Android 项目中如何监听网络状态

/** 
   * 有网络的广播 
   */ 
  BroadcastReceiver  connectionReceiver = new BroadcastReceiver() { 
    @Override 
    public void onReceive(Context context, Intent intent) { 
      ConnectivityManager connectMgr = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE); 
      NetworkInfo mobNetInfo = connectMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE); 
      NetworkInfo wifiNetInfo = connectMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI); 
      if (!mobNetInfo.isConnected() && !wifiNetInfo.isConnected()) { 
        Log.i("yuyahao", "断网了"); 
        Message msg = new Message(); 
        msg.what = DownLoadFileUtil.isNetConnectionError; 
        mHandler.sendMessage(msg); 
        // unconnect network 
      }else { 
        // connect network 
        Log.i(TAG, "有来网了"); 
      } 
    } 
  }; 

//有网络  的时候在注册网络监听广播 
      IntentFilter intentFilter = new IntentFilter(); 
      intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION); 
      registerReceiver(connectionReceiver, intentFilter); 
      showDialog(); 
      pool.execute(mUpdateUIThread);