BroadcastReceiver之实现锁屏、解锁例子

刺骨的言语ヽ痛彻心扉 2022-08-11 10:59 238阅读 0赞

好久没有写android的小例子了，由于前几天写了一篇关于Intent.Action的文章（[http://blog.csdn.net/ljphhj/article/details/38796739][http_blog.csdn.net_ljphhj_article_details_38796739]），有朋友私信问我关于ACTION\_SCREEN\_ON和ACTION\_SCREEN\_OFF还有ACTION\_USER\_PRESENT三个Action的用法，由于作为一个总结博文，当时并没有详细讲，**ACTION\_SCREEN\_ON和ACTION\_SCREEN\_OFF只能通过动态注册的方式（代码内context.register和unregister），而ACTION\_USER\_PRESENT则是动态、静态注册两种方式都可以。**下面我们通过这个锁屏、解锁相关的BroadcastReceiver来了解一下。

package cn.panghu.activitys;
    
    import com.example.broadcastsappdemo.R;
    
    import android.app.Activity;
    import android.app.KeyguardManager;
    import android.app.KeyguardManager.KeyguardLock;
    import android.content.BroadcastReceiver;
    import android.content.Context;
    import android.content.Intent;
    import android.content.IntentFilter;
    import android.os.Bundle;
    import android.os.PowerManager;
    import android.util.Log;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.view.ViewGroup.LayoutParams;
    import android.widget.Button;
    import android.widget.LinearLayout;
    import android.widget.TextView;
    import android.widget.Toast;
    
    public class ScreenLockedActivity extends Activity{
    	private ScreenBroadcastReceiver screenBroadcastReceiver = null;
    	private Context context = null;
    	private Button lockedScreenBtn = null;
    	@Override
    	protected void onCreate(Bundle savedInstanceState) {
    		super.onCreate(savedInstanceState);
    		context = getApplicationContext();
    		setContentView(R.layout.screen_lock_layout);
    	}
    	
    	@Override
    	protected void onResume() {
    		// TODO Auto-generated method stub
    		super.onResume();
    		
    		//注册这个广播
    		registerScreenBroadcastReceiver();
    	}
    	
    	private void registerScreenBroadcastReceiver() {
    		screenBroadcastReceiver = new ScreenBroadcastReceiver();
    		IntentFilter intentFilter = new IntentFilter();
    		intentFilter.addAction(Intent.ACTION_SCREEN_OFF);//当屏幕锁屏的时候触发
    		intentFilter.addAction(Intent.ACTION_SCREEN_ON);//当屏幕解锁的时候触发
    		intentFilter.addAction(Intent.ACTION_USER_PRESENT);//当用户重新唤醒手持设备时触发
    		context.registerReceiver(screenBroadcastReceiver, intentFilter);
    		Log.i("screenBR", "screenBroadcastReceiver注册了");
    	}
    	//重写广播
    	class ScreenBroadcastReceiver extends BroadcastReceiver{
    
    		@Override
    		public void onReceive(Context context, Intent intent) {
    			String strAction = intent.getAction();
    			if (Intent.ACTION_SCREEN_OFF.equals(strAction)){
    				//屏幕锁屏
    				Log.i("screenBR", "屏幕锁屏：ACTION_SCREEN_OFF触发");
    				Toast.makeText(context, "锁屏了", Toast.LENGTH_SHORT).show();
    			}else if (Intent.ACTION_SCREEN_ON.equals(strAction)){
    				//屏幕解锁(实际测试效果，不能用这个来判断解锁屏幕事件)
    				//【因为这个是解锁的时候触发，而解锁的时候广播还未注册】
    				Log.i("screenBR", "屏幕解锁：ACTION_SCREEN_ON触发");
    				Toast.makeText(context, "解锁了", Toast.LENGTH_SHORT).show();
    			}else if (Intent.ACTION_USER_PRESENT.equals(strAction)){
    				//屏幕解锁(该Action可以通过静态注册的方法注册)
    				//在解锁之后触发的，广播已注册
    				Log.i("screenBR", "屏幕解锁：ACTION_USER_PRESENT触发");
    				Toast.makeText(context, "解锁了", Toast.LENGTH_SHORT).show();
    			}else{
    				//nothing
    			}
    		}
    		
    	}
    	@Override
    	protected void onPause() {
    		// TODO Auto-generated method stub
    		super.onPause();
    		context.unregisterReceiver(screenBroadcastReceiver);
    		Log.i("screenBR", "screenBroadcastReceiver取消注册了");
    	}
    }

LogCat结果图：

![SouthEast][]

由于是静态注册的方式，所以大家可能会觉得那我要怎么让它长久地监听这锁屏、解锁屏幕的广播呢？

首先我们再次强调ACTION\_SCREEN\_ON和ACTION\_SCREEN\_OFF只能通过动态注册的方式（代码内context.register和unregister），而ACTION\_USER\_PRESENT则是动态、静态注册两种方式都可以。

那么我们的突破口便是：我们可以动态地注册一个关于屏幕解锁后（ACTION\_USER\_PRESENT）的广播者，并且在这个广播的onReceive方法中实现我们要做的一些操作。例如我们可以开启一个Service服务，用于注册我们所想要的这个Broadcast Receiver

1.在Service中定义receiver

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1.  **private** BroadcastReceiver mScreenFilterReceiver = **new** BroadcastReceiver() \{  
2.      **public** **void** onReceive(Context context, Intent intent) \{  
3.              **if** (intent.getAction().equals(Intent.ACTION\_SCREEN\_ON)) \{  
4.                  //做要求的处理  
5.              \}else if(intent.getAction().equals(Intent.ACTION\_SCREEN\_OFF))\{ 
6.  \}  
7.      \}  
8.  \};

2.在Service的onCreate中定义IntentFilter及注册receiver

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1.  IntentFilter ScreenFilter = **new** IntentFilter();  
2.  ScreenFilter.addAction(Intent.ACTION\_SCREEN\_ON);  
3.  ScreenFilter.addAction(Intent.ACTION\_SCREEN\_OFF);   
    
4.  registerReceiver(mScreenFilterReceiver, ScreenFilter);

3.在Service的onDestroy中要反注册这个receiver。

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1.  unregisterReceiver(mScreenFilterReceiver);  
2.

[http_blog.csdn.net_ljphhj_article_details_38796739]: http://blog.csdn.net/ljphhj/article/details/38796739
[SouthEast]: /images/20220810/bd51bf665e944504ae740523ba64a57b.png
[view plain]: http://blog.csdn.net/zhandoushi1982/article/details/8492389#
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[CODE_CODE]: https://code.csdn.net/snippets/214815
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