how to get list of wifi with xamarian android app

Issue

i have created one mobile app that gets list of wifi and get inserts to database. here is my code:

using System;
using Android.App;
using Android.Content.PM;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using Android.Content;
using System.Collections.Generic;
using Android.Net.Wifi;
using System.Text;
using Java.Lang;
using Xamarin.Forms;
using StringBuilder = System.Text.StringBuilder;
using Menu = Android.Views.Menu;
using Xamarin.Essentials;
using System.Threading.Tasks;

namespace WifiApp
{
    public partial class MainPage : ContentPage
    {
        //as temp list by shalin gajjar
        //IEnumerable<string> _wifiService = new List<string>() {"aaa","bbb","ccc","ddd","ffff"};

        IEnumerable<string> _wifiService ;

        public MainPage()
        {
            InitializeComponent();
            var wcurrent = Connectivity.NetworkAccess.ToString();
            //var wprofiles = Connectivity.ConnectionProfiles;

            if (wcurrent == NetworkAccess.Internet.ToString())
            {
                networkkState.Text = "Network is available..";
            }
            else
            {
                networkkState.Text = "Network is not available..";
            }


            /*if (wprofiles.ToString().Contains(ConnectionProfile.WiFi.ToString()))
            {
                networkkState.Text = wprofiles.FirstOrDefault().ToString();
            }
            else
            {
                networkkState.Text = wprofiles.FirstOrDefault().ToString();
            }*/
        }

        public interface IWifi
        {
            Task<IEnumerable<string>> GetAvailableNetworksAsync();
        }
   public async void Btn1get_Clicked(object sender, EventArgs e)
        {

            _wifiService = null;
            _wifiService = await DependencyService.Get<IWifi>().GetAvailableNetworksAsync();
            wifilist.ItemsSource = _wifiService;
        }
    }
}

and another most imp class :

using System;
using Android.App;
using Android.Content.PM;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using Android.Content;
using System.Collections.Generic;
using Android.Net.Wifi;
using System.Text;
using Java.Lang;
using Xamarin.Forms;
using StringBuilder = System.Text.StringBuilder;
using Menu = Android.Views.Menu;
using System.Timers;
using System.Threading;
using System.Threading.Tasks;

namespace WifiApp.Droid
{
    [Activity(Label = "WifiApp", Icon = "@mipmap/icon", Theme = "@style/MainTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation | ConfigChanges.UiMode | ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize )]
    public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            TabLayoutResource = Resource.Layout.Tabbar;
            ToolbarResource = Resource.Layout.Toolbar;

            base.OnCreate(savedInstanceState);

            Xamarin.Essentials.Platform.Init(this, savedInstanceState);
            global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
            LoadApplication(new App());
        }
        public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
        {
            Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);

            base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }

    public class Wifi : MainPage.IWifi
    {
        private Context context = null;

        public Wifi()
        {
            this.context = Android.App.Application.Context;
        }

        [Obsolete]
        public async Task<IEnumerable<string>> GetAvailableNetworksAsync()
        {
            IEnumerable<string> availableNetworks = null;

            // Get a handle to the Wifi
            var wifiMgr = (WifiManager)context.GetSystemService(Context.WifiService);
            var wifiReceiver = new WifiReceiver(wifiMgr);

            await Task.Run(() =>
            {
                // Start a scan and register the Broadcast receiver to get the list of Wifi Networks
                context.RegisterReceiver(wifiReceiver, new IntentFilter(WifiManager.ScanResultsAvailableAction));
                availableNetworks = wifiReceiver.Scan();
            });

            return availableNetworks;
        }

        [BroadcastReceiver(Enabled = true, Exported = false)]
        class WifiReceiver : BroadcastReceiver
        {
            private WifiManager wifi;
            private List<string> wifiNetworks;
            private AutoResetEvent receiverARE;
            private System.Threading.Timer tmr;
            private const int TIMEOUT_MILLIS = 20000; // 20 seconds timeout

            public WifiReceiver()
            {

            }
            public WifiReceiver(WifiManager wifi)
            {
                this.wifi = wifi;
                wifiNetworks = new List<string>();
                receiverARE = new AutoResetEvent(false);
            }

            [Obsolete]
            public IEnumerable<string> Scan()
            {
                tmr = new System.Threading.Timer(Timeout, null, TIMEOUT_MILLIS, System.Threading.Timeout.Infinite);
                wifi.StartScan();
                receiverARE.WaitOne();
                return wifiNetworks;
            }

            public override void OnReceive(Context context, Intent intent)
            {
                IList<ScanResult> scanwifinetworks = wifi.ScanResults;
                foreach (ScanResult wifinetwork in scanwifinetworks)
                {
                    wifiNetworks.Add(wifinetwork.Ssid);
                }

                receiverARE.Set();
            }

            private void Timeout(object sender)
            {
                // NOTE release scan, which we are using now, or we throw an error?
                receiverARE.Set();
            }
        }
    }
}

i m new in Xamarian and this task is important for me.

i can't getting list with it.. there is error occurs from Btn1get_Clicked that Object reference to an instance of an object. please help me .....

Solution

If you want to get the wifi list for Xamarin.From on Android Platform, it need to use the DependencyService to implement the function on each platform.

In Xamarin.Forms:

    public interface IGetWifiList
{
    ArrayList getWifiList();
}

Implementation on Android platform:

[assembly: Dependency(typeof(GetWifiList))]
namespace App14.Droid
{
public class GetWifiList : IGetWifiList
{
    public ArrayList getWifiList()
    {

        ArrayList myListrow = new ArrayList();


        var wifiMgr = (WifiManager)Android.App.Application.Context.GetSystemService(Context.WifiService);

       
        var wifiList = wifiMgr.ScanResults;

        foreach (var item in wifiList)
        {
            var wifiLevel = WifiManager.CalculateSignalLevel(item.Level, 100);
            myListrow.Add(($"Wifi Name: {item.Ssid} - Single: {wifiLevel}"));

        }
        return myListrow;

    }
}
}

Usage in Xamarin.Forms:

   var LIST= DependencyService.Get<IGetWifiList>().getWifiList();

Do not forget to add the permission:

permission.ACCESS_COARSE_LOCATION

Answered By - Wendy Zang - MSFT