https://hashcode.co.kr/questions/12619/sharedpreferences%EB%A1%9C-textview-%EC%A0%80%EC%9E%A5%ED%95%98%EB%8A%94%EB%B2%95

ClickerFragment.java

public class ClickerFragment extends Fragment {
    public static final String TAG = ClickerFragment.class.getSimpleName();

    private SharedPreferences prefs;
    private int counter;
    
    private TextView counterText;
    private Button up;
    private Button reset;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        prefs = getActivity().getSharedPreferences("counter_alone", Context.MODE_PRIVATE);
        counter = prefs.getInt("counter", 0);
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @NonNull ViewGroup container, @NonNull Bundle savedInstanceState) {
        View v= inflater. inflate(R.layout.counter_alone, container, false);

        counterText = v.findViewById(R.id.counterText);
        up = v.findViewById(R.id.up);
        reset = v.findViewById(R.id.reset);
        
        up.setOnClickListener(onClickListener);
        reset.setOnClickListener(onClickListener);

        counterText.setText(counter + "");
        return v;
    }
    
    
    private View.OnClickListener onClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            switch (v.getId()) {
                case R.id.up:
                    counter++;
                    prefs.edit().putInt("counter", counter).apply();
                    counterText.setText(counter + "");
                    break;
                case R.id.reset:
                    counter = 0;
                    prefs.edit().remove("counter").apply();
                    counterText.setText(counter + "");
                    break;
            }
        }
    };

}