Android 应用软件开发（十三）广播机制
广播机制：发送方不管接收方是否接收到数据，如何接收和处理
一、要想实现广播的接收，必须先创建一个类继承自BroadcastReceiver，复写其onReceive方法
二、在Manifest文件当中进行注册并设置action的过滤器，也可以在应用程序代码中注册
BroadcastReceiver的生命周期是，感兴趣的广播事件发生时创建对象，onReceive函数返回时销毁对象。
Intent 是action和data共同完成信息的携带的
如果BroadcastReceiver在Manifest中注册，则当应用程序关闭时，它依然会接收广播
<receiver android:name=".TestReceiver">
<intent-filter>
<action android:name="android.intent.action.EDIT"/>
</intent-filter>
</receiver>
在代码中注册，用于更新UI，Activity启动时注册，不可见时取消注册
Android 系统中内置的BroadcastActions
这些内置的actions可以在帮助文档的Intent类的常量中查到
下面分别给出两个例子（在manifest文件中注册广播接收器和在代码中注册广播接收器）
注意如果在代码中注册，则必须先在manifest文件中设置权限
TestBCActivity.java:
package mars.testBC;
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;
import android.widget.Button;
public class TestBCActivity extends Activity {
/** Called when the activity is first created. */
private Button sendButton;
private Button registerButton = null;
private Button unregisterButton = null;
private SMSReceiver smsReceiver = null;
private static final String SMS_ACTION = "android.provider.Telephony.SMS_RECEIVED";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
sendButton = (Button)findViewById(R.id.sendButton);
sendButton.setOnClickListener(new SendListener());
registerButton = (Button)findViewById(R.id.registerButton);
unregisterButton = (Button)findViewById(R.id.unregisterButton);
registerButton.setOnClickListener(new RegisterListener());
unregisterButton.setOnClickListener(new UnRegisterListener());
}
//例一
class SendListener implements OnClickListener{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
//生成Intent对象，挟带广播信息
Intent intent = new Intent();
//设置Action
intent.setAction(Intent.ACTION_EDIT);
//广播
TestBCActivity.this.sendBroadcast(intent);
}
}
//例二
class RegisterListener implements OnClickListener{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
smsReceiver = new SMSReceiver();
//设置过滤器
IntentFilter filter = new IntentFilter();
//添加过滤事件（短消息接收事件）
filter.addAction(SMS_ACTION);
//注册广播接收器
TestBCActivity.this.registerReceiver(smsReceiver, filter);
}
}
class UnRegisterListener implements OnClickListener{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
//解除绑定
TestBCActivity.this.unregisterReceiver(smsReceiver);
}
}
}
TestReceiver.java:
package mars.testBC;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class TestReceiver extends BroadcastReceiver {
public TestReceiver(){
System.out.println("TestReceive");
}
@Override
public void onReceive(Context arg0, Intent arg1) {
// TODO Auto-generated method stub
System.out.println("onReceive");
}
}
SMSReceiver.java:
package mars.testBC;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.SmsMessage;
public class SMSReceiver extends BroadcastReceiver {
SMSReceiver(){
System.out.println("SMSReceiver constructor");
}
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
Bundle bundle = intent.getExtras();
Object[] myOBJpdus = (Object[])bundle.get("pdus");
SmsMessage[] messages = new SmsMessage[myOBJpdus.length];
System.out.println(messages.length);
for(int i=0; i<myOBJpdus.length; i++)
{
messages[i] = SmsMessage.createFromPdu((byte[])myOBJpdus[i]);
System.out.println(messages[i].getDisplayMessageBody());
}
}
}
main.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello" />
<Button
android:id="@+id/sendButton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="start"/>
<Button
android:id="@+id/registerButton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="绑定"/>
<Button
android:id="@+id/unregisterButton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="解除绑定"/>
</LinearLayout>
Manifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="mars.testBC"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="4" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:label="@string/app_name"
android:name=".TestBCActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name=".TestReceiver">
<intent-filter>
<action android:name="android.intent.action.EDIT"/>
</intent-filter>
</receiver>
</application>
<!-- 设置权限 -->
<uses-permission
android:name="android.permission.RECEIVE_SMS">
</uses-permission>
</manifest>