WiFiConnect.kt

private fun connectToWifi(ssid:String, password:String) {

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
    
        val wifiNetworkSpecifier = WifiNetworkSpecifier.Builder()
            .setSsid(ssid)
            .setWpa2Passphrase(password)
            .build()

        val networkRequest = NetworkRequest.Builder()
            .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
            .setNetworkSpecifier(wifiNetworkSpecifier)
            .build()

        val connectivityManager =
            applicationContext!!.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
        connectivityManager.requestNetwork(networkRequest, ConnectivityManager.NetworkCallback())
        
        // TODO: check connection
        return "connected ?"
    
    } else {
    
        WifiConfiguration wifiConfig = new WifiConfiguration();
        wifiConfig.SSID = String.format("\"%s\"", ssid);
        wifiConfig.preSharedKey = String.format("\"%s\"", password);
        WifiManager wifiManager = (WifiManager)getSystemService(WIFI_SERVICE);
        //remember id
        int netId = wifiManager.addNetwork(wifiConfig);
        wifiManager.disconnect();
        wifiManager.enableNetwork(netId, true);

        boolean isConnectionSuccessful = wifiManager.reconnect();

        if(isConnectionSuccessful) {
            return "connection successful";
        } else {
            return "invalid credential";
        }
    }
}