物理按键及onKeyDown( )方法

    @Override    public boolean onKeyDown(int keyCode, KeyEvent event) {             //按下返回键       event.getKeyCode() = KeyEvent.KEYCODE_BACK;       //按下菜单键       event.getKeyCode() = KeyEvent.KEYCODE_MENU;        //按下HOME键       event.getKeyCode() = KeyEvent.KEYCODE_HOME;        //按下音量键       event.getKeyCode() = KeyEvent.KEYCODE_VOLUME_UP;                           = KeyEvent.KEYCODE_VOLUME_DOWN;        //按下电源键       event.getKeyCode() = KeyEvent.KEYCODE_POWER;                            //没有重复       event.getRepeatCount() = 0;        //默认返回true        return super.onKeyDown(keyCode, event);    }