【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.

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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<application></application>中加入receiver标签.

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<application>

<activity name=""/>

<receiver android:name=".MyBroadcastReceiver">

<!-- intent过滤器,指定可以匹配哪些intent, 一般需要定义action 可以是自定义的也可是系统的 -->

<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:

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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：

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//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：

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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

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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

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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

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<receiver android:name=".BroadCastTest1">

<intent-filter android:priority="3">

<action android:name="bc.test101"/>

</intent-filter>

</receiver>

布局文件

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<?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>