Android初级教程_按两次返回键退出程序和长按返回键退出程序-优快云博客

本文详细介绍了如何通过长按返回键与双击返回键来实现应用的快速退出功能，包括代码实现与具体步骤。通过自定义事件处理与延迟执行，用户可以方便地控制应用的关闭过程。

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以上两个功能主要是参考了一下博客的:

http://blog.youkuaiyun.com/chenshijun0101/article/details/7682210

http://blog.youkuaiyun.com/winlinking/article/details/6596455

方法一：

按两次返回键退出程序:

public class Exit {

	private boolean isExit = false;
	private Runnable task = new Runnable() {
		@Override
		public void run() {
			isExit = false;
		}
	};

	public void doExitInOneSecond() {
		isExit = true;
		HandlerThread thread = new HandlerThread("doTask");
		thread.start();
		new Handler(thread.getLooper()).postDelayed(task, 1000);
	}

	public boolean isExit() {
		return isExit;
	}

	public void setExit(boolean isExit) {
		this.isExit = isExit;
	}
}

Activity:

public class Back2FinishAppActivity extends Activity {
	Exit exit = new Exit();

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }
    
    
    
    @Override  
      public boolean onKeyDown(int keyCode, KeyEvent event) {  
        if (keyCode == KeyEvent.KEYCODE_BACK) {  
                pressAgainExit();  
                return true;  
                }  
    
          return super.onKeyDown(keyCode, event);  
      }  
      
    private void pressAgainExit() {  
            if (exit.isExit()) {  
                finish();  
            } else {  
                Toast.makeText(getApplicationContext(), "再按一次退出程序",  
                        Toast.LENGTH_SHORT).show();  
                exit.doExitInOneSecond();  
            }  
        }  
}

长按返回键退出程序:

public boolean dispatchKeyEvent(KeyEvent event)  
    {  
        int keyCode=event.getKeyCode();  
        switch(keyCode)  
        {  
            case KeyEvent.KEYCODE_BACK: {  
                 if(event.isLongPress())  
                 {  
                     this.stopService(intent);  
                     System.exit(0);  
                     return true;  
                 }else  
                 {  
                     return false;  
    
                 }  
            }    
        }  
        return super.dispatchKeyEvent(event);  
          
    }

方法二：