[android-developers] canvas.drawBitmap draws over screen image instead of replacing screen image

I have some strange behaviour when repainting the screen with my live wallpaper.  I'm scaling an image and drawing it to the screen, but on each draw (as the image is scaled smaller than the previous draw), I can still see the previous image below the new image.

How do I clear the previous image out so that only the new scaled image is displayed?

This is my code:

private final Runnable mDraw = new Runnable() {

            public void run() {

                draw();

            }

        };

        void draw() {

        SurfaceHolder holder = getSurfaceHolder();

Canvas canvas = null;

try {

canvas = holder.lockCanvas();

if(canvas != null) {

this.paintScreen(canvas);

}

}finally {

if(canvas != null) {

holder.unlockCanvasAndPost(canvas);

}

}

mHandler.removeCallbacks(mDraw);

if (mVisible) {

mHandler.postDelayed(mDraw, 60000);

}

        }

Every minute my paintSurface function scales a bitmap (image loaded from resources), then uses canvas.drawBitmap to put the image on the screen.  As I understand from the documentation, holde.lockCanvas()is not supposed to contain the image currently on the screen and every pixel has to be drawn... this doesn't seem to be the case since the previous pixels are obviously under the new pixels.

Thanks,

J

(26 Sept '12 - 10:45 AM)

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