MathApp, SettingsActivity.java

package com.example.mathapplication;

import android.os.Bundle;
import android.view.View;
import android.widget.CheckBox;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

public class SettingsActivity extends AppCompatActivity {
    SeekBar skbMin, skbMax;
    TextView tvMin, tvMax;
    CheckBox chkAdd, chkSub, chkMul, chkDiv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_settings);

        skbMin = findViewById(R.id.skbMin);
        skbMax = findViewById(R.id.skbMax);
        tvMin = findViewById(R.id.tvMin);
        tvMax = findViewById(R.id.tvMax);
        chkAdd = findViewById(R.id.chkAdd);
        chkSub = findViewById(R.id.chkSub);
        chkMul = findViewById(R.id.chkMul);
        chkDiv = findViewById(R.id.chkDiv);

        skbMin.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                tvMin.setText("min = " + progress);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });

        skbMax.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                tvMax.setText("max = " + progress);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });
        skbMin.setProgress(Settings.min);
        skbMax.setProgress(Settings.max);

        chkAdd.setChecked(Settings.add);
        chkSub.setChecked(Settings.sub);
        chkMul.setChecked(Settings.mul);
        chkDiv.setChecked(Settings.div);
    }

    public void saveSettingsCLicked(View view) {
        Settings.min = skbMin.getProgress();
        Settings.max = skbMax.getProgress();
        Settings.add = chkAdd.isChecked();
        Settings.sub = chkSub.isChecked();
        Settings.mul = chkMul.isChecked();
        Settings.div = chkDiv.isChecked();

        Settings.saveSettings(this);
        Toast.makeText(this, "Settings saved successfully !!!", Toast.LENGTH_LONG).show();
        finish();
    }

    public void cancelClicked(View view) {
        finish();
    }
}