IllegalArgumentException in unlockCanvasAndPost (android live wallpaper)

Question

I've created my first live wallpaper implementing drawing in a separate thread. So now I have a WallpaperService and my WallpaperPainter who does the job. The problem is that I getting a IllegalArgumentException in unlockCanvasAndPost method on some of devices (Samsung Note is the one). I've read all recomendations I could find but couldn't fix that bug. Seems like the unlockCanvasAndPost is called when surface is destroyed so canvas is invalid. Here is the essential parts of code:

In wallpaper service:

    @Override
    public void onSurfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        super.onSurfaceChanged(holder, format, width, height);
        painting.setSurfaceSize(width, height);
    }

    @Override
    public void onSurfaceCreated(SurfaceHolder holder) {
        super.onSurfaceCreated(holder);
        painting.start();
    }

    @Override
    public void onSurfaceDestroyed(SurfaceHolder holder) {
        boolean retry = true;
        painting.stopPainting();
        while (retry) {
            try {
                painting.join();
                retry = false;
            } catch (InterruptedException e) { }
        }
        super.onSurfaceDestroyed(holder);
    }

In the painting thread:

public void stopPainting() {
    this.run = false;
    synchronized(this) {
        this.notify();
    }
}

public void run() {
    this.run = true;
    Canvas c = null;
    while (run) {
        try {
            synchronized (this) {
                Thread.sleep(50);
                c = this.surfaceHolder.lockCanvas();
                doDraw(c);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            if (c != null) {
                this.surfaceHolder.unlockCanvasAndPost(c); // << -- HERE IS THE PROBLEM
            }
        }
        // if pause...
        synchronized (this) {
            if (wait) {
                try {
                    wait();
                } catch (Exception e) { }
            }
        }
    }
}

Can anyone give me any clue what I'm doing wrong? I'm new both for Java and Android.

Answer 1

If error is: UnlockAndPost Failed, it means it unlocked no buffer. After this.surfaceHolder.unlockCanvasAndPost(c);
you can append
this.surfaceHolder.lockCanvas();
(sorry for my poor English proficiency)