String address = "mynoipdomain"; //global variable
String lan = "myesplocalip"; // global variable

String serverAdress;
ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
    assert connectivityManager != null; //i added this line because Android Studio was giving warning that "Method invocation 'getNetworkInfo' may produce 'java.lang.NullPointerException'"
    if(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED ||
            connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED) {
        serverAdress = address + ":3001"; //3001 is port
    }
    else{
        serverAdress = lan + ":3001";
    }