package ex4;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
import javax.swing.WindowConstants;

public class Counter extends JPanel {
	int value = 0;

	public Counter() {
		super(new BorderLayout());
		JFrame frame = new JFrame("Counter");
		frame.setContentPane(this); // adds the panel
		final JLabel display = new JLabel("0");
		display.setHorizontalAlignment(SwingConstants.CENTER);
		add(display, BorderLayout.CENTER);
		
		JButton increment = new JButton("Increment");
		add(increment, BorderLayout.SOUTH);
		increment.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				value++;
				display.setText(Integer.toString(value));
				repaint();
			}
		});
		
		frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
		frame.pack();
		frame.setVisible(true);
	}

	public static void main(String[] args) {
		javax.swing.SwingUtilities.invokeLater(new Runnable() {
			public void run() {
				new Counter();
			}
		});
	}

}