View.java

package view;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;

public class View {
    //vars
    private int width;
    private int height;
    private ActionListener listener;

    //methods
    private void initGUI() {
        JFrame frame = new JFrame("Shapes");
        JPanel panel = new JPanel();

        JButton btnSmall = new JButton("Small");
        JButton btnMed = new JButton("Medium");
        JButton btnLarge = new JButton("Large");

        //set ActionListener on each button (see method below=
        handleEvents(btnSmall, btnMed, btnLarge);

        panel.setLayout(new GridLayout(1, 5, 3, 3));
        panel.add(btnSmall);
        panel.add(btnMed);
        panel.add(btnLarge);

        frame.add(panel);
        frame.setResizable(false);
        frame.pack();
        frame.getContentPane().setLayout(new FlowLayout());
        frame.setSize(new Dimension(width, height));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    //set the same listener for each given button
    private void handleEvents(JButton... btn) {
        for (JButton button : btn) {
            if (null != button) {
                button.addActionListener(this.listener);
            }
        }
    }

    //construtor
    public View(int width, int height, ActionListener e) {
        this.width = width;
        this.height = height;
        this.listener = e;
        initGUI();
    }
}