Search for Wifi networks

Question

I'm trying to search for available wifi networks but nothing happens

this is my code

After Executing my code no error occurs.

I'm new to using BroadcastReceiver and I think that the problem in registering the Receiver.

public class MainActivity extends AppCompatActivity {

public class WifiReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {

        wifilist = wifi.getScanResults();

        txt.setText(wifilist.get(0).toString());

    }
}

WifiManager wifi;
WifiReceiver receiver;
List<ScanResult> wifilist;

String result = "";

TextView txt;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    txt = (TextView) findViewById(R.id.txt) ;

    wifi = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);

    if(!wifi.isWifiEnabled())
    {
        Toast.makeText(getApplicationContext(), "Wifi is Disabaled .. enabled it", Toast.LENGTH_LONG ).show();
        boolean b = wifi.setWifiEnabled(true);
    }



    receiver = new WifiReceiver();
    registerReceiver(receiver, new 
IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
wifi.startScan();


}

@Override
protected void onResume() {

    registerReceiver(receiver, new 
IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));

    super.onResume();
}

@Override
protected void onPause() {

    unregisterReceiver(receiver);

    super.onPause();
}


}

i made the TextView named txt show just the first network but it's name doesn't change