keyForCoords method for the PianoView on the SSaurel's Channel

PianoView.java

private Key keyForCoords(float x, float y) {
  for (Key k : blacks) {
    if (k.rect.contains(x,y)) {
      return k;
    }
  }

  for (Key k : whites) {
    if (k.rect.contains(x,y)) {
      return k;
    }
  }

  return null;
}

private void releaseKey(final Key k) {
  handler.postDelayed(new Runnable() {
    @Override
    public void run() {
      k.down = false;
      handler.sendEmptyMessage(0);
    }
  }, 100);
}

private Handler handler = new Handler() {
  @Override
  public void handleMessage(Message msg) {
    invalidate();
  }
};