ask user to turn on gps settings

Question

I would like to check if the user has GPS turned on, and if the user does not have gps turned on I would like to offer the user to turn it on.

I am following the guide on developer.android and since they are using updated API I find it hard to find good examples online.

this is my code

 LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder();

    //...
    SettingsClient client = LocationServices.getSettingsClient(this);
    Task<LocationSettingsResponse> task = client.checkLocationSettings(builder.build());


    task.addOnSuccessListener(this, new OnSuccessListener<LocationSettingsResponse>() {
        @Override
        public void onSuccess(LocationSettingsResponse locationSettingsResponse) {
            // All location settings are satisfied. The client can initialize
            // location requests here.
            // ...

            createLocationRequest();
        }
    });

    task.addOnFailureListener(this, new OnFailureListener() {
        @Override
        public void onFailure(@NonNull Exception e) {
            if (e instanceof ResolvableApiException) {


                try {
                    // Show the dialog by calling startResolutionForResult(),
                    // and check the result in onActivityResult().
                    ResolvableApiException resolvable = (ResolvableApiException) e;
                    resolvable.startResolutionForResult(MainActivity.this,
                            REQUEST_CHECK_SETTINGS);

                } catch (IntentSender.SendIntentException sendEx){
                    // Ignore the error.
                }
            }
        }
    });

It runs fine, but I dont get a dialog at all. Nothing is happening in my app, nor in logcat...