androidxamarin.formsandroid-wifi
How to get list of nearby WiFi Networks in Android Xamarin.Forms?
I have searched a lot of ways on this part, on how to get a self refreshing app when getting nearby WiFi networks. But nothing has ever worked for me. So I just have tried to check this resource> How to get available wifi networks and display them in a list in android
I tried to "convert" this code into Xamarin.Forms code, but there are some issues.
- How to create in App.xaml a TextView, then to populate it with data from MainActivity
- What Content View we can set here that the app will properly work. How to set as View like Resources->Layout-> Get Main Activity (and then to create Content view). Like
SetContentView(Resource.Layout.MainActivity);
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;
namespace MyApp.Droid
{
[Activity(Label = "MyApp", 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
{
static TextView mainText;
readonly Context context = Android.App.Application.Context;
static WifiManager mainWifi;
WifiReceiver receiverWifi;
static List<ScanResult> wifiList;
readonly System.Text.StringBuilder sb = new System.Text.StringBuilder();
protected override void OnCreate(Bundle savedInstanceState)
{
/* Default MainActivity Data--------------------------*/
base.OnCreate(savedInstanceState);
TabLayoutResource = Resource.Layout.Tabbar;
ToolbarResource = Resource.Layout.Toolbar;
global::Xamarin.Forms.Forms.Init(context, savedInstanceState);
/*-------------------------------------------------------*/
SetContentView();//Here must be set the main content view ???????
mainText = (TextView)FindViewById(Resource.Id.); // Here must get TextView Id ???????
mainWifi = (WifiManager)GetSystemService(Context.WifiService);
if (mainWifi.IsWifiEnabled == false)
{
// If wifi disabled then enable it
Toast.MakeText(context, "wifi is disabled..making it enabled", ToastLength.Long).Show();
mainWifi.SetWifiEnabled(true);
}
receiverWifi = new WifiReceiver();
RegisterReceiver(receiverWifi, new IntentFilter(WifiManager.ScanResultsAvailableAction));
mainWifi.StartScan();
char[] mine = "Starting Scan...".ToCharArray();
int length = mine.Length;
mainText.SetText(mine, 0, length);
Xamarin.Essentials.Platform.Init(this, savedInstanceState);
global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
LoadApplication(new App());
}
public override bool OnCreateOptionsMenu(IMenu menu)
{
menu.Add(0, 0, 0, "Refresh");
return base.OnCreateOptionsMenu(menu);
}
public override bool OnContextItemSelected(IMenuItem item)
{
mainWifi.StartScan();
char[] mine = "Starting Scan...".ToCharArray();
int length = mine.Length;
mainText.SetText(mine, 0, length);
return base.OnContextItemSelected(item);
}
protected override void OnPause()
{
RegisterReceiver(receiverWifi, new IntentFilter(WifiManager.ScanResultsAvailableAction));
base.OnPause();
}
protected override void OnResume()
{
RegisterReceiver(receiverWifi, new IntentFilter(WifiManager.ScanResultsAvailableAction));
base.OnResume();
}
// Broadcast receiver class called its receive method
// when number of wifi connections changed
private class WifiReceiver : BroadcastReceiver
{
// This method call when number of wifi connections changed
public override void OnReceive(Context context, Intent intent)
{
if (intent.Action.CompareTo(WifiManager.ScanResultsAvailableAction) == 0)
{
var sb = new StringBuilder();
wifiList = (List<ScanResult>)mainWifi.ScanResults;
sb.Append("\n Number Of Wifi connections :" + wifiList.Count + "\n\n");
for (int i = 0; i < wifiList.Count; i++)
{
sb.Append(new Integer(i + 1).ToString() + ". ");
sb.Append(wifiList[i].ToString());
sb.Append("\n\n");
}
char[] sb_t = (sb.ToString()).ToCharArray();
mainText.SetText(sb_t,0,sb_t.Length);
}
}
}
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);
}
}
}
Solution
About getting Wifi list in Xamarin.forms, I do one sample using DependencyService.
Creating interface in PCL:
public interface IWifi
{
Task<IEnumerable<string>> GetAvailableNetworksAsync();
}
Implementing the interface on Android platform
[assembly: Xamarin.Forms.Dependency(typeof(ListWifi.Droid.Wifi))]
namespace ListWifi.Droid
{
[Activity(Label = "ListWifi", 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 : IWifi
{
private Context context = null;
public Wifi()
{
this.context = Android.App.Application.Context;
}
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 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);
}
public IEnumerable<string> Scan()
{
tmr = new 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();
}
}
}
}
MainPage.xaml:
<StackLayout>
<ListView x:Name="wifilist">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout>
<Label Text="{Binding .}" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<Button
x:Name="btn1"
Clicked="btn1_Clicked"
Text="get wifi list" />
</StackLayout>
Mainpage.cs:
private async void btn1_Clicked(object sender, EventArgs e)
{
_wifiService = await DependencyService.Get<IWifi>().GetAvailableNetworksAsync();
wifilist.ItemsSource = _wifiService;
}
If you want to refresh wifi list in some time, you can use Timer to do this:
private async void btn1_Clicked(object sender, EventArgs e)
{
//_wifiService = await DependencyService.Get<IWifi>().GetAvailableNetworksAsync();
//wifilist.ItemsSource = _wifiService;
Device.StartTimer(new TimeSpan(0, 0, 60), () =>
{
// do something every 60 seconds
Device.BeginInvokeOnMainThread(async() =>
{
_wifiService = null;
_wifiService = await DependencyService.Get<IWifi>().GetAvailableNetworksAsync();
wifilist.ItemsSource = _wifiService;
});
return true; // runs again, or false to stop
});
}
Note: for WiFi Scanning, please permission.
