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