@Override public boolean onKeyDown(int keyCode, KeyEvent event) { switch (keyCode) { case KeyEvent.KEYCODE_HOME: moveTaskToBack(true); break; case KeyEvent.KEYCODE_MENU: if (!OPEN) { if (VISIBLE) { rightLowerButton.setVisibility(View.INVISIBLE); } else { rightLowerButton.setVisibility(View.VISIBLE); } paintView.isFocusable(); VISIBLE = !VISIBLE; } break; case KeyEvent.KEYCODE_VOLUME_UP: paintView.ReDoORUndo(true); break; case KeyEvent.KEYCODE_VOLUME_DOWN: paintView.ReDoORUndo(false); break; } return true; }