Android - ImageView flickering by changing the Image (Bitmap) on it

Question

I have got a Image (Bitmap) on a ImageView, without flickering. When I change something with setPixel(x, y, COLOR_VALUE) , so some Pixels are changed on the ImageView, it begins to flicker, where I changed the Pixels.

public class Drawer extends ImageView {

private Bitmap someBitmap;

public void doSomeDrawing() {
    for (int i = 0; i < 100; i = i + 2) {
        someBitmap.setPixel(x, y, COLOR_VALUE);
    }
    setOnDraw();
}

public void setOnDraw() {
   this.setImageBitmap(someBitmap);
}

Answer 1

Try getting a copy of your bitmap and draw on it. Then recycle your old bitmap.

The problem here might also be that setting the pixel takes time and if you do this on the UI Thread, it will slow down your app and may cause flickering too. How much time does doSomething take ?