Android: BroadCast Receiver ScanWiFi

class WifiReceiver extends BroadcastReceiver { 
        public void onReceive(Context context, Intent intent) {
                   wifiList = mainWifi.getScanResults();
                   for (int i = 0; i < wifiList.size(); i++) {
                   ScanResult scanResult = wifiList.get(i);
                   Log.d("huyhungdinh", "Scanresult: " + scanResult.toString());
                   }
        }
}

WifiManager mainWifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiReceiver receiverWifi = new WifiReceiver();
registerReceiver(receiverWifi, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)); mainWifi.startScan();