Android提高第六篇之BroadcastReceiver（广播接收者）

本文来自http://blog.csdn.net/hellogv/ ，引用必须注明出处！

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>

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)));

}

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>

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);

intent.setAction("com.testBroadcastReceiver.Internal_2")//声明action

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();

}

}