Android SurfaceView/Canvas flickering after trying to clear it
- by Mark D
So I am trying to clear the Canvas using canvas.drawColor(Color.BLACK) but if I just call this once, the display flickers and displays the old drawing which should have been covered up by the drawColor.
Here is the important bits of my code -
public void update() {
//This method is called by a Thread
Canvas canvas = holder.lockCanvas(null);
if (canvas != null) {
onDraw(canvas);
}
holder.unlockCanvasAndPost(canvas);
}
@Override
protected void onDraw(Canvas canvas) {
if (toClear) {
canvas.drawColor(Color.BLACK);
//if this is not set to change back to false, it does not flicker
toClear = false;
}
//Draw some objects that are moving around
}
public void clearScreen() {
//This method is called when the user pressed a button
toClear = true;
}
After Googling around a litte, I heard about double buffering but came to the understanding that lockCanvas() and unlockCanvasAndPost() should handle this for me. What is going wrong here?
