Android提高之BroadcastReceiver实例详解

前面几篇文章分别讨论了Activity和Service,本文就来讨论BroastcastReceiver,Broastcast是应用程序间通信的手段。BroastcastReceiver也是跟Intent紧密相连的,动态/静态注册了BroastcastReceiver之后,使用sendBroadcast把Intent发送之后,系统会自动把符合条件的BroastcastReceiver启动,这和嵌入式系统的中断类似。

本文所示实例代码主要演示了如何静态/动态注册BroastcastReceiver,向系统索取电量信息,以及枚举信息的字段等功能和。

程序运行截图如下所示:

上图是发送Intent至内部动态注册的BroadcastReceiver,接收到之后显示消息名称。动态注册BroadcastReceiver用到registerReceiver()。

上图是发送Intent至内部静态注册的BroadcastReceiver,接收到之后显示消息名称。静态注册比动态注册麻烦点,先新建一个类继承BroadcastReceiver,然后到AndroidManifest.xml 添加

<receiver android:name="clsReceiver2">
 <intent-filter>
 <action
  android:name="com.testBroadcastReceiver.Internal_2"/>
 </intent-filter>
</receiver>

第一个name是类名,第二个是action的名称。

上图是枚举Intent消息的字段,这个功能比较适合懒人,把收到的Intent消息的字段全部分解了,再看看哪个需要的,懒得记住。实现这部分的代码如下:

//当未知Intent包含的内容,则需要通过以下方法来列举
Bundle b=intent.getExtras();
Object[] lstName=b.keySet().toArray();

for(int i=0;i<lstName.length;i++)
{
 String keyName=lstName[i].toString();
 Log.e(keyName,String.valueOf(b.get(keyName)));
}

main.xml的代码如下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical" android:layout_width="fill_parent"
 android:layout_height="fill_parent">

 <Button android:id="@+id/Button01" android:layout_width="wrap_content"
 android:layout_height="wrap_content" android:text="发送至内部动态注册的BroadcastReceiver"></Button>
 <Button android:id="@+id/Button02" android:layout_width="wrap_content"
 android:layout_height="wrap_content" android:text="发送至内部静态注册BroadcastReceiver"></Button>
 <Button android:id="@+id/Button03" android:layout_width="wrap_content"
 android:layout_height="wrap_content" android:text="发送至系统BroadcastReceiver"></Button>
</LinearLayout>

testBroadcastReceiver.java的代码如下:

package com.testBroadcastReceiver;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class testBroadcastReceiver extends Activity {
  Button btnInternal1,btnInternal2,btnSystem;
  static final String INTENAL_ACTION_1 = "com.testBroadcastReceiver.Internal_1";
  static final String INTENAL_ACTION_2 = "com.testBroadcastReceiver.Internal_2";
  static final String INTENAL_ACTION_3 = "com.testBroadcastReceiver.Internal_3";
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    btnInternal1=(Button)this.findViewById(R.id.Button01);
    btnInternal1.setOnClickListener(new ClickEvent());
    btnInternal2=(Button)this.findViewById(R.id.Button02);
    btnInternal2.setOnClickListener(new ClickEvent());
    btnSystem=(Button)this.findViewById(R.id.Button03);
    btnSystem.setOnClickListener(new ClickEvent());
    //动态注册广播消息
 registerReceiver(bcrIntenal1, new IntentFilter(INTENAL_ACTION_1));
  }
  class ClickEvent implements View.OnClickListener{

 @Override
 public void onClick(View v) {
  if(v==btnInternal1)//给动态注册的BroadcastReceiver发送数据
  {
  Intent intent = new Intent(INTENAL_ACTION_1);
  sendBroadcast(intent);
  }
  else if(v==btnInternal2)//给静态注册的BroadcastReceiver发送数据
  {
  Intent intent = new Intent(INTENAL_ACTION_2);
  sendBroadcast(intent);
  }
  else if(v==btnSystem)//动态注册 接收2组信息的BroadcastReceiver
  {
  IntentFilter filter = new IntentFilter();//
     filter.addAction(Intent.ACTION_BATTERY_CHANGED);//系统电量检测信息
     filter.addAction(INTENAL_ACTION_3);//第三组自定义消息
  registerReceiver(batInfoReceiver, filter);
  
  Intent intent = new Intent(INTENAL_ACTION_3);
  intent.putExtra("Name", "hellogv");
  intent.putExtra("Blog", "http://blog.csdn.net/hellogv");
  sendBroadcast(intent);//传递过去
  }
 }
   
  }
  /*
   * 接收动态注册广播的BroadcastReceiver
   */
 private BroadcastReceiver bcrIntenal1 = new BroadcastReceiver() {
 
 public void onReceive(Context context, Intent intent) {
  String action = intent.getAction();
  Toast.makeText(context, "动态:"+action, 1000).show();
 }
 };
 private BroadcastReceiver batInfoReceiver = new BroadcastReceiver() {
 public void onReceive(Context context, Intent intent) {
  String action = intent.getAction();
  //如果捕捉到的action是ACTION_BATTERY_CHANGED
  if (Intent.ACTION_BATTERY_CHANGED.equals(action)) {
  //当未知Intent包含的内容,则需要通过以下方法来列举
  Bundle b=intent.getExtras();
  Object[] lstName=b.keySet().toArray();

  for(int i=0;i<lstName.length;i++)
  {
   String keyName=lstName[i].toString();
   Log.e(keyName,String.valueOf(b.get(keyName)));
  }
  }
  //如果捕捉到的action是INTENAL_ACTION_3
  if (INTENAL_ACTION_3.equals(action)) {
  //当未知Intent包含的内容,则需要通过以下方法来列举
  Bundle b=intent.getExtras();
  Object[] lstName=b.keySet().toArray();
  for(int i=0;i<lstName.length;i++)
  {
   String keyName=lstName[i].toString();
   Log.e(keyName,b.getString(keyName));
  }
  }
 }
 };
}

clsReceiver2.java的代码如下:

package com.testBroadcastReceiver;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;
/*
 * 接收静态注册广播的BroadcastReceiver,
 * step1:要到AndroidManifest.xml这里注册消息
 *  <receiver android:name="clsReceiver2">
  <intent-filter>
  <action
   android:name="com.testBroadcastReceiver.Internal_2"/>
  </intent-filter>
 </receiver>
 step2:定义消息的字符串
 step3:通过Intent传递消息来驱使BroadcastReceiver触发
 */
public class clsReceiver2 extends BroadcastReceiver{
 @Override
 public void onReceive(Context context, Intent intent) {
 String action = intent.getAction();
 Toast.makeText(context, "静态:"+action, 1000).show();
 }
}

感兴趣的朋友可以调试运行该实例,希望能够对大家的Android项目开发起到一点帮助作用。