android facebook login button behaviour

Question

I implemented Facebook Login functionality in my android app. But there is a unwanted behaviour that appears.

loginButton.registerCallback(callbackManager,
            object : FacebookCallback<LoginResult> {
                override fun onSuccess(result: LoginResult?) {
                    Log.d("mytag", "onSuccess: ${result?.accessToken?.userId}")
                }

                override fun onCancel() {

                }

                override fun onError(error: FacebookException?) {

                }

            })

So when onSuccess is called, everything is okay, i get the userId. But internally this saves some user authentication data inside SharedPreferences. Which is not what i want, my intention is to get only userId and send it to my server and that is it. (I mean it is not actually my aim to use facebook login for app, i just want to get userProfile image and send it to server).

How can i achieve this result?