Android 项目中如何监听网络状态

   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");       }     }   };