How to detect WiFi tethering state

Question

I want to know how to detect state of WiFi tethering. I\'ve seen an article: Android 2.3 wifi hotspot API But it doesn\'t work! It returns always WIFI_AP_STATE_DISABLED = 1.

Answer 1

In addition to the reflexion, to get the Wifi tethering status update, you can listen to this broadcast Action :

IntentFilter filter = new IntentFilter("android.net.wifi.WIFI_AP_STATE_CHANGED");

To get all tethering option update :

IntentFilter filter = new IntentFilter("android.net.conn.TETHER_STATE_CHANGED");

Those actions are hidden inside the Android source code

Answer 2

Using reflection:

WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
Method[] wmMethods = wifi.getClass().getDeclaredMethods();
for (Method method: wmMethods) {
  if (method.getName().equals("isWifiApEnabled")) {

    try {
      boolean isWifiAPenabled = method.invoke(wifi);
    } catch (IllegalArgumentException e) {
      e.printStackTrace();
    } catch (IllegalAccessException e) {
      e.printStackTrace();
    } catch (InvocationTargetException e) {
      e.printStackTrace();
  }
}

As you can see here

Answer 3

Reflection is a poor way to achieve this.

We can inspect the DhcpInfo to determine if the device is allocating addresses (mobile hotspot) or is being allocated by another DHCP server.

Here is a kotlin function that will determine if a device is a mobile hotspot, it has not been widely tested so YMMV.

fun isMobileHotspot(manager: WifiManager): Boolean {
  val info = manager.dhcpInfo
  return (
      info.ipAddress == 0
          && info.netmask == 0
          && info.gateway == 0
          && info.serverAddress == 16885952) // 192.168.1.1
}

Answer 4

Here is the Xamarin C# version if anyone is looking:

    static Method isWifiApEnabledMethod;

    public static bool IsWifiApEnabled ()
    {
        var wifiManager = WifiManager.FromContext (Application.Context);
        if (isWifiApEnabledMethod == null)
        {
            try
            {
                isWifiApEnabledMethod = wifiManager.Class.GetDeclaredMethod ("isWifiApEnabled");
                isWifiApEnabledMethod.Accessible = true; //in the case of visibility change in future APIs
            }
            catch (NoSuchMethodException e)
            {
                Debug.WriteLine ("Can't get method by reflection" + e);
            }
            catch (System.Exception ex)
            {
                Debug.WriteLine ("Can't get method by reflection" + ex);

            }
        }

        if (isWifiApEnabledMethod != null)
        {
            try
            {
                return (bool)isWifiApEnabledMethod.Invoke (wifiManager);
            }
            catch (System.Exception ex)
            {
                Debug.WriteLine ("Can't invoke by reflection" + ex);

            }
        }

        return false;
    }

Answer 5

First, you need to get WifiManager:

Context context = ...
final WifiManager wifi = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);

Then:

public static boolean isSharingWiFi(final WifiManager manager)
{
    try
    {
        final Method method = manager.getClass().getDeclaredMethod("isWifiApEnabled");
        method.setAccessible(true); //in the case of visibility change in future APIs
        return (Boolean) method.invoke(manager);
    }
    catch (final Throwable ignored)
    {
    }

    return false;
}

Also you need to request a permission in AndroidManifest.xml:

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>