在 JPanel 上绘制后如何重新绘制它? [英] How to repaint a JPanel after have drawn on it?

问题描述

我有一个继承自 JPanel 的组件，我在其上绘制了一个网格.现在我有一个 JComboBox，我希望用户能够在这里选择网格大小，然后按下一个按钮来改变网格(重新绘制网格).

I have a component that inherits from JPanel, I draw a grid on it. Now I have a JComboBox and I want the user to be able to choose the grid size here and then press a button to make the grid change (repaint the grid).

问题是它绘制了初始网格，但是一旦用户从 JComboBox 中选择了网格大小并单击了按钮，则什么也没有发生.我必须将表单最小化，然后再次恢复以查看更改.

The thing is that it paints the initial grid, but once the user choses a grid size from the JComboBox and clicks the button, nothing happens. I have to minimize the form and then restore it again to see the changes.

有什么想法吗?代码如下.

Any Ideas? The Code is below.

public class Board extends JPanel {
    ...

    protected void paintComponent(Graphics og) {
        super.paintComponent(og);
        ...
        }
    }    
}

主类

public class Main extends javax.swing.JFrame {
...

public Main() {                                   //This works great.
    board = new Board( ... );
    somePanel.add(board, BorderLayout.CENTER);

}

public void someButtonActionPerformed(Event e) { //This is not working

    somePanel.remove(board);
    board = new Board( ... );
    somePanel.add(board);
    somePanel.invalidate()
    board.repaint();
}

推荐答案

尝试调用 somePanel.revalidate().这将告诉 AWT 您已经更改了组件树.

Try calling somePanel.revalidate(). That will tell the AWT that you have changed the component tree.

从 invalidate 更改为 revalidate

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