发送有序广播Ordered Broadcast

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class SortedBroadcast extends Activity {
  Button send;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sorted_broadcast);
    //获取程序中的send按钮
    send = (Button) findViewById(R.id.send);
    send.setOnClickListener(new OnClickListener() {

      @Override
      public void onClick(View v) {
        // 创建Intent对象
        Intent intent = new Intent();
        intent.setAction(broadcasttest.action.CRAZY_BROADCAST");
        intent.putExtra("msg", "简单的消息");
        //发送有序广播
        sendOrderedBroadcast(intent, null);
      }
    });
  }

}

对于有序广播而言,它会按优先级依次触发每个BroadcastReceiver的onReceive()方法。

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Toast;

public class MyReceiver1 extends BroadcastReceiver{

  @Override
  public void onReceive(Context context, Intent intent) {
    Toast.makeText(context, "接收到的Intent的Action为:"+
        intent.getAction()+"\n消息内容是:"+intent.getStringExtra("msg"),
        5000).show();
    //创建一个Bundle对象,并存入数据
    Bundle bundle = new Bundle();
    bundle.putString("first", "第一个BroadcastReceiver存入的信息");
    //将Bundle放入结果中
    setResultExtras(bundle);
    //取消Broadcast的继续传播
    abortBroadcast();
  }

}

上面的BroadcastReceiver不仅处理了它接收到的消息,而且向处理结果中存入了key为first的消息,这个消息将可以被第二个BroadcastReceiver解析出来。,不过最后一行代码用于取消广播,如果保持这条代码生效,那么优先级比MyReceiver1低的BroadcastReceiver都将不会被触发。

在AndroidManifest.xml文件中部署该BroadcastReceiver,并指定其优先级为20,配置片段如下:

<receiver android:name=".MyReceiver1">
  <intent-filter android:priority="20">
    <action android:name="broadcasttest.action.CRAZY_BROADCAST"/>
  </intent-filter>
</receiver>

接下来再为程序提供第二个BroadcastReceiver,这个BroadcastReceiver将会解析前一个BroadcastReceiver所存入的key为first的消息,

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Toast;

public class MyReceiver2 extends BroadcastReceiver{

  @Override
  public void onReceive(Context context, Intent intent) {
    Bundle bundle = getResultExtras(true);
    //解析前一个BroadcastReceiver所存入的key为first的消息
    String first = bundle.getString("first");
    Toast.makeText(context, "第一个Broadcast存入的消息为:"+first,5000).show();

  }

}

在AndroidManifest.xml文件中部署该BroadcastReceiver,并指定其优先级为0,配置片段如下:

<receiver android:name=".MyReceiver2">
  <intent-filter android:priority="0">
    <action android:name="broadcasttest.action.CRAZY_BROADCAST"/>
  </intent-filter>
</receiver>

上一篇:How Tomcat Works(八)


下一篇:win8.1镜像制作