Android 按兩下退出的方法

Android 按兩下退出的方法

//在視圖創建時，把視圖添加到列表中
protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(...);
	XXXApplication.getInstance().AddActivity(this);
	
	...
｝


//退出代碼
private long exitTime = 0;
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if(keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN){   
        if((System.currentTimeMillis()-exitTime) > 2000){  
        	Toast.makeText(Login.this, "再按一次退出程序", Toast.LENGTH_SHORT).show();
            exitTime = System.currentTimeMillis(); 
        } else {
            XXXApplication.getInstance().exit();
        }
        return true;   
    }
    return super.onKeyDown(keyCode, event);
}
//XXXApplication.java
//

//聲明一個視圖列表
private List activityList = new LinkedList();
//聲明一個應用實例
private static XXXApplication instance;

//構造方法
public XXXApplication(){
		
}

//獲得實例方法
public static XXXApplication getInstance()
{
	if (instance==null){
		instance = new XXXApplication();
	}
	return instance;
}

//添加Activity到容器中
public void AddActivity(Activity activity){
	activityList.add(activity);
}
	
//退出。遍歷所有Activity並finish
public void exit(){
	for(Activity activity:activityList)
	{
		activity.finish();
	}
	System.exit(0);
}