BorderLayout无法正确显示 [英] BorderLayout doesn't show correctly

问题描述

我想要一个JFrame，左边和右边有一个边框，颜色为黑色，宽度为withfOfJFrame / 10。

I want to have a JFrame, where on the left and the right there is a border that has the color black and a width of withfOfJFrame/10.

现在，我的尝试看起来像这样：

Now, my try at it looks like this:

JFrame f = new JFrame();
f.setSize(800, 600);
f.setLayout(new BorderLayout());

JPanel leftBorder = new JPanel();
JPanel rightBorder = new JPanel();
leftBorder.setBackground(Color.black);
rightBorder.setBackground(Color.black);
leftBorder.setSize(f.getWidth()/10, f.getHeight());
rightBorder.setSize(f.getWidth()/10, f.getHeight());
JPanel center = new JPanel();
center.setBackground(Color.red);

f.add(leftBorder, BorderLayout.WEST);
f.add(center, BorderLayout.CENTER);
f.add(rightBorder, BorderLayout.EAST);    
f.setVisible(true);

这会在左侧和右侧添加黑色边框，但该边框具有固定大小并且不会调整窗口大小时重新计算。大小甚至不是800的1/10（JFrame的起始宽度）。

This adds a black border on the left and the right, but that border has a fixed size and doesn't recalculate when resizing the window. The size isn't even 1/10 of 800 (the beginning width of the JFrame).

我做错了什么？或者还有更好的方法吗？

What am I doing wrong? Or is there even a better way to do this?

推荐答案

您可以使用 GridBagLayout 和适当的权重：

You may achieve the desired result with a GridBagLayout and appropriate weights:

public class Snippet {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                JFrame f = new JFrame();
                f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

                JPanel leftBorder = new JPanel();
                JPanel rightBorder = new JPanel();
                leftBorder.setBackground(Color.black);
                rightBorder.setBackground(Color.black);

                JPanel center = new JPanel();
                center.setBackground(Color.red);

                f.setLayout(new GridBagLayout());

                GridBagConstraints gbc = new GridBagConstraints();
                gbc.fill = GridBagConstraints.BOTH;
                gbc.weighty = 1.0;
                gbc.gridy = 0;
                gbc.gridwidth = 1;
                gbc.gridheight = 1;

                gbc.gridx = 0;
                gbc.weightx = 0.1;
                f.add(leftBorder, gbc);

                gbc.gridx = 1;
                gbc.weightx = 0.8;
                f.add(center, gbc);

                gbc.gridx = 2;
                gbc.weightx = 0.1;
                f.add(rightBorder, gbc);

                f.pack();
                f.setVisible(true);
            }
        });
    }
}

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