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

public class LeftRightButton2 extends JPanel {
	private int x = 20;
	
	public LeftRightButton2() {
		setPreferredSize(new Dimension(200, 70));
		JButton lBtn = new JButton("Left");
		JButton rBtn = new JButton("Right");
		lBtn.addActionListener(new LeftListener());
		rBtn.addActionListener(new RightListener());
		setLayout(new FlowLayout());
		add(lBtn); add(rBtn);
	}

	private class LeftListener implements ActionListener {
		public void actionPerformed(ActionEvent e) {
			x -= 10;
			repaint();
		}
	}

	private class RightListener implements ActionListener {
		public void actionPerformed(ActionEvent e) {
			x += 10;
			repaint();
		}
	}

	@Override
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		g.drawString("HELLO WORLD!", x, 55);
	}

	public static void main(String[] args) {
		SwingUtilities.invokeLater(() -> {
			JFrame frame = new JFrame("ボタン");
			frame.add(new LeftRightButton2());
			frame.pack();
			frame.setVisible(true);;
			frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		});
	}
}