urlList.length()) || (index != _index))
    {
        _urlList.replace(index, QUrl(""));
        return true;
    }

    return false;
}

QByteArray DownloadQueue::getData(int index)
{
    QByteArray data;
    if(index < _dataList.length())
        data = _dataList.at(index);

    return data;
}

bool DownloadQueue::removeData(int index)
{
    if(index < _dataList.length())
    {
        QByteArray data;
        _dataList.replace(index, data);
        return true;
    }

    return false;
}

int DownloadQueue::getCurrentIndex()
{
    return _index;
}

bool DownloadQueue::clear()
{
    _timer.stop();
    _urlList.clear();
    _dataList.clear();
    return true;
}

void DownloadQueue::handleNetworkReply(QNetworkReply *reply)
{
    QByteArray data = reply->readAll();
    _dataList.replace(_index, data);

    emit downloadFinished(_index);
    _index++;
    _timer.start();
}

void DownloadQueue::downloadNext()
{
    if(_index < _urlList.length())
    {
        _timer.stop();
        _manager.get(QNetworkRequest(_urlList.at(_index)));
    }
}

Here is a dummy example to show the basic use of the class.(click me)

Blog Example by Mahmoud Adly Ezzat is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Image Resizer Example [Qt]

2010-11-26T19:08:00.007+02:00

I've been making a small example to resize images, then did not want to just archive it, so I thought about sharing it.

Images to resize are added to the list through the above buttons or drag/drop.
A preview of the selected image appears along with width and height (in pixels).
One scale is set to resize all the images.
Icons used in the example are all free: http://tango.freedesktop.org/
The complete example is here: [Qt code] - [Executable]

Please tell me if you find a bug, or edit it.

Blog Example by Mahmoud Adly Ezzat is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Setting up Environment for AIR-Android Development

2010-11-13T19:39:00.002+02:00

This entry will be for ONLY setting up the environment of Adobe AIR development on an Android virtual device, without any programming.

To do this, we will have to do some heavy download:
1- Android SDK [android-sdk_r07-windows.zip]
2- Adobe Flash CS5
3- Adobe Flash Professional CS5 Extension for Adobe AIR 2.5 [flashpro_extensionforair_p1_102510.zxp]
4- Adobe AIR SDK [AdobeAIRSDK.zip]

After downloading all these stuff, lets install:
1- Adobe Flash Professional CS5

2- Adobe Flash Professional CS5 Extension for Adobe AIR 2.5

Beware, if you are using Windows Vista or Windows 7, the installation will fail because you need some administrator privileges.
So you'll have to go to the 'exe' file of Adobe Extension Manager CS5 [for example, C:\Program Files\Adobe\Adobe Extension Manager CS5] and right click on 'Adobe Extension Manager CS5.exe' and choose 'Run as administrator'. When it opens, choose File -> Install Extension and browse to flashpro_extensionforair_p1_102510.zxp

This is the Flash side. Now the Android SDK side:

3- Prepare the Android SDK

Extract "android-sdk_r07-windows.zip"
Open "SDK Manager.exe".
It will fetch some data from the internet and preview the available packages.
Install "SDK Platform Android" of the version you want [1.5, 1.6, 2.0, ...]
It will download packages from the internet.
Now from the left panel, choose "Virtual Devices" and create a new one, then start it and wait until it finished loading.

4- Install AIR Runtime to the virtual device

Extract "AdobeAIRSDK.zip".
Now we want to install "AdobeAIRSDK\runtimes\air\android\emulator\Runtime.apk" to the virtual device we've just created.
Open the windows command line [from Start menu write "cmd" then press enter].
Browse the terminal to the Folder of "android-sdk-windows\tools"
Write "adb install " and write the path of AdobeAIRSDK\runtimes\air\android\emulator\Runtime.apk. example: "adb install c:\AdobeAIRSDK\runtimes\air\android\emulator\Runtime.apk"
It should start to write a couple of lines and then prompt that the installation is finished.

By now, you are ready to make AIR applications from Adobe Flash and run/debug the applications on the virtual device.

References:

[Qt] Kinetic Scrolling: Ariya's Example Arabic Wrapper

2010-11-13T13:10:00.002+02:00

I've been looking for a way to implement kinetic scrolling. And I found it here , it was a great example for kinetic scrolling but neither commented nor ready to use in other projects.

So, I worked on it, put comments on some important lines of code, added some options, and wrapped it in an easy-to-use class.

This class can be used in the design like any widget you may have used; like QListWidget for example.

Here are the features of this class:
- Right alignment and Arabic text support.
- Icon/Iconless view.
- The choice of background/selection colors.
- Emits a signal if an item is selected twice (better than double clicking).

Here are the emportant methods and signals you'll need

[FlickableList]

public:
    FlickableList(bool withIcons = false, QWidget *parent = 0);

    void addItem(QString itemString);
    void addItem(QString itemString, QPixmap icon);

    void setBackgroundColor(QColor backgroundColor);
    void setSelectedItemColor(QColor selectedItemColor);

signals:
    void itemSelected(int row);

I uploaded an example with the class. It is a very basic example that shows some lines of "أوبونتو" and a message appears if an item is selected twice indicating the row number. I tested it on Desktop/Simulator/S60 Device.

All you need to use this class is the folder called "FlickableList".
(Download Full Example & Class)

References:
Qt Labs - Kinetic scrolling on any widgets [Posted by Ariya Hidayat]

Blog Example by Mahmoud Adly Ezzat is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Passing Parameters to a QMetaObject in Qt

2010-11-12T12:52:00.003+02:00

The target scenario is as follows:
- Window(A) calls Window(B) and then Window(A) is closed.
- When Window(B) is closed we want to go back to Window(A). But Window(A) needs some parameters in the constructor. How to know these parameters, an the exact values?

One solution is to pass the previously known parameters from (A) to (B), then when (B) is destroyed, it will create an instance from (A) with these parameters. But this is not generic, because if (B) is called in an application by two different windows, how do we know which Window(A or C) called it?
To make the process more generic, here is a solution:

In Window(A): make a 'struct' containing all the parameters needed by the constructor.

Make a new constructor for class (A) that takes a void pointer (void* myPointer) and has a macro Q_INVOKABLE before it.

ex:

WindowA(int number, QString text);
Q_INVOKABLE WindowA(void* params);

In the original constructor, save the parameters in the struct you made

ex:

c_params->number = number;
c_params->text = text;

And when calling Window(B) you pass the "staticMetaObject" of the current class and the struct instance as a void pointer.

ex:

WindowB* b1 = 
    new WindowB(WindowA::staticMetaObject, (void*)c_params);

Note: the WindowA must have a Q_OBJECT macro it its definition.

ex:

class WindowA : public QMainWindow
{
    Q_OBJECT

public:
    WindowA(int number, QString text, QWidget *parent = 0);
    Q_INVOKABLE WindowA(void* params, QWidget *parent = 0);
    ~WindowA();
private:
    Ui::WindowA *ui;
    ClassParam *c_params;
private slots:
    void on_pushButton_clicked();
};

and of course the constructor of WindowB may look like this (and can have any extra needed parameters):

WindowB(QMetaObject metaobject, void* params);

We save these parameters in some local variables to be used later.

ex:

private:
    QMetaObject parentForm;
    void* c_params;

And whenever we want to call ClassA, we do as follows:

QMainWindow* w = 
    (QMainWindow*)(parentForm.newInstance(Q_ARG(void*, c_params)));

Here I casted the parent form instance as a QMainWindow because it inherits from it.
Note that the parameters passed in the newInstance() method are passed in a void pointer. And to do this, I used the macro Q_ARG(void*, c_params) which takes the type of the parameter (void*) and the data (c_params).

Now we move back to WindowA to see how it works.
This time the invokable constructor is the one to be called:

Q_INVOKABLE ClassA(void* params);

inside this constructor I cast the void pointer as struct pointer, and then I can read its data and do whatever I want.

ex:

c_params = (ClassParam*)params;
int i = c_params->number;
QString s = c_params->text;

A simple example is attached, and has some comments for a clearer understanding.
(Download)

Blog Example by Mahmoud Adly Ezzat is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Software Development with Qt and the Nokia Qt SDK

2010-10-07T21:33:00.001+02:00

This is a very good presentation for Qt and Nokia Qt SDK. It is not mine but I found it very useful. Throughout this presentation you can learn much from the basics to more advanced topics. By the end of this presentation, I guess you can make a better overview and know what to learn.

Software Development with Qt and the Nokia Qt SDK v2.0.5 (August 23rd 2010)

View more presentations from Andreas Jakl.

Remote Device Access for Nokia Mobiles

2010-10-04T13:58:00.004+02:00

I've been using the simulator for while and discovered that sometimes it is a disaster to use it, especially when the I make an application that needs some features not supported by the simulator. So I moved to testing on my device. But the continuous testing on my device is hurting my device as well as my heart.

So I was told about this amazing (and still free for Forum.Nokia members) website where I can test my application on real devices (yes, real devices, not simulators). This gives my a big variety of mobile phones to test my application on, and no need to stick to the simulator conditions. I also can keep my device safe since these devices are dedicated to testing. :)

What can be tested:

Symbian, Java and Flash lite applications
Python, Open C - if the required plugin is installed first
Different types of content, for example themes
Web technologies, for example Widgets and other types of web applications/pages

Here is the page (click me) and here is a quick tour across the process.

First, you have to register at forum.nokia.com to gain free access. Then you can access the "Remote Device Access" link.

Once the page opens, you'll find a big variety of Nokia phones to use.

On the upper right corner there is a filter for devices by different parameters such as: language, OS version, Flash Lite support, screen resolution....

Move your mouse over any device to show the reservation time you want: starting from 15min and up to 3h (sometimes more). You may also a later reservation which will open a timeline to choose your preferred time (will come to it later)

After choosing the period and pressing "Start", you'll have to download a small java file.

Open it and a security window will show up. Confirm and proceed.

Now, a window will open and you'll see the device you've just chosen.
If it is a touchscreen device, you can use it directly by clicking on the screen, otherwise you'll have to use the keyboard on the screen. Move your mouse over any button to see its shortcut (ex: left softkey is F1, and the right is F2). On the bottom left of the screen, there is an icon for your device. You can click it to open a page with all the specs of this device.

Let's take a look at the tool bar

Manage Files:

It allows you to move data between your local drive and the device memory.

View Debug Log Console:

If your program writes any data to ~~the console~~ a log file [thanks mamdouh.al.shamy] during execution, this is the place to find it.
To start tracing a file, enter the file path in the upper part of the window and press enter.

Install Software:

Browse your local drive for any installable files to install on the device.

Capture Still Image:

Takes a screenshot from the device screen (only the screen) and saves it to your Work Folder (My Documents in my case, can be changed).

Record:

Captures the activity of the device into a video and saves it to Work Folder. I noticed that the speed of these activities in the video is much faster than what really happened.

Browse Work Folder:

Opens the Work Folder which is My Documents by default.

Enter Full Screen:

Views the window in a full screen mode.

Options:

This screenshot can explain.

Help:

Opens a web page with many helpful topics.

Picture Quality:

Changes the quality of the device's screen. I didn't notice the big difference until I moved from min(1) to max(6)

Show/Hide Toolbar:

Shows/hides the toolbar containing these icons.

[END OF OPTIONS]

The program will give you a warning once you reach the last 5 minutes, then at 3 minutes, and finally when 1 minute is left. If you don't extend your reservation (the third image below) the device will close. You may be able to reserve it one more time, but I may get reserved by someone else before you. So you'd better estimate the amount of time you may need before reservation, or extend the time once you see the message, or maybe just save your work and leave the device if you no longer need it.

If you no longer need the device, you can close the window and a message will appear asking you if you want to cancel the reservation of the remaining time. Of course if you don't need it any more, then it will be unfair to keep the reservation (wasting the resources that other people may need). But if you want to keep the reservation, device will still be yours until the time expires or you free the remaining time later.

Notice that when you reserve a device, it will appear in "Your Reservations". If you move your mouse over it, you'll find the remaining time, the option to extend your reservation, and an option to cancel the reservation.

If you want to make a later reservation, you'll be redirected to a table showing all current/later reservations for all devices. Your reservation is the one in green and the others in red. If you click any free time slot for any device you'll be asked for confirmation.
This table also appears when you cancel a reservation.

That's it for this entry. I hope I could help. And I want to say that this service is really helpful and you should try it.

Pushups Counter using Adobe Flash Lite (Part 1)

2010-09-09T13:47:00.006+02:00

[stopped for a while()]

A friend of mine was talking about an iPhone app for counting pushups and how it was a success. At the same time I was introduced to the new world (it was new for me) of Adobe Flash Lite. So I thought about testing this Adobe thing and putting this app as a goal to apply what I learn.

I started to think about ways to sense the pushups:

Altitude: too complex for a small app.
Accelerometer: counting the pushups depending on changing the orientation of the device. Whether to put it on your back (stupid) or on the arm.

And I found some ideas on the web:

Touching the screen with your nose (believe me, it's a real app).
Using the iPhone proximity sensor to detect your chest.

Here are some videos:

So, my desired app will be using the accelerometer. What about my sources to learn Adobe Flash Lite?

.... Plus any video or website that can help.

I found a video on Vimeo that demonstrates accessing the accelerometer. I guess it can help.

Platform Services and the Accelerometer from Adobe Flash Lite on Vimeo.

So, here I go.

File-based Logging in Qt

2010-08-31T17:01:00.004+02:00

[This entry is a refinement of an article I found here]

Testing applications for mobiles or embedded systems is very hard most of the time because I'm not always able to debug the application on the device. One solution was to write some debugging lines inside the program, and when the program passes each of these lines, the line will be written to a text file. Then I can simply open the text file and see how the application went or where it stopped.

Here it how it goes:

- Before the main(), I write:

using namespace std;
ofstream logfile;

void SimpleLoggingHandler(QtMsgType type, const char *msg)
{
    switch (type) {
        case QtDebugMsg:
            logfile << QTime::currentTime().toString().toAscii().data() << " Debug: " << msg << "\n";
            break;
        case QtCriticalMsg:
            logfile << QTime::currentTime().toString().toAscii().data() << " Critical: " << msg << "\n";
            break;
        case QtWarningMsg:
            logfile << QTime::currentTime().toString().toAscii().data() << " Warning: " << msg << "\n";
            break;
        case QtFatalMsg:
            logfile << QTime::currentTime().toString().toAscii().data() <<  " Fatal: " << msg << "\n";
            abort();
        }
    }

where each line of

logfile << QTime::currentTime().toString().toAscii().data() << " Debug: " << msg << "\n";

represents the format before each message I write. In this example I write the time, then the type of message, then the message.

- Then inside the main():

logfile.open("E:/myFile.txt", ios::app);
qInstallMsgHandler(SimpleLoggingHandler);

- Now at any class, if I want to write a message, I will just include:

#include <QDebug>

and write the line I want. For example:

qDebug()<< "[XmlClass] Receiving xml data from httpclient";

[I added class name between square brackets to know the class I am in]

Mobile Softkeys in Qt

2010-08-20T17:23:00.005+02:00

[Nokia Qt SDK v1.0 - 23 June 2010 ]

When programming for Symbian, it is essential to make use of the available buttons. Here is how to assign the left and right buttons.

//Left Button
QAction *okSoftKeyAction = new QAction(QString("Ok"), this);
okSoftKeyAction->setSoftKeyRole(QAction::PositiveSoftKey);
connect(okSoftKeyAction, SIGNAL(triggered()), this, SLOT(mySlot1()));
addAction(okSoftKeyAction);

//Right Button
QAction *cancelSoftKeyAction = new QAction(QString("Cancel"), this);
cancelSoftKeyAction->setSoftKeyRole(QAction::NegativeSoftKey);
connect(cancelSoftKeyAction, SIGNAL(triggered()), this, SLOT(mySlot2()));
addAction(cancelSoftKeyAction);

where the left button is the PositiveSoftKey and the right button is the NegativeSoftKey. And mySlot1() and mySlot2() are any slots I make or use.

Notes:

When trying this on the emulator of Nokia Qt SDK v1.0, I still see the original 'Options' and 'Exit' buttons. They are fake. When I tried it on my mobile (Nokia 5530) I could see the effects for real.
There are many articles in Nokia Forum and many other forums talking about softkeys but their code just doesn't compile. This is because the new Qt 4.7 is different. Here is their code:

[the setSoftkeys() method no longer exists in QWidget]

/* Create ok left softkey */
QAction* ok = new QAction(tr("OK"), this);
/* Let's make it ok softkey */
ok->setSoftKeyRole(QAction::OkSoftKey);
/* Connect action to dialogs accept slot,
* which will then emit accepted signal. */
connect(ok, SIGNAL(triggered()), this, SLOT(accept()));
 
/* Create cancel right softkey */
QAction* cancel = new QAction(tr("Cancel"), this);
/* Let's make it cancel softkey */
cancel->setSoftKeyRole(QAction::CancelSoftKey);
/* Connect action to dialogs reject slot,
* which will then emit rejected signal. */
connect(cancel, SIGNAL(triggered()), this, SLOT(reject()));
 
/* Set softkeys */
QList<QAction*> mySoftKeys;
mySoftKeys.append(ok);
mySoftKeys.append(cancel);
widget->setSoftKeys(mySoftKeys);

[special thanks to TamsS60]

Prayer Times Calculations: Pure C++ Code

2010-08-06T19:31:00.003+03:00

[18-January-2012 Update: I refined the code to make it easier and more elegant to use]
[06-July-2011 Update: I found this page http://praytimes.org/calculation#Implementation ]

This idea came to me when a friend of mine was asking for an 'offline database' for prayer times. I searched for algorithms to make my own database and almost all search results lead to the same algorithm. And all codes are divided into two categories: a simple but approximate one, and a complicated but precise one. I tried with the complicated one to understand it but it needs more time because of its nested functions and -unfortunately- it is not a priority right now. So I went with the easy one as a start.

One thing I noticed is that every person is trying to make the ultimate use of the framework he is working on (mostly dotNet). But come on, it is all about calculations. Why don't you make a code that can be easily converted from one language/platform to another? That's why I wanted to make that code. It has a major problem till now as it produces times later than my Egyptian calendar up to 5 minutes !!! Only later not earlier.

Anyways, here is the code, and I hope I can reach better results in the near future (in-sha'a Allah).

The parameters needed are:

Year/Month/Day of the desired day.
Longitude/Latitude/Time Zone of the desired place.
Fajr Twilight/ Esha Twilight which differ in calculations from one country to another.

Organization	Angle of the sun under the Horizon (Fajr)	Angle of the sun under the Horizon (Isha)	Region
University Of Islamic Sciences, Karachi	18 Degrees	18 Degrees	Pakistan, Bangladesh, India, Afghanistan, Parts of Europe
North America	15 Degrees	15 Degrees	Parts of the USA, Canada, Parts of the UK
Muslim World League	18 Degrees	17 Degrees	Europe, The Far East, Parts of the USA
Umm Al-Qura Committee	19 Degrees	90 minutes after the Sunset Prayer 120 minutes (in Ramadan only)	The Arabian Peninsula
Egyptian General Authority of Survey	19.5 Degrees	17.5 Degrees	Africa, Syria, Iraq, Lebanon, Malaysia, Parts of the USA

The only library used in this function was

#include <math.h>

to use the trigonometric functions (sin, cos,...)

The function takes the data of Year/Month/Day/Longitude/Latitude/TimeZone/FajrTwilight/IshaTwilight plus 6 references to double variables (Fajr/SunRise/Zuhr/Asr/Maghrib/Isha). These 6 variables are the ones to return data into. I also added some supporting functions to help in some number conversions (for example, Radians to Degrees and vise versa).

//convert Degree to Radian
double degToRad(double degree)
{
    return ((3.1415926 / 180) * degree);
}

//convert Radian to Degree
double radToDeg(double radian)
{
    return (radian * (180/3.1415926));
}

//make sure a value is between 0 and 360
double moreLess360(double value)
{
    while(value > 360 || value < 0)
    {
        if(value > 360)
            value -= 360;

        else if (value <0)
            value += 360;
    }

    return value;
}

//make sure a value is between 0 and 24
double moreLess24(double value)
{
    while(value > 24 || value < 0)
    {
        if(value > 24)
            value -= 24;

        else if (value <0)
            value += 24;
    }

    return value;
}

//convert the double number to Hours and Minutes
void doubleToHrMin(double number, int &hours, int &minutes)
{
    hours = floor(moreLess24(number));
    minutes = floor(moreLess24(number - hours) * 60);
}

void calcPrayerTimes(int year, int month, int day,
                     double longitude, double latitude, int timeZone,
                     double fajrTwilight, double ishaTwilight,
                     double &fajrTime, double &sunRiseTime, double &zuhrTime,
                     double &asrTime, double &maghribTime, double &ishaTime)
{
    double D = (367 * year) - ((year + (int)((month + 9) / 12)) * 7 / 4) + (((int)(275 * month / 9)) + day - 730531.5);

    double L = 280.461 + 0.9856474 * D;
    L = moreLess360(L);

    double M = 357.528 + (0.9856003) * D;
    M = moreLess360(M);

    double Lambda = L + 1.915 * sin(degToRad(M)) + 0.02 * sin(degToRad(2 * M));
    Lambda = moreLess360(Lambda);

    double Obliquity = 23.439 - 0.0000004 * D;
    double Alpha = radToDeg(atan((cos(degToRad(Obliquity)) * tan(degToRad(Lambda)))));
    Alpha = moreLess360(Alpha);

    Alpha = Alpha - (360 * (int)(Alpha / 360));
    Alpha = Alpha + 90 * (floor(Lambda / 90) - floor(Alpha / 90));

    double ST = 100.46 + 0.985647352 * D;
    double Dec = radToDeg(asin(sin(degToRad(Obliquity)) * sin(degToRad(Lambda))));
    double Durinal_Arc = radToDeg(acos((sin(degToRad(-0.8333)) - sin(degToRad(Dec)) * sin(degToRad(latitude))) / (cos(degToRad(Dec)) * cos(degToRad(latitude)))));

    double Noon = Alpha - ST;
    Noon = moreLess360(Noon);


    double UT_Noon = Noon - longitude;


    ////////////////////////////////////////////
    // Calculating Prayer Times Arcs & Times //
    //////////////////////////////////////////

    // 2) Zuhr Time [Local noon]
    zuhrTime = UT_Noon / 15 + timeZone;

    // Asr Hanafi
    //double Asr_Alt =radToDeg(atan(2+tan(degToRad(latitude - Dec))));

    // Asr Shafii
    double Asr_Alt = radToDeg(atan(1 + tan(degToRad(latitude - Dec))));
    double Asr_Arc = radToDeg(acos((sin(degToRad(90 - Asr_Alt)) - sin(degToRad(Dec)) * sin(degToRad(latitude))) / (cos(degToRad(Dec)) * cos(degToRad(latitude)))));
    Asr_Arc = Asr_Arc / 15;
    // 3) Asr Time
    asrTime = zuhrTime + Asr_Arc;

    // 1) Shorouq Time
    sunRiseTime = zuhrTime - (Durinal_Arc / 15);

    // 4) Maghrib Time
    maghribTime = zuhrTime + (Durinal_Arc / 15);


    double Esha_Arc = radToDeg(acos((sin(degToRad(ishaTwilight)) - sin(degToRad(Dec)) * sin(degToRad(latitude))) / (cos(degToRad(Dec)) * cos(degToRad(latitude)))));
    // 5) Isha Time
    ishaTime = zuhrTime + (Esha_Arc / 15);

    // 0) Fajr Time
    double Fajr_Arc = radToDeg(acos((sin(degToRad(fajrTwilight)) - sin(degToRad(Dec)) * sin(degToRad(latitude))) / (cos(degToRad(Dec)) * cos(degToRad(latitude)))));
    fajrTime = zuhrTime - (Fajr_Arc / 15);

    return;
}

So, if I take Cairo as an example:

Date: 18-1-2012
Longitude: 30.2
Latitude: 30
Time Zone: +2
Fajr Twilight: -19.5
Esha Twilight: -17.5

the function will be used like this:

double fajr, sunRise, zuhr, asr, maghrib, isha;
calcPrayerTimes(2012,1,18, 30.2, 30, 2, -19.5, -17.5, fajr, sunRise, zuhr, asr, maghrib, isha);

Note that these prayer times are still "double" and should be converted to a time format. I made the doubleToHrMin function (you can find it before the calcPrayerTimes fnction) which splits the number into Hours and Minutes. It takes the double and two references to int variables. Here is how to use it:

int hours, minutes;
doubleToHrMin(fajr, hours, minutes);

Now you have the prayer time as Hour/Minute to use it however you want.

So, in brief:
- I first add the above code block to my code, then use it whenever I want like this example:

double fajr, sunRise, zuhr, asr, maghrib, isha;
calcPrayerTimes(2012,1,18, 30.2, 30, 2, -19.5, -17.5,
                fajr, sunRise, zuhr, asr, maghrib, isha);

int hours, minutes;

doubleToHrMin(fajr, hours, minutes);
std::cout << "Fajr: " << hours << ":" << minutes << std::endl;

doubleToHrMin(sunRise, hours, minutes);
std::cout << "Sunrise: " << hours << ":" << minutes << std::endl;

doubleToHrMin(zuhr, hours, minutes);
std::cout << "Zuhr: " << hours << ":" << minutes << std::endl;

doubleToHrMin(asr, hours, minutes);
std::cout << "Asr: " << hours << ":" << minutes << std::endl;

doubleToHrMin(maghrib, hours, minutes);
std::cout << "Maghrib: " << hours << ":" << minutes << std::endl;

doubleToHrMin(isha, hours, minutes);
std::cout << "Isha: " << hours << ":" << minutes << std::endl;

I hope it is useful to someone looking for the pure algorithm with no framework dependencies, and I hope I come back to it one more time to see the problem of these extra resulting minutes.

Resources:

جمعية الفلك بالقطيف
Muslim Programmers & Designers Community
Tanzil.info (1),(2)
PrayTime.info
IslamCity.com
IslamWare.com

SQLite: 3.Qt and SQLite

2010-07-24T12:13:00.006+03:00

I mentioned before that SQLite is a C library. To use this library in C++ applications, you can use many wrappers. But since I'm going in the direction of Qt, I want to use the QtSql module. QtSql module uses some drivers to communicate with databases like SQLite, MySQL, Oracle ...

Or add

//in the *.pro file
QT += sql

and include

//in any class
#include <QtSql>

The process is very easy: Create a database object. Open it. Then execute some queries.

For this entry, I created a project to explain the basic features of QtSql. I will try to explain some parts of it, and you can download it and try to understand the complete code.

Viewing Table Contents:

To view table contents, you need a QSqlTableModel object. QSqlTableModel is a high-level interface for reading and writing database records from a single table.

A simple way to use it is like this:

After creating a database object, I create a QSqlTableModel object and connect it to my database. Then I name the table I want this object to represent.

QSqlDatabase *database = new QSqlDatabase();


//set database driver to QSQLITE
*database = QSqlDatabase::addDatabase("QSQLITE");


database->setDatabaseName("./phonebook.db");

QSqlTableModel *all_model = new QSqlTableModel(this, *database);


all_model->setTable("Contacts");

all_model->select();

Then I can use this model to preview the contents of this table in some 'item views' available in the GUI designers (List View, Tree View, Table View, Column View)

ui->contacts_tableView->setModel(all_model);

QSqlTableModel has some other methods like: sorting, filtering, editing a record...etc. For example, searching a database and viewing results can be implemented by filtering the current model:

//search database for a certain name
search_model->setFilter("Name = \'"+ui->search_lineEdit->text()+"\'");

Queries:

QSqlQuery is a class that provides a means of executing and manipulating SQL statements. Its simplest statement looks like this:

QSqlQuery query("delete from Contacts where Mobile = 1234");
query.exec();

The exec() method returns 'true' if query is successful, and 'false' if it fails.

To make a query containing some variables, you can do this:

QSqlQuery query ("insert into Contacts (Name, Mobile, City) values (:name, :mobile, :city)");
    query.bindValue(0, ui->add_name_lineEdit->text());
    query.bindValue(1, ui->add_mobile_lineEdit->text());
    query.bindValue(2, ui->add_city_lineEdit->text());

    if(!query.exec())
    {
        QMessageBox::warning(0,"Error", "Please check your entered data.");
        return;
    }

where 0, 1, and 2 are the positions of the variables :name, :mobile, and :city. You can also replace the positions by the variable names:

    query.bindValue(":name", ui->add_name_lineEdit->text());
    query.bindValue(":mobile", ui->add_mobile_lineEdit->text());
    query.bindValue(":address", ui->add_city_lineEdit->text();

Note: sometimes i needed to change the query depending on a certain condition. One way to do this is using the prepare() method:

    QSqlQuery query;

    if(ui->remove_name_radioButton->isChecked())
    {
         query.prepare("delete from Contacts where Name = \'" + ui->remove_lineEdit->text()+"\'");
    }
    else
    {
        query.prepare("delete from Contacts where Mobile = \'" + ui->remove_lineEdit->text()+"\'");
    }

    if(!query.exec())
    {
        QMessageBox::warning(0,"Error", "Please check your entered data.");
        return;
    }

The Complete Example:

Now, here is the complete example for Qt with SQLite. It is a phonebook application that views all the contacts (using QSqlTableModel and a Table View), searches for a specific contact (using the filter() method of QSqlTableModel), and adds or removes a contact (using the queries).

Test it and read the code carefully. You can ask me anything you want.

Download

Blog Example by Mahmoud Adly Ezzat is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

SQLite: 2.Administration Tool

2010-07-12T12:23:00.004+03:00

After making some operations on a SQLite database using terminal, it would be better to have an easier and a more convenient tool. I wanted a free and easy-to-use program and i found Lita.

Lita is a free SQLite database administration tool for Windows, MacOSX and Linux. Using Lita, you can:

Open, create, compact, manage SQLite databases
Create, rename, delete, and empty tables
Create, rename and delete columns
Create, modify and delete records
Encrypt or re-encrypt your databases
Run, import and export your custom SQL statements
Create and delete indices

Once I opened this program, I didn't need any tutorial to start using it. You should try it yourself.

SQLite: 1.Terminal Commands Tutorial

2010-07-08T22:53:00.005+03:00

SQLite is a C library that implements a database engine. It is a perfect choice for embedded systems because of its small size and big capabilities. It may have some missing features (click me) but it is still a good choice (click me).

I want to start with a nice tutorial that uses only a command-line program for accessing and modifying SQLite databases (sqlite-3_6_23_1.zip). This tutorial does not require any previous knowledge of SQL databases. And even if you know, I guess you will not get bored because these are short and divided videos, so you can jump through them or have a quick overlook.

Static Building for Qt Apps on Windows

2010-07-04T14:17:00.063+03:00

I have talked before about dynamic building (click me) and now is the time for the static building. This is a long process that has many steps but I have to share my knowledge for those who are interested because I didn’t find a page that goes throw the entire process in details.
The main reason for static building is collecting all the needed DLLs that you need in a single executable file (*.exe), so the target computer does not need to install any packages or programs.

The steps are as follows:
1-    Configuring Qt Creator for static building, and compiling it.
2-    Building your application project statically using the configured Qt Creator.

1-    Configuring Qt Creator for static building:
Unfortunately, the normal Qt Creator that you install is only configured for static building. So you have to do one of the following:

1.1-    Download the Qt-Everywhere project and build your own customized Qt Creator:
-    This is done by downloading the (qt-everywhere-opensource-src-4.6.3.zip)
-    Uncompress the file in a directory like C:\Qt\4.6.3
-    Use Visual Studio Command Prompt to browse to this folder (is should be containing a ‘configure’ file).
-    Assuming you have Visual Studio 2005 or 2008, configure this project for windows with a command like this from Visual Studio Command Prompt (not tested):

configure -platform win32-msvc2008 –static –release -nomake demos -nomake examples –opensource -confirm-license -no-exceptions

for more configure options: type

configure –help

or download this file.

This may take about 30 minutes, and when done you can type

nmake sub-src

then just relax and find something to do in the next two hours (give or take an hour)

1.2- If you have already installed Qt Creator on your PC:

You can reconfigure it to build statically by writing the following command in the ‘Qt Command Prompt’ (I prefer taking a copy and configuring it, so I use the original for developing and debuggingm, and the new one for the final build):

configure -static -release -no-exceptions -nomake demos -nomake examples –opensource -confirm-license

then when done after about 30 minutes or less, type

mingw32-make sub-src

then just relax and find something to do in the next two hours (give or take an hour)

Now you have a Qt Creator configured for static building.

2- Building your application project statically using the configured Qt Creator:

2.1 Create any Qt project you want, than add the following lines in the project (*.pro) file:

win32 {
      QMAKE_LFLAGS += -static-libgcc
      }

2.2 Now go to the Qt Command Prompt and browse to the folder of your application and type

C:\Qt\Qt-2010.01-static\qt\bin\qmake helloworld.pro

Where:

helloworld.pro is the project file of my Qt application.

qmake is the file used to create the Makefile.

C:\Qt\Qt-2010.01-static\qt\bin\ is the directory of qmake in the newly compiled Qt Creator.

2.3 Now write

mingw32-make

2.4 The statically built application can be found in the ‘Release’ folder in your project.

Some Comments:

1- Why bothering myself and doing all these steps? For me, nothing is wrong with adding the needed DLLs in the same folder with the dynamically built application.
2- There is this lovely warning that appears while configuring Qt:
WARNING: Using static linking will disable the use of plugins. Make sure you compile ALL needed modules into the library.
So I have to make sure that all the plugins that I may use in the future are available. (Click here for more:step3)

Example: Simple Map

Dynamically Built

Statically Built

Sources:

Building Qt Static (and Dynamic) and Making it Small with GCC, Microsoft Visual Studio, and the Intel Compiler

How to statically link Qt 4

Qt static linking and removing the mingw-dll Dependency

Removing dependencies for mingwm10.dll and libgcc_s_dw2-1.dll,static linking?

Make your entire Qt application work entirely from a single file

Dynamic Building for Qt Apps on Windows

2010-06-30T21:54:00.011+03:00

قبل التحدث عن كيفية بناء مشروع Qt , أريد أن أوضح الفرق بين شيئين: Debug & Release

Debug Version : يحتوي البرنامج الناتج على بعض الإضافات التي تساعد في عملية الـdebugging مثل مراقبة المتغيرات داخل البرنامج و معرفة أي خطوة داخل البرنامج يتم تنفيذها الآن.

Release Version : يحدث شيء مختلف هنا و هو Code Optimization. أي قد تتم بعض التعديلات على الكود الخاص بك للزيادة من سرعة البرنامج أو توفيرا للذاكرة المستخدمة أو..... (للمزيد) . نتيجة لذلك يكون البرنامج أكثر سرعة من الـDebug Version و أقل حجما و لكن قد تلاحظ بعض المشكلات نتيجة لعملية الـoptimization فيجب التأكد من ذلك بإعادة تجربة البرنامج بعد بنائه كـ release version .

طريقة البناء في Qt :

1- قم باختيار Build -> Set Build Configuration -> Release

(أو Build -> Open Build/Run Target Selector -> Desktop -> Release في إصدارة Nokia Qt SDK 1.0.1 )

2- قم بالبناء من خلال Build -> Build Project

3- الآن تجد البرنامج الناتج في مجلد Release داخل مجلد المشروع. و لكنه لن يعمل بعد

4- الآن هناك بعض الـDLLs التي يجب وضعها بجانب البرنامج كي يعمل. سوف نأخذ نسخة منها من مجلد Qt . على سبيل المثال: المجلد الذي سآخذ منه هو C:\Qt\2010.01\qt\bin (قد يختلف قليلا حسب الإصدار أو مكان تثبيت Qt )

الملفات التي سآخذها أولا هي:

libgcc_s_dw2-1.dll

mingwm10.dll

QtCore4.dll

هناك بعض الملفات الإضافية التي آخذها حسب الـModules التي اخترتها عند إنشائي للمشروع. فمثلا إذا كان مشروعي قد استخدم GUI Module فسأحتاج لـ QtGui4.dll, و إذا استخدمت XML Module فسأحتاج إلى QtXml4.dll .... و هكذا. لابد من ملاحظة شيء مهم وهو أن هناك ملفات باسم مشابه و لكن مضاف إليها حرف “d” مثل QtCored4.dll و QtGuid4.dll .. و هي خاصة بالـdebug version فلا يجب أن نخلط بينهم (الملفات الخاصة بالـDebug أكبر في الحجم من الـRelease عدة مرات).

كل هذه الملفات أضعها بجانب البرنامج في نفس المجلد لأضمن عمله على أي جهاز.

هناك طريقة أخرى لجمع هذه الملفات بداخل البرنامج تسمى Static Building, و سأتحدث عنها لاحقا إن شاء الله.

C++ for Beginners: 2/2

2010-06-29T15:04:00.005+03:00

هذا هو الجزء الثاني من C++ for Beginners و هدفه الأساسي التعريف ببعض الـ IDEs المستخدمة لإنشاء برامج C++ ذات واجهة رسومية GUI. لقد استخدمت اثنين بشكل أساسي و هما

Visual Studio

بالإضافة لمن رشّحوا استخدام NetBeans و Eclipse و لكن لم أستخدمهم بعد. لذلك سأكتفي بالمقارنة بين ما استخدمته.

Platform:

Visual Studio : Works only on Windows

Qt: Works on Windows, Linux, Mac, Symbian … You just recompile your project on that platform to make a copy for it.

But if you only develop on Windows, this piece of info is not important.

GUI Design:

I liked the GUI in Qt much more than Visual Studio, because it has many useful elements, a variety of 3^rd party classes, and a very very important feature called ‘Layout’. It means that if you change the size of program window, the design will still fit inside it.

Debugging:

The debugging in Visual Studio is easier when debugging very big programs. But for normal programs, both Visual Studio and Qt are fine.

IntelliSense (auto complete):

Both are fine, but Visual Studio has a more fancy one.

Event Handling:

Qt uses something called ‘Signals and Slots’ which makes event handling a lot easier than Visual Studio.

Documentation and Help:

Visual Studio is very popular, so there are a lot of forums that can help you. There are also lots of forums for Qt but not as much as Visual Studio.

For documentation, I found the documentation of Qt more helpful than the MSDN of Visual Studio

بالنسبة لي فأنا أفضّل Qt أكثر من Visual Studio... و لكن يمكنكم أن تختبروهما و أي IDE آخر تختارونه. ففي النهاية كل شخص يختار بناء على خبرات أو نقاط ذات اهتمام أكثر من الأخرى.

Websites to help:

Visual Studio

Eclipse

NetBeans

Qt Free Reference:

C++ GUI Programming with Qt 4, 1st Edition

C++ for Beginners: 1/2

2010-06-25T01:34:00.009+03:00

لغة C++ هي واحدة من أقوى لغات البرمجة التي يمكنك تعلّمها دون مجهود كبير. فأساسيات اللغة ليست بالكثيرة و بالتالي سريعة الفهم و التعلّم. برامجها تمتاز بالسرعة. لا تعتمد على نظام تشغيل محدد فيمكن استخدامها على Windows, Linux, Mac.. بدون اختلافات. كما أنها لا تزال تتطوّر منذ ظهورها و بالتالي فهي تنافس لغات البرمجة الأخرى.

هذه بعض المصادر التي أنصح باستخدامها لتعلّم أساسيات C++ , و هي أساسيات يمكن تعلّمها في أبسط أشكال البرامج: Console Applications (أي برامج تتعامل فقط من خلال نصوص تظهر للمستخدم أو يدخلها المستخدم)

cplusplus.com
مصدر مثالي لتعلّم C++ من الصفر. يتكون من حوالي 140 صفحة تشمل الأساسيات التي يجب تعلّمها و تحتوي على بعض الأمثلة الصغيرة للتوضيح. هي غير كافية للتمكن من اللغة و لكنها تشكّل صورة كاملة عن اللغة يمكن البناء عليها من مصادر أكبر.

cprogramming.com
هذا المصدر أيضا يبدأ من الصفر و لكنه يحتوى على العديد من المواضيع المتقدمة التي يمكن الدخول فيها بعد التمكن من الأساسيات. و هو أيضا يشرح باستخدام أمثلة بسيطة لتوضيح كل نقطة.

C Frequently Asked Questions
أنصح بتصفحه و لكن بعد تعلّم أساسيات C++ , لأنه يناقش بعض الأخطاء التي قد نقع فيها أثناء البرمجة. أجده مفيدا للتأكد من مدى فهمي لبعض النقاط في C++

ثم المصدر المفضّل لدي:
C++ How to Program
هذا الكتاب رغم كثرة صفحاتة و طول الشرح في كل نقطة في C++ و كثرة الأمثلة التي قد تبدو مملة (على الأقل بالنسبة لي), إلا أنه مثالي في الشرح. فهو لا يعرّفني على إحدى النقاط و لكنه يشرحها بالفصيل و باحتمالاتها المختلفة, بل أيضا أفضل ممارسات البرمجة لكل نقطة من حيث تجنّب الأخطاء و زيادة السرعة. و مع الكتاب تأتي اسطوانة بها جميع الأمثلة المذكورة بالمتاب لتوفير وقت إعادة كتابتها. كما أن النسخة الجديدة من الكتاب بها مواضيع مهمة تخص تطوير C++ و أسباب بقاء C++ قوية و مستخدمة بكثرة حتى الآن.

أي من المصادر السابقة أجده كافيا لتعلّم C++ (مع اختلاف درجات الإتقان و تغطية المواضيع الجديدة). و بمعرفة هذه الأساسيات, نكون مستعدين للإنشاء البرامج ذات الواجهة الرسومية التي نستخدمها في كل برامجنا, و التي سأتحدث عنها في المرة القادمة.

بعض البرامج التي يمكن استخدامها:
في هذه المرحلة من تعلّم C++ , لا داعى لاستخدام أي من البرامج الكبيرة مثل Visual C++, و لكن تكفينا برامج بسيطة مثل:

Dev-C++

Borland C++

Code:Blocks

المقدمة Introduction

2010-06-18T19:51:00.007+03:00

السلام عليكم و رحمة الله و بركاته

هذه هي أول مدونة لي في مجال تخصصي – و هو مجال الحاسبات و النظم - , السبب في إنشائها كان مشاركة ما أعرفه من علم و إن كان قليلا بالإضافة لتسجيل المستوى الذي أنا عليه كل فترة لأعرف مدى تقدمي و تكون سببا في دفعى للتقدم أكثر. هناك بعض الخطوط التي أحاول الالتزام بها, و منها:

ما أكتبه يجب أن أتأكد منه بنفسي, و بخاصة الأكواد.
المهم في العلم ليس مجرد التلقي , و إنما معرفة كيفية الوصول لهذا العلم و تطبيقه. و هذا هو الأسلوب الذي أحاول اتباعه في تعلّمي.
لا فائدة من إعادة كتابة بعض المواضيع التي أجدها, و لكن يمكنني تلخيص الموضوع أو خلاصة ما بحثت عنه مع وضع المصادر التي استخدمتها.
يمكنكم استخدام و توزيع ما أنشره - طالما لم أذكر غير ذلك - فمن حق الجميع أن يتعلّم.
التعليق على ما أكتبه يكون محل ترحيب شديد. لأنه أسلوب جيد لمعرفة أخطائي و تطوير أسلوبي.

أتمنى أن أكود مصدر إفادة من خلال هذه المدونة و في انتظار أرائكم ...... تابعونا :)

This is my first technical blog in my speciality, Computers and Systems. The reason for making it was sharing what I know, even if it was a little, in addition to leaving a record of my current level to observe my development and find a way to push me forward. There are some guidelines I'm trying to stick to:

I make sure of what I write, especially the codes.
Learning is not about materials or sources, but how to learn and apply. And this is the way I'm trying to apply in my learning.
There is no use of rewriting the topics I find, but I can summarize the topic or a summary of my search, aside with the resources I used.
You are free to use or distribute what I publish, unless I mention anything else. It is the right of everyone to learn.
Commenting on my posts is more than welcomed. Because it is a good way of knowing my mistakes and developing my style.

I hope I be useful through this blog, and waiting for your opinions ... stay tuned :)