java - 如何在 JPanel 上绘制图像

Question

我有一个战舰游戏，我试图在 Grid 对象上绘制船只、命中和未命中。 Grid 是具有许多Blocks 的 JPanel 实例。 Blocks 也是 JPanel，但是是 Grid 的属性。船只被绘制在网格上但位于 block 下方。是否可以在 block 上绘制？我尝试了玻璃板，但效果不太好。还有其他解决方案吗？

Answer 1

Is it possible to draw over the Blocks? I tried the Glass Pane and it didn't work too well. Any other solutions?

是的，一种不推荐但有时有用的方法是使用扩展的 JPanel 并覆盖 paint(Graphics g) 函数:

Class MyGridPane extends JPanel
{

 @Override
    public void paint(Graphics g) {
         super.paint(g); // <----- don't forget to call this

       // then anything you draw will appear above the child component's 
        Graphics2D g2d = (Graphics2D)g.create(); // cloning to work, it is safer aproach
        g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.3f));
        g2d.fillRect(0, 0, getWidth(), getHeight());
        g2d.dispose();// disposing the graphics object 
    }

}

或者，您可以考虑使用 JLayeredPane 来处理包含在目标面板(网格)层上方绘制的图像的面板。查看How to Use Layered Pane