Untitled

package com.example.myfirstapp;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private Button myButton;

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

        myButton = findViewById(R.id.button);

        myButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                showToast("Hello, Android!");
            }
        });
    }

    private void showToast(String message) {
        Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show();
    }
}