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

public class Graph2 extends JPanel implements ActionListener {
	private int[] is = {};
	private JTextField input;
	private final Color[] cs = {Color.RED, Color.BLUE};
	private final int scale = 15;
	
	public Graph2() {
		setPreferredSize(new Dimension(200, 200));
		input = new JTextField("", 16);
		input.addActionListener(this);
		setLayout(new FlowLayout());
		add(input);
	} 

	@Override
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		int i;
		int n = is.length;

		for (i = 0; i < n; i++) {
			g.setColor(cs[i % 2]);
			g.fillRect(0, i * scale + 30, is[i] * scale, scale);
		}
	}

	public void actionPerformed(ActionEvent e) {
		String[] args = input.getText().split(" ");
		int n = args.length;
		is = new int[n];

		int i;
		for(i = 0; i < n; i++) {
			is[i] = Integer.parseInt(args[i]);
		}
		repaint();
	}

	public static void main(String[] args) {
		SwingUtilities.invokeLater(() -> {
			JFrame frame = new JFrame("グラフ");
			frame.add(new Graph2());
			frame.pack();
			frame.setVisible(true);
			frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		});
	}
}