Android学习Android广播机制

在Android中实现播送，首先咱们要在Manifest.xml文件中配置一个<receiver/>标签，这个标签必须有一个android:name属性，值为继承自BroadcastReceiver类的接收器类！这个标签还有一个子标签为<intent-filter/>,这个标签很重要，是指定接收器须要接管哪种播送。另外，还有配置一个用户权限：<uses-permission/>,具体的值能够参考官网API文档。
另外一个比拟重要的步骤是必须有一个类继承自BroadcastReceiver类，并复写onReceiver办法，在该办法中解决接管到播送后须要解决的事件！
上面来看一个具体的例子，有助于更好的了解播送机制是怎么一回事。
UI局部就不说了，Activity上就加了一个按钮，点击后发送播送。接收器接管到播送后在终端输入一句话。
首先看AndroidManifest.xml文件：
 `
<?xml version=”1.0″ encoding=”utf-8″?>
<manifest xmlns:android=”http://schemas.android.com/apk/res/android&#8221;
            package=”com.gufengxiachen.broadcast”
            android:versionCode=”1″
            android:versionName=”1.0″>
        <uses-sdk android:minSdkVersion=”8″ />

        <application android:icon=”@drawable/icon” android:label=”@string/app_name”>
                <activity android:name=”.BroadCast”
                                    android:label=”@string/app_name”>
                        <intent-filter>
                                <action android:name=”android.intent.action.MAIN” />
                                <category android:name=”android.intent.category.LAUNCHER” />
                        </intent-filter>
                </activity>

<receiver android:name=”.MyBroadCastReceiver”>
<intent-filter>
<action android:name=”android.intent.action.EDIT”></action>
</intent-filter>

</receiver>
        </application>
    
        <uses-permission android:name=”android.permission.RECEIVE_SMS”></uses-permission>
</manifest>

 `
上面是Activity：
 `
package com.gufengxiachen.broadcast;

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 BroadCast extends Activity {
        /* Called when the activity is first created. /
private Button bound =null;
private Button unbound =null;
private Button sendBroadCast =null;
private SecondBroadCastReceiver sbr =null;

public static final String SMS_ACTION=”android.provider.Telephony.SMS_RECEVIER”;

        @Override
        public void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.main);
                bound = (Button)findViewById(R.id.bound);
                unbound = (Button)findViewById(R.id.unbound);
                sendBroadCast = (Button)findViewById(R.id.sendBroadCast);
                bound.setOnClickListener(new BoundListener());
                unbound.setOnClickListener(new UnboundListener());
                sendBroadCast.setOnClickListener(new SendBroadCast());
        }
        class SendBroadCast implements OnClickListener{
        @Override
        public void onClick(View v) {
        // TODO Auto-generated method stub
    
        Intent intent = new Intent(Intent.ACTION_EDIT);
        BroadCast.this.sendBroadcast(intent);
        }
        }
        
        class BoundListener implements OnClickListener{
        @Override
        public void onClick(View v) {
        // TODO Auto-generated method stub
        sbr = new SecondBroadCastReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction(SMS_ACTION);
        BroadCast.this.registerReceiver(sbr, filter);        
        }
        }
        
class UnboundListener implements OnClickListener{
    
        @Override
        public void onClick(View v) {
        // TODO Auto-generated method stub
        BroadCast.this.unregisterReceiver(sbr);
        }

        }
}

 
 `
最初是接收器类：
 `
package com.gufengxiachen.broadcast;

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

public class MyBroadCastReceiver extends BroadcastReceiver{
public MyBroadCastReceiver(){

}
@Override
public void onReceive(Context context, Intent intent) {

System.out.println(“message receiver”);
}
}

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