Newb--Q: HOW to DRAW with worker THREAD

[doubleslash]

Hi,
I'm writing a program to draw one circle at a time onto SurfaceView using a secondary thread. It runs fine, but I would see multiple circles at a time. Can you please help as I'm going insane trying to understand where the bug could be. Inside the class which implments Runnable, I have the run method continuously draw different circles and post to the surface one at a time (or at least I think so).

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Using java Syntax Highlighting

1. @Override
2.  
3. public void run(){
4.  
5. try {
6.  
7.                                 while(!done){
8.  
9. //done is set to be false so we can continuously draw onto the SurfaceView until quitJob() is called.
10.  
11.                                 //code to change drawing_r here
12.  
13.                                         synchronized(mholder){
14.  
15.                                                 c = mholder.lockCanvas();
16.  
17.                                                 c.drawCircle(center.x, center.y, drawing_r, mbrush);
18.  
19.                                                 mholder.unlockCanvasAndPost(c);
20.  
21.                                                 }
22.  
23.                                         Thread.sleep(2000);
24.  
25.                                        
26.  
27.                                 }
28.  
29.                         }catch (InterruptedException ex){}
30.  
31. }

Parsed in 0.032 seconds, using GeSHi 1.0.8.4

Inside the class which extends SurfaceView, I have the following resume and pause methods which are called by SurfaceCreated and SurfaceDestroyed, respectively.

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1.         public void resume(){
2.  
3.                 //start the background drawing job
4.  
5.                 if(jobThread != null){
6.  
7.                         pause();
8.  
9.                 }
10.  
11.                 job = new bckGrndJob(mholder.getSurfaceFrame().width(), mholder.getSurfaceFrame().height());
12.  
13.                 //task
14.  
15.                 jobThread = new Thread(job, "draw");
16.  
17.                 jobThread.start();
18.  
19.                
20.  
21.         }
22.  
23.         public void pause(){
24.  
25.                 //stop the thread/job
26.  
27.                 job.quitJob(); //this will set done to be true and allows the Runnable run method above to exit the while loop
28.  
29.                 if(jobThread != null){
30.  
31.                                 try {
32.  
33.                                         jobThread.join();
34.  
35.                                 } catch (InterruptedException e) {}
36.  
37.                 }
38.  
39.                 jobThread = null;
40.  
41.         }

Parsed in 0.032 seconds, using GeSHi 1.0.8.4

Thank you for looking.

[MrSnowflake]

Have you taken a look at the LunarLander sample?

[doubleslash]

Thanks for the reply. It turned out that I just needed to clear the canvas.