What is alternative to ConnectivityManager.TYPE_WIFI deprecated in Android P API 28?

You can use below snippet to check if you have Wifi connection or Cellular:

ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
    Network network = connectivityManager.getActiveNetwork();
    NetworkCapabilities capabilities = connectivityManager.getNetworkCapabilities(network);
    return capabilities != null && (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) || capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR));
}

ConnectivityManager.TYPE_WIFI is Deprecated. You should use NetworkCapabilities.

This replaces the old ConnectivityManager.TYPE_MOBILE method of network selection. Rather than indicate a need for Wi-Fi because an application needs high bandwidth and risk obsolescence when a new, fast network appears (like LTE), the application should specify it needs high bandwidth. Similarly if an application needs an unmetered network for a bulk transfer it can specify that rather than assuming all cellular based connections are metered and all Wi-Fi based connections are not.

Applications should instead use NetworkCapabilities.hasTransport(int) or requestNetwork(NetworkRequest, NetworkCallback) to request an appropriate network. for supported transports.

You can try this way

NetworkAgentInfo networkAgent;
int type = ConnectivityManager.TYPE_NONE;
if (networkAgent.networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) {
     type = ConnectivityManager.TYPE_MOBILE;
} else if (networkAgent.networkCapabilities.hasTransport(
     NetworkCapabilities.TRANSPORT_WIFI)) {
     type = ConnectivityManager.TYPE_WIFI;
}

Use below method.. 19/06/2019

public boolean isconnectedToWifi(Context context) {
    ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    if (connectivityManager == null) {
        return false;
    }

    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
        Network network = connectivityManager.getActiveNetwork();
        NetworkCapabilities capabilities = connectivityManager.getNetworkCapabilities(network);
        if (capabilities == null) {
            return false;
        }
        return capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI);
    } else {
        NetworkInfo networkInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
        if (networkInfo == null) {
            return false;
        }
        return networkInfo.isConnected();
    }
}