废话不说，都是码农，直接上代码，相信你懂得。
private boolean isExit;//变量标示是否退出
//复写Activity的OnKeyDown方法
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0){
exit();
return false;
}
return super.onKeyDown(keyCode, event);
}
/**
* 程序退出方法
*/
public void exit() {
if (!isExit) {
isExit = true;
ToastUtil.showShort(getApplicationContext(), "再按 一次退出");
mHandler.sendEmptyMessageDelayed(0, 2000);
}else {
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
startActivity(intent);
System.exit(0);
}
}
/**
* 根据exit()方法中的消息而写的Handler
*/
Handler mHandler = new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
isExit = false;
}
};