如何在另一个JPanel内的JPanel上绘制形状? [英] How do you draw shapes on a JPanel, which is within another JPanel?

问题描述

我目前正在尝试在JFrame内另一个JPanel内的JPanel上绘制形状.

I'm currently trying to draw shapes on a JPanel, which is within another JPanel, within a JFrame.

我搜索了Google和Youtube，发现如何在具有一个面板的JFrame中绘制形状，但是没有发现任何可以帮助我完成工作的东西. (也许我没看到什么).

I've searched Google and Youtube and found out how to draw shapes within a JFrame that has one panel, but have found nothing which can help me with what I'm doing. (maybe I'm not seeing something).

到目前为止我看到的代码:

Code I've seen so far:

public class GameScreen 
{
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        g.setColor(Color.red);
        g.drawRect(100, 10, 30, 40);
    }

    public static void main(String[] args)
    {
       GameScreen gs = new GameScreen();
       JFrame f = new JFrame();
       f.setTitle("");
       f.setSize(400,400);
       f.setVisible(true);
       f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       f.add(gs);
}

当我只处理一个面板时，这一切都很好，但是我想在我创建的第一个面板内的面板上显示形状.

This is all good for when I'm dealing with just one panel, but I wanna display shapes on a panel which is within the 1'st panel I've created.

推荐答案

以与现在相同的方式将JPanel添加到JFrame，但是使用您自己的JPanel子类来完成.

Add a JPanel to the JFrame in the same way as you're doing now, but do it with your own subclass of JPanel.

class MyPanel extends JPanel {
    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.setColor(Color.red);
        g.drawRect(100, 10, 30, 40);
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(400,400); // As suggested by camickr
    }
}

您可以将其添加到位于JFrame内的JPanel中

You can add this to a JPanel which sits within the JFrame

public static void main(String[] args)
{
   MyPanel mp = new MyPanel();
   JPanel jp = new JPanel();
   jp.add(mp);

   JFrame f = new JFrame();
   f.setTitle("");
   f.setSize(400,400);
   f.setVisible(true);
   f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   f.add(jp);
}

如果您将它们添加为子组件，则该方法适用于组件中的组件.关键是扩展组件并覆盖您想要更改的方法.

This can work for components within components, if you add them as children components. The key is to extend the component and override the methods you wish to change.

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