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Android学习笔记（十一）BroadcastReceiver动态注册、注销示例

在上一篇博文中简单介绍了一下BroadcastReceiver的相关知识点，本篇举一个在代码中动态的注册、注销BroadcastReceiver的栗子。

1、首先创建一个MyReceiver并继承BroadcastReceiver，既然要动态注册该receiver的话，就无需在AndroidManifest.xml中配置它了：

 1 public class MyReceiver extends BroadcastReceiver {  2     public static final String ACTION = "com.codingblock.receive.intent.action.MyReceiver";  3   4     public MyReceiver() {  5           6     }  7   8     @Override  9     public void onReceive(Context context, Intent intent) { 10         System.out.println("接收到的消息为：" + intent.getStringExtra("data")); 11     } 12 }

代码分析：上面代码中定义了一个静态变量ACTION，以方便程序指定该receiver。另外，从onReceive()方法的第二个参数intent可以获取到传递过来的数据。

2、布局文件如下，很简单，只有三个按钮：发送消息按钮、注册receiver按钮和注销receiver按钮。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:orientation="vertical" >  <Button   android:id="@+id/btn_send_receiver"   android:layout_width="wrap_content"   android:layout_height="wrap_content"   android:text="发送消息" />  <Button   android:id="@+id/btn_register_receiver"   android:layout_width="wrap_content"   android:layout_height="wrap_content"   android:text="注册receiver" />  <Button   android:id="@+id/btn_unregister_receiver"   android:layout_width="wrap_content"   android:layout_height="wrap_content"   android:text="注销receiver" /> </LinearLayout>

3、最后在MainActivity中测试一下

 1 public class MainActivity extends Activity implements OnClickListener {  2     private MyReceiver receiver = null;  3     @Override  4     protected void onCreate(Bundle savedInstanceState) {  5         super.onCreate(savedInstanceState);  6         setContentView(R.layout.activity_main);  7         findViewById(R.id.btn_send_receiver).setOnClickListener(this);  8         findViewById(R.id.btn_register_receiver).setOnClickListener(this);  9         findViewById(R.id.btn_unregister_receiver).setOnClickListener(this); 10     } 11  12     @Override 13     public void onClick(View v) { 14         switch (v.getId()) { 15         case R.id.btn_send_receiver: 16             Intent i = new Intent(MyReceiver.ACTION); 17             i.putExtra("data", "来自MainActivity的消息"); 18             sendBroadcast(i); 19             break; 20         case R.id.btn_register_receiver: 21             if (receiver == null) { 22                 System.out.println("注册receiver"); 23                 receiver = new MyReceiver(); 24                 registerReceiver(receiver, new IntentFilter(MyReceiver.ACTION)); 25             } 26             break; 27         case R.id.btn_unregister_receiver: 28             if (receiver != null) { 29                 System.out.println("注销receiver"); 30                 unregisterReceiver(receiver); 31                 receiver = null; 32             } 33             break; 34  35         default: 36             break; 37         } 38     } 39 }