【Android】BroadCast广播机制应用与实例

如何编写广播接收器

第一步：需要继承BroadcastReceiver类，覆写其中的onReceive()方法. 

 class MyBroadcastReceiver extends BroadcastReceiver {
      //接收到广播会被自动调用
     @Override
     public void onReceive (Context context, Intent intent) {
         //从Intent中获取action
         …your code here…
     }
 }

第二步：定义好广播接收器还不行，必须向系统注册以便让其知道该接收器可以处理哪些广播事件。

常见方式是采用静态注册,修改MENIFEST.xml文件, 在中加入receiver标签.

 <application>
     <activity name=""/>
     <receiver android:name=".MyBroadcastReceiver">

         <intent-filter>
             <action android:name="com.app.bc.test"/>
         intent-filter>
     receiver>
 application>

第三步：此时我们可以发送一个广播事件出去，代码如下:

 Intent intent = new Intent(“com.app.bc.test”);
 sendBroadcast(intent);//发送广播事件

动态注册广播接收器

在某个Activity中,我们可以用代码来实现动态注册：

 //生成一个BroadcastReceiver对象
 SMSReceiver  smsReceiver = new SMSReceiver();
 //生成一个IntentFilter对象
 IntentFilter filter = new IntentFilter();
 filter.addAction(“android.provider.Telephony.SMS_RECEIVED”);
 //将BroadcastReceiver对象注册到系统当中
 //此处表示该接收器会处理短信事件
 TestBC1Activity.this.registerReceiver(smsReceiver, filter);

静态注册和动态注册的区别

1)静态注册：在AndroidManifest.xml注册，android不能自动销毁广播接收器，也就是说当应用程序关闭后，还是会接收广播。
2)动态注册：在代码中通过registerReceiver()手工注册.当程序关闭时,该接收器也会随之销毁。当然，也可手工调用unregisterReceiver()进行销毁。

操作小结

静态注册的步骤：

定义广播接收器,继承BroadcastReceiver类,覆写onReceive函数.
在xml文件中注册监听器,定义Intent-Filter中感兴趣的action操作.
使用sendBroadCast向系统发送对其感兴趣的广播接收器中.

动态注册的步骤：

 SMSReceiver  smsReceiver = new SMSReceiver();
 IntentFilter filter = new IntentFilter();
 filter.addAction(“android.provider.Telephony.SMS_RECEIVED”);
 TestBC1Activity.this.registerReceiver(smsReceiver, filter);

(无需在配置文件中注册接收器)

应用实例

 package com.app.test02;

 import android.app.Activity;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.os.Bundle;
 import android.view.View;
 import android.view.View.OnClickListener;

 public class BroadCastActivity1 extends Activity{
     Intent intent = new Intent();
     BroadCastTest1 bCastTest1 = new BroadCastTest1();
 //  BroadCastTest11 bCastTest11 = new BroadCastTest11();
 //  BroadCastTest111 bCastTest111 = new BroadCastTest111();
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         // TODO Auto-generated method stub
         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_bc1);
         //静态注册
         findViewById(R.id.button1).setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v) {
                 // TODO Auto-generated method stub
                 intent.setAction("bc.test101");
                 intent.putExtra("name", "静态的");
                 sendBroadcast(intent);
 //              sendOrderedBroadcast(intent, null);
             }
         });
         //动态注册
         findViewById(R.id.button2).setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v) {
                 // TODO Auto-generated method stub

                 IntentFilter intentFilter = new IntentFilter();
                 intentFilter.addAction("bc.test102");

                 BroadCastActivity1.this.registerReceiver(bCastTest1, intentFilter);

                 intent.setAction("bc.test102");
                 intent.putExtra("name", "动态的");
                 sendBroadcast(intent);
 //              sendOrderedBroadcast(intent, null);
             }
         });

         findViewById(R.id.button3).setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v) {
                 // TODO Auto-generated method stub
                 unregisterReceiver(bCastTest1);
                 finish();
             }
         });
     }
 }

广播类

 package com.app.test02;

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

 public class BroadCastTest1 extends BroadcastReceiver{
     @Override
     public void onReceive(Context context, Intent intent) {
         // TODO Auto-generated method stub
         String name = intent.getStringExtra("name");

         Toast.makeText(context, "广播1：" + name, 1000).show();
         System.out.println(1);
     }
 }

AndroidManifest.xml

 <receiver android:name=".BroadCastTest1">
     <intent-filter android:priority="3">
         <action android:name="bc.test101"/>
     intent-filter>
 receiver>

布局文件

 xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical"
     android:background="#fff"
     android:padding="10dp">

     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:orientation="vertical"
         android:gravity="center_horizontal" >

         <Button
             android:id="@+id/button1"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="静态注册广播" />

         <Button
             android:id="@+id/button2"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="动态注册广播" />

         <Button
             android:id="@+id/button3"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="退出" />

     LinearLayout>

 LinearLayout>