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BroadcastReceiver的使用,动态注册和注销,优先级和中断控制

时间:2016-07-02 11:50:47      阅读:250      评论:0      收藏:0      [点我收藏+]

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BroadcastReceiver:

BroadcastReceiver(广播接收器)是Android中的四大组件之一,用来通知某些事件的相关信息,如下载完成,设置改变等。

 

默认的BroadcastReceiver状态(新建完未更改任何设置)的简单使用方法:

1.通过new Intnet(MainActivity.this,MyReceiver.class)来启动指明的广播对象,(当manifests中注册了此BroadcastReceiver才能通过这种方法启动)

2.Intent可以通过intent.putExtra()方法携带一些信息,将这些信息传递给Broadcast

启动代码:

Intent i = new Intent(MainActivity.this,MyReceiver.class);
i.putExtra("data","testing");
sendBroadcast(i);

 

动态注册和注销:

在新建BroadcastReceiver时,IDE默认在manifests文件中给BroadcastReceiver注册,当manifests文件中删除了它的注册信息的时候,可以在BroadcastReceiver中添加public static final action = "包名.Intent.action.actionName"),然后通过new Intent(BroadcastReceiverName.action)来启动未注册的BroadcastReceiver)。

注册方法:

//在BroadcastReceiver中需要添加,用于启动BroadcastReceiver
public static final String action = "程序包名.intent.action.MyReceiver";
//此注册方法的代码在Activity中
private MyReceiver receiver = null; if (receiver==null){   receiver = new MyReceiver(); registerReceiver(receiver,new IntentFilter(MyReceiver.action)); }

注销方法:

if (receiver!=null){
  unregisterReceiver(receiver);
   receiver = null;
}

 

同时向多个BroadcastReceiver发送信息的方法:

1.在manifests文件中为需要同时发送的BroadcastReceiver注册相同的启动action

2.通过Intent启动多个BroadcastReceiver相同的action,并向其发送信息,即能是所有相同action的BroadcastReceiver收到信息

manifests模块的注册代码:

<receiver
  android:name=".MyReceiver1"
  android:enabled="true"
  android:exported="true">

  <intent-filter>
//设置的action <action android:name="程序包名.intent.action.MyReceiver"/> </intent-filter> </receiver>
<receiver android:name=".MyReceiver"> <intent-filter>
//设置的action <action android:name="程序包名.intent.action.MyReceiver"/>
</intent-filter>
</receiver>

//启动代码同注册时

BroadcastReceiver的优先级和中断操作:

BroadcastReceiver在未设置优先级的时候,同时发送信息的话,先在manifests文件中注册的BroadcastReceiver先收到信息,若是设置了优先级信息,那么优先级数值越大,优先级越高,优先级越高就先执行。

注:优先级在manifests文件中设置

在manifests文件中设置优先级的代码:

<receiver
 android:name=".MyReceiver1"
 android:enabled="true"
 android:exported="true">

 <intent-filter
 android:priority="9">    //设置MyReceiver1的优先级为9
 <action android:name="andrew.com.broadcastreceiverdemo.intent.action.MyReceiver"/>
 </intent-filter>
</receiver>
<receiver android:name=".MyReceiver">
<intent-filter android:priority="10">    //设置MyReceiver的优先级为10 <action android:name="andrew.com.broadcastreceiverdemo.intent.action.MyReceiver"/> </intent-filter>
</receiver>

//在设置对应的优先级后,MyReceiver会先接收到信息

 

BroadcastReceiver的中断操作:

在BroadcastReceiver存在接收优先级的时候,先接收到信息的BroadcastReceiver可以选择中断此广播,让优先级低于自己的BroadcastReceiver无法再接收到此次广播。

中断广播继续传递的代码:

 @Override
    public void onReceive(Context context, Intent intent) {
        abortBroadcast();    //在这里中断此次广播
    }

注:

若是有中断广播的操作,那么启动广播传递的方式不能是sendBroadcast()方法,使用sendBroadcast()发送的广播在接收时被中断,程序会出现错误。

要使中断广播的操作正常运行,需要使用sendOrderedBroadcast()方法。

 

BroadcastReceiver的使用,动态注册和注销,优先级和中断控制

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原文地址:http://www.cnblogs.com/thinfog/p/5635004.html

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