【Android学习】Android广播机制

在Android中实现广播,首先我们要在Manifest.xml文件中配置一个标签,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,这个标签很重要,是指定接收器需要接收哪种广播。另外,还有配置一个用户权限:,具体的值可以参考官方API文档。
另外一个比较重要的步骤是必须有一个类继承自BroadcastReceiver类,并复写onReceiver方法,在该方法中处理接收到广播后需要处理的事情!
下面来看一个具体的例子,有助于更好的理解广播机制是怎么一回事。
UI部分就不说了,Activity上就加了一个按钮,点击后发送广播。接收器接收到广播后在终端输出一句话。
首先看AndroidManifest.xml文件:
 `

            package="com.gufengxiachen.broadcast"
            android:versionCode="1"
            android:versionName="1.0">
        

        
                                                    android:label="@string/app_name">
                        
                                
                                
                        

                





        
    
        

 `
下面是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);
        }

        

        }
}

 
 `
最后是接收器类:
 `
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");
}
}

你可能感兴趣的:(android)