Android 按两次back键退出 -- 效率最高版

Java代码

01.private long exitTime = 0;   

02.   

03.@Override   

04.public boolean onKeyDown(int keyCode, KeyEvent event) {   

05.    if(keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN){   

06.                   

07.    if((System.currentTimeMillis()-exitTime) > 2000){   

08.        Toast.makeText(getApplicationContext(), "再按一次退出程序", Toast.LENGTH_SHORT).show();                                exitTime = System.currentTimeMillis();   

09.    }   

10.    else{   

11.        finish();   

12.        System.exit(0);   

13.        }   

14.                   

15.    return true;   

16.    }   

17.    return super.onKeyDown(keyCode, event);   

18.}