android 判断网络是否断开

引用：http://wang-peng1.iteye.com/blog/557362

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>