Android - Guardar objeto con Shared preferences

package de.miguel.frozzenlist.frozzenbetaa;

import androidx.appcompat.app.AppCompatActivity;

import android.content.SharedPreferences;

import android.os.Bundle;

import android.view.View;

import android.widget.EditText;

public class Register extends AppCompatActivity {

    SharedPreferences mySPR;

    private SharedPreferences.Editor preferenceEditor;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_register);

    }

    public void Register(View view) {

        //decliation

        String input;

        String inputE;

        String inputP;

        String inputControlP;

        Counter counter = null;

        SharedPreferences mySPR;

        int inputID;

        User user =new User();

        String userData;

        //source

        EditText inputName= (EditText)findViewById(R.id.bntInputName);

        EditText inputEmail=(EditText)findViewById(R.id.bntInputEmail);

        EditText setContrasena=(EditText)findViewById(R.id.bntsetContrasena);

        EditText setControlContrasena=(EditText)findViewById(R.id.bntControlContrasena);

        //set to User

        input= (inputName.getText().toString());

        inputE= (inputEmail.getText().toString());

        inputP= (setContrasena.getText().toString());

        inputControlP=(setControlContrasena.getText().toString());

       user.setUserName(input);

       user.setEmail(inputE);

        if(input.equals(inputControlP)){

            user.setContrasena(inputP);

        }

        inputID=counter.getId();

        user.setUserID(inputID);

        userData= user.toString();

       mySPR= getSharedPreferences("database",0);

        SharedPreferences.Editor editor=mySPR.edit();

    }

  }