MyCounterApplicatin, MainActivity.java

package com.example.mycounterapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;


public class MainActivity extends AppCompatActivity {
    // 1 - define variables
    private TextView tvMyCounter;
    private Button btnAdd, btnMinus, btnRestart, btnQuit;

    private int count = 0;

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

        // 2 - set layout connection to local variables
        tvMyCounter = findViewById(R.id.tvCounter);
        btnAdd = findViewById(R.id.btnAdd);
        btnMinus = findViewById(R.id.btnMinus);
        btnRestart = findViewById(R.id.btnRestart);
        btnQuit = findViewById(R.id.btnQuit);

        // 3 - test
        tvMyCounter.setText("0");
    }

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

    public void add(View view) {
        count++;
        tvMyCounter.setText(count + "");
    }

    public void minus(View view) {
        if (count > 0) {
            count--;
            tvMyCounter.setText(count + "");
        }
    }

    public void restart(View view) {
        count = 0;
        tvMyCounter.setText("0");
    }
}