public class MyActivity extends Activity {
  @Override
  public void onAttachedToWindow() {
    super.onAttachedToWindow();
    Window window = getWindow();
    // Eliminates color banding
    window.setFormat(PixelFormat.RGBA_8888);
  }
}

http://stuffthathappens.com/blog/2010/06/04/android-color-banding/

2.
setDither(true)