[Ubuntu-ma] (sans objet)

[Nordin]

On 9-8-2010 15:27, H. Mohammed Amine wrote:
> great ! and what about using the threads ?
>    

Don't use threads for now, it's a horrible thing. Threads make things 
more complicated than needed. It depends on what you want.
As far as my experience goes (on Windows with C++ and C#), you can only 
access the user interface components like buttons and text fields from 
the main thread. That's the thread your application is started from. If 
you create another thread to do some calculation, than you can't just 
access the graphic object to do the drawings. I'm sure there are tricks 
to achieve that, but than you'll end up with lots of readings and 
experimenting to have good control over it.

Threads are useful if you have to wait a long time for a connection or 
data (from a serial port or from a tcp connection), in that case, 
instead of waiting all the time (which makes your UI not responding), 
it's better to do that in a separate thread and let the thread do the 
waiting. If something happens in that thread, you can inform the main 
thread with a message, signal or whatever construction they use in Java. 
In windows (using Visual C++) we have something like PostMessage() 
function call, to send a message from one thread to another. In C# I 
don't remember how to do that, but it's an ugly way to do that.

So my advise is, don't use it for something like an animation, timers 
are much better and very simple to use comparing to threads.
If you want to play with threads, we can do that next time together ;-). 
I want to write a simple chat app for Android (just for experimenting), 
we will use a thread for that (socket connection handling). If you can't 
wait, there is enough opensource code that works with threads in Java :).


> On Mon, Aug 9, 2010 at 1:24 PM, Nordin<bouchtaoui at gmail.com>  wrote:
>
>    
>> No problem,
>>
>> This construction is used a lot, because that keeps the user interface
>> responsive.
>> Imagine your animation is repeating forever in a loop, you want to be
>> able to stop with a stop button.
>> But because you're app is caught in a loop, you're unable to press stop,
>> this makes your app is not responding and eats a lot of CPU resource.
>> I don't know if you've seen a windows app freezing, well, that's the
>> same result you'll get with your application.
>>
>> Using a timer your app can respond on a stop button and everything is
>> fine ;-)
>> I hope you understand :)
>>
>>
>>
>> On 9-8-2010 14:48, H. Mohammed Amine wrote:
>>      
>>> nice idea ! thnx :) i'll try this
>>>
>>> On Mon, Aug 9, 2010 at 12:16 PM, Nordin<bouchtaoui at gmail.com>   wrote:
>>>
>>>
>>>        
>>>> On 9-8-2010 14:05, H. Mohammed Amine wrote:
>>>>
>>>>          
>>>>> No, No Compil Error i'm okeh till now !! i'm looking for how to anime
>>>>>            
>> it
>>      
>>>>>            
>>>> ! i
>>>>
>>>>          
>>>>> think something called timer
>>>>> thnx :)
>>>>>
>>>>>
>>>>>            
>>>> Yes, a timer would be the most logical way ;-)
>>>> I think you first try it by every time pushing on a button (manually)
>>>> and see if your animation does what it should do.
>>>> When everything goes fine, you can replace your button by a timer, that
>>>> triggers every 200 ms. In the timer handler you do the calculation and
>>>> than update your drawings.
>>>>
>>>>
>>>>          
>>>>> On Fri, Aug 6, 2010 at 3:57 PM, Gmail account<allali.ayoub at gmail.com
>>>>> wrote:
>>>>>
>>>>>
>>>>>
>>>>>            
>>>>>> @H Mohammed Amine ,*
>>>>>> *what is wrong with your code ?
>>>>>> did you have any compilation error ?
>>>>>>
>>>>>>
>>>>>>
>>>>>> AYYOUB Allali
>>>>>> JEE junior developer
>>>>>> +(212) 644 67 79 24
>>>>>>
>>>>>>
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>>>>>>
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