android 使用广播监听网络状态

参考：http://blog.csdn.net/androidbluetooth/article/details/7199708

博客 http://blog.csdn.net/androidbluetooth/article/details/6860146 详细的粘贴了很多判断网络的方法。

网络状态发生变化的时候，系统会发出 android.net.conn.CONNECTIVITY_CHANGE .
下面是实现的 demo ：

package mark.zhang;import android.app.Service;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.net.ConnectivityManager;import android.net.NetworkInfo;import android.os.IBinder;import android.util.Log;public class ListenNetStateService extends Service {    private ConnectivityManager connectivityManager;    private NetworkInfo info;    private BroadcastReceiver mReceiver = new BroadcastReceiver() {        @Override        public void onReceive(Context context, Intent intent) {            String action = intent.getAction();            if (action.equals(ConnectivityManager.CONNECTIVITY_ACTION)) {                Log.d("mark", "网络状态已经改变");                connectivityManager = (ConnectivityManager)                                               getSystemService(Context.CONNECTIVITY_SERVICE);                info = connectivityManager.getActiveNetworkInfo();                  if(info != null && info.isAvailable()) {                    String name = info.getTypeName();                    Log.d("mark", "当前网络名称：" + name);                } else {                    Log.d("mark", "没有可用网络");                }            }        }    };    @Override    public IBinder onBind(Intent intent) {        return null;    }    @Override    public void onCreate() {        super.onCreate();        IntentFilter mFilter = new IntentFilter();        mFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);        registerReceiver(mReceiver, mFilter);    }    @Override    public void onDestroy() {        super.onDestroy();        unregisterReceiver(mReceiver);    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        return super.onStartCommand(intent, flags, startId);    }}

在 manifest 文件中需要加上一条权限：

 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

回头再看看关于 CONNECTIVITY_ACTION 的介绍，从 api 中，我们还可以得到一个信息：

通过 intent 可以获取一些 EXTRA，如 EXTRA_NO_CONNECTIVITY。

boolean b = intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, true);

更多信息可以参考 ConnectivityManager.

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在Android操作系统中，如何能够正确的判断我们所连接的网络是否断开恩？今天我们就针对这一应用技巧进行一个详细的分析。

public class ConnectionChangeReceiver extends BroadcastReceiver {           @Override           public void onReceive( Context context, Intent intent ) {               ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);               NetworkInfo activeNetInfo = connectivityManager.getActiveNetworkInfo();               NetworkInfo mobNetInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);               if ( activeNetInfo != null ) {                   Toast.makeText( context, "Active Network Type : " +                      activeNetInfo.getTypeName(), Toast.LENGTH_SHORT ).show();                   }               if( mobNetInfo != null ) {                   Toast.makeText( context, "Mobile Network Type : " +                      mobNetInfo.getTypeName(), Toast.LENGTH_SHORT ).show();                   }             }       }  

< !-- Needed to check when the network connection changes -->     < uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>     < receiver android:name="com.blackboard.androidtest.receiver.ConnectionChangeReceiver"                android:label="NetworkConnection">         < intent-filter>             < action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>         < /intent-filter>     < /receiver>