Android四大应用组件之BroadcastReceiver篇

总结自Android四大应用组件之BroadcastReceiver篇
Android四大应用组件之Activity篇https://www.jianshu.com/p/d22981a8ad0e
Android四大应用组件之Service篇https://www.jianshu.com/p/f7d57803b86e
Android四大应用组件之ContentProvider篇https://www.jianshu.com/p/5f783f3db22d
Android四大应用组件之BroadcastReceiver篇https://www.jianshu.com/p/e6283dec21c7

理论概述

系统级跨应用（进程间通信）的事件处理。
一个应用只要注册了对应的Receiver就会接受此广播

1.png 2.png

代码 (位于两个应用)

广播接收器类继承BroadcastReceiver

静态注册的

public class MyBroadcastReceiver extends BroadcastReceiver{
  public void onReceive(Context content,Intent intent){
    //处理广播
    //静态注册
    String ss=  intent.getStringExtra("action");
  }
 }

<receiver android:name="com.xxx1.MyBroadcastReceiver">
  <intent-filter>
    <action android:name="com.xxx1.MyR.action"/>
  </intent-filter>
</receiver>

发送广播

//一般广播
Intent intent = new Intent("com.xxx1.MyR.action");//和上面清单一致
intent.putExtra("action","go");
sendBroadcast(intent);

在发送端app发送时创建了MyBroadcastReceiver ，处理完就销毁，再次发送，再次创建MyBroadcastReceiver

动态注册

public class MyBroadcastReceiver extends BroadcastReceiver{
  public void onReceive(Context content,Intent intent){
    //处理广播
    //静态注册
    String ss=  intent.getStringExtra("action");
  }
 }

//activity：
MyBroadcastReceiver  re;

public void registBR(){
  if(re==null){
   re= new MyBroadcastReceiver ();
   //创建过滤器
    IntentFilter filter = new IntentFilter("com.xxx1.MyR.222");
    //注册receiver
    registerReceiver(re,filter);
  }else{
    //已经注册
  }
}

public void unregistBR(){
  if(re!=null){
    unregisterReceiver(re);
    re= null;
  } else{
    //  还没注册
  }
}

onDestroy(){
  super.onDestroy();
  unregistBR();
}

在动态调用方法时才创建MyBroadcastReceiver对象。而且不注销的话不销毁。

*一般来说动态注册比静态注册先接受到消息，因为静态注册先创建类再创建对象。动态直接创建对象。

3.png

有序广播

4.png

//一般广播
Intent intent = new Intent("com.xxx1.MyR.action");//和上面清单一致
intent.putExtra("action","go");
sendOrderBroadcast(intent);

<receiver android:name="com.xxx1.MyBroadcastReceiver">
  <intent-filter android:priority="2147483647">//优先级
    <action android:name="com.xxx1.MyR.action"/>
  </intent-filter>
</receiver>

if(isOrderedBroadcast()){
  abortBroadcast();//中断广播
}