java JButton在调整大小时以一种奇怪的方式复制自己

Question

所以，我正在为一个班级做一个多人乒乓球游戏，当我试着做一个按钮，然后调整窗口大小时，我遇到了这个奇怪的问题

缩短代码：

private void init(String title) {
    JFrame frame = new JFrame(title);
    frame.setMinimumSize(new Dimension(480, 480));
    frame.setSize(600, 600);
    frame.add(this);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
    frame.setFocusable(true);
    this.setFocusable(true);
    this.setBackground(Color.WHITE);
    Timer timer = new Timer(36, new TimeAction());
    timer.start();
    frame.addKeyListener(this);
}

public void addRestartButton() {
    JButton btnRestartGame = new JButton("Restart Game");

    btnRestartGame.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            pong.initServer();
            pong.nowReady();
            w.setVisible(false);
        }
    });
    btnRestartGame.setBounds(getWidth() / 2 - 100, getHeight() * 3 / 4, 200, 25);
    add(btnRestartGame);
}
public void paintComponent(java.awt.Graphics g) {
    super.paintComponent(g);
    Image bufferImage = createImage(this.getSize().width, this.getSize().height);
    Graphics2D bufferGraphics = (Graphics2D) bufferImage.getGraphics();

    bufferGraphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g2 = (Graphics2D) bufferGraphics;
    paintPolygon();
    paintBall();
    for (int i = 0; i < Pong.getPolygon().npoints; i++)
        paintSide(Pong.getPolygon().getSide(i));
    g2.setTransform(unrotate);
    paintScoreField();
    if (!pong.getScore().isPlaying()) {
        paintWinnerName(pong.getScore().getWinner());
        if (comm instanceof Server)
            addRestartButton();
    }

    g.drawImage(bufferImage, 0, 0, this);
}

有关问题的图片： http://imgur.com/a/rHxOa

有人知道为什么会发生这种情况，以及我如何解决它吗

Answer 1

在paintComponent方法中，删除这两行

// if (comm instanceof Server)
//   addRestartButton();