在 JButton 上绘制图形

发布于 2024-08-24 13:49:14 字数 699 浏览 2 评论 0原文

我遇到的情况是，GridLayout 上有一堆 JButton。我需要每个 JButton 都具有：

背景图像（但保留在需要时保持默认按钮外观的能力）
由其他类在顶部绘制的自定义图形

我对背景图像没有任何问题，因为我使用的是 setIcon()但我在背景上绘制东西时遇到问题。有一次我可以在按钮顶部绘图，但是单击按钮后，绘图就消失了。如何让按钮保持这种绘图状态？

基本上，我需要一种方法让我的 JButton 具有公共方法，允许另一个类在其上绘制任何内容，例如：

public void drawSomething() {
  Graphics g = this.getGraphics();
  g.drawOval(3,2,2,2);
  repaint();
}

或者

public Graphics getGraphics() {
  return this.getGraphics();
}

另一个类可以执行此操作：

button.getGraphics().drawSomething();

后者更符合我的要求，但第一个同样有用。

有什么办法可以解决这个问题吗？另外，重写父类方法 PaintComponent() 没有帮助，因为我需要每个按钮都有不同的图形。

原文

I have a situation wherein I have a bunch of JButtons on a GridLayout. I need each of the JButtons to have:

a background image (but retain the ability to keep the default button look if needed)
custom graphics drawn on top by other classes

I have no trouble with the background image, since I am using setIcon() but I am having problems drawing things on top of the background. At one point I was able to draw on top of the button, but after the button was clicked, the drawings disappeared. How can make the button keep this drawing state?

Basically, I need a way for my JButtons to have public methods that would allow another class to draw anything on it such as:

public void drawSomething() {
  Graphics g = this.getGraphics();
  g.drawOval(3,2,2,2);
  repaint();
}

public Graphics getGraphics() {
  return this.getGraphics();
}

then another class could do this:

button.getGraphics().drawSomething();

The latter is more what I am looking for but the first is equally useful.

Is there any way to go about this? Also, overriding the parent class method paintComponent() doesn't help since I need each button to have different graphics.

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把梦留给海 2024-08-31 13:49:14

您可以子类化 JButton 并重写 PaintComponent()。
您可以通过为子类提供外部“画家”来处理具有不同图形的每个按钮。或者只是为每个不同的图形设置不同的子类。

public class MyButton extends JButton {
    private Painter painter;

    public void paintComponent(Graphics g) {
       super.paintComponent(g);
       painter.paint(g);
    }
}

public interface Painter {
    public void paint(Graphics g);
}

您不能像现在一样只在按钮上绘画，因为下次重新绘制按钮时绘画会丢失。

you can subclass JButton and override paintComponent().
you can handle each button having a different graphic by providing an external 'painter' to the subclass. Or just have a different subclass for each different graphic.

public class MyButton extends JButton {
    private Painter painter;

    public void paintComponent(Graphics g) {
       super.paintComponent(g);
       painter.paint(g);
    }
}

public interface Painter {
    public void paint(Graphics g);
}

you cannot just paint on the button as you are doing as the painting will get lost when the button is next repainted.

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