android broastcast详解
16lz
2021-01-26
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
[xhtml] view plain copy print ?
- <receiverandroid: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:
[java] view plain copy print ?
- //当未知Intent包含的内容,则需要通过以下方法来列举
- Bundleb=intent.getExtras();
- Object[]lstName=b.keySet().toArray();
- for(inti=0;i<lstName.length;i++)
- {
- StringkeyName=lstName[i].toString();
- Log.e(keyName,String.valueOf(b.get(keyName)));
- }
main.xml的代码如下:
[xhtml] view plain copy print ?
- <?xmlversion="1.0"encoding="utf-8"?>
- <LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
- android:orientation="vertical"android:layout_width="fill_parent"
- android:layout_height="fill_parent">
- <Buttonandroid: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>
- <Buttonandroid: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>
- <Buttonandroid: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:
[java] view plain copy print ?
- packagecom.testBroadcastReceiver;
- importandroid.app.Activity;
- importandroid.content.BroadcastReceiver;
- importandroid.content.Context;
- importandroid.content.Intent;
- importandroid.content.IntentFilter;
- importandroid.os.Bundle;
- importandroid.util.Log;
- importandroid.view.View;
- importandroid.widget.Button;
- importandroid.widget.Toast;
- publicclasstestBroadcastReceiverextendsActivity{
- ButtonbtnInternal1,btnInternal2,btnSystem;
- staticfinalStringINTENAL_ACTION_1="com.testBroadcastReceiver.Internal_1";
- staticfinalStringINTENAL_ACTION_2="com.testBroadcastReceiver.Internal_2";
- staticfinalStringINTENAL_ACTION_3="com.testBroadcastReceiver.Internal_3";
- @Override
- publicvoidonCreate(BundlesavedInstanceState){
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- btnInternal1=(Button)this.findViewById(R.id.Button01);
- btnInternal1.setOnClickListener(newClickEvent());
- btnInternal2=(Button)this.findViewById(R.id.Button02);
- btnInternal2.setOnClickListener(newClickEvent());
- btnSystem=(Button)this.findViewById(R.id.Button03);
- btnSystem.setOnClickListener(newClickEvent());
- //动态注册广播消息
- registerReceiver(bcrIntenal1,newIntentFilter(INTENAL_ACTION_1));
- }
- classClickEventimplementsView.OnClickListener{
- @Override
- publicvoidonClick(Viewv){
- if(v==btnInternal1)//给动态注册的BroadcastReceiver发送数据
- {
- Intentintent=newIntent(INTENAL_ACTION_1);
- sendBroadcast(intent);
- }
- elseif(v==btnInternal2)//给静态注册的BroadcastReceiver发送数据
- {
- Intentintent=newIntent(INTENAL_ACTION_2);
- sendBroadcast(intent);
- }
- elseif(v==btnSystem)//动态注册接收2组信息的BroadcastReceiver
- {
- IntentFilterfilter=newIntentFilter();//
- 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);
- Intentintent=newIntent(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
- */
- privateBroadcastReceiverbcrIntenal1=newBroadcastReceiver(){
- publicvoidonReceive(Contextcontext,Intentintent){
- Stringaction=intent.getAction();
- Toast.makeText(context,"动态:"+action,1000).show();
- }
- };
- privateBroadcastReceiverbatInfoReceiver=newBroadcastReceiver(){
- publicvoidonReceive(Contextcontext,Intentintent){
- Stringaction=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
- Bundleb=intent.getExtras();
- Object[]lstName=b.keySet().toArray();
- for(inti=0;i<lstName.length;i++)
- {
- StringkeyName=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
- Bundleb=intent.getExtras();
- Object[]lstName=b.keySet().toArray();
- for(inti=0;i<lstName.length;i++)
- {
- StringkeyName=lstName[i].toString();
- Log.e(keyName,b.getString(keyName));
- }
- }
- }
- };
- }
clsReceiver2.java的代码如下:
[java] view plain copy print ?
- packagecom.testBroadcastReceiver;
- importandroid.content.BroadcastReceiver;
- importandroid.content.Context;
- importandroid.content.Intent;
- importandroid.widget.Toast;
- /*
- *接收静态注册广播的BroadcastReceiver,
- *step1:要到AndroidManifest.xml这里注册消息
- *<receiverandroid: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
- */
- publicclassclsReceiver2extendsBroadcastReceiver{
- @Override
- publicvoidonReceive(Contextcontext,Intentintent){
- Stringaction=intent.getAction();
- Toast.makeText(context,"静态:"+action,1000).show();
- }
- }
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