WifiScannerActivity.java

package com.example.wifiscannertutorial;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

public class WifiScannerActivity extends AppCompatActivity {

    private WifiManager wifiManager;
    private ListView listView;
    private Button buttonScan;
    private int size = 0;
    private List<ScanResult> results;
    private ArrayList<String> arrayList = new ArrayList<>();
    private ArrayAdapter adapter;
    private BroadcastReceiver wifiReciver;
    private Context contex;

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

        buttonScan = findViewById(R.id.scnaBtn);

        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
        getApplicationContext().registerReceiver(wifiReciver, intentFilter);

        wifiReciver = new BroadcastReceiver(){
            @Override
            public void onReceive(Context context, Intent intent){
                results = wifiManager.getScanResults();
                unregisterReceiver(this);
                arrayList.add("Broad Cast Reciver Worked");
                Log.d("test", "Broad cast reciver worked");
                for(ScanResult scanResult : results){
                    Log.d("test", scanResult.SSID);
                    arrayList.add(scanResult.SSID + " - " + scanResult.capabilities);
                    adapter.notifyDataSetChanged();
                }

                adapter.notifyDataSetChanged();

            }
        };


        buttonScan.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view){
                scanWifi();
            }
        });

        listView = findViewById(R.id.wifiList);
        wifiManager = (WifiManager)getApplicationContext().getSystemService(Context.WIFI_SERVICE);
        contex = getApplicationContext();
        if(!wifiManager.isWifiEnabled()){
            Toast.makeText(this, "WiFi is disabled ... We need to enable it", Toast.LENGTH_SHORT).show();
            wifiManager.setWifiEnabled(true);
        }


        adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, arrayList);
        listView.setAdapter(adapter);
        scanWifi();
    }

    private void scanWifi() {
        arrayList.clear();
        adapter.notifyDataSetChanged();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
        registerReceiver(wifiReciver, intentFilter);
        wifiManager.startScan();
        Toast.makeText(this, "Scanning Wifi...", Toast.LENGTH_SHORT).show();
    }


}