泡泡射击，绘制气泡

Question

我尝试制作一个泡泡射击游戏，我在MyPanel上绘制气泡的问题延伸了JPanel。类泡（扩展JButton）有方法paintComponent：

public void paintComponent(Graphics g){
    Graphics2D g2d = (Graphics2D) g;
    RenderingHints qualityHints = new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    qualityHints.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
    g2d.setRenderingHints(qualityHints);
    g2d.setColor(c);
    g2d.fillOval(this.x,this.y,this.r, this.r);
}

我应该如何制作MyPanel的构造函数和方法paint（）;在MyPanel类中，如果我想在20列，10行中显示Bubbles？