Android提高篇1 之 BroadcastReceiver 应用程序间通信的手段

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，跟嵌入式系统的中断类似。

前面分别讨论了Activity和Service，这次就轮到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，跟嵌入式系统的中断类似。

本文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。本文运行截图如下：

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

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

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//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)));
                }
//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：

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<?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>
<?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">

testBroadcastReceiver.java的代码如下：

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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));
                }
            }
        }
    };

}
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：

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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();

    }
}

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/hellogv/archive/2010/11/10/5999170.aspx