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我正在尝试创建一个 Java Applet，我在 Java 网站上四处寻找，发现了一个我编辑的好例子。

在此示例中，有 3 个按钮，一个类似于页眉，一个类似于页脚，一个类似于正文。我的问题是，中间（主体）按钮不会完全展开。

如果你运行这段代码，你就会明白我的意思。

import java.awt.*;
import javax.swing.JButton;
import javax.swing.JFrame;

public class main {
    final static boolean shouldFill = true;
    final static boolean shouldWeightX = true;
    final static boolean RIGHT_TO_LEFT = false;

    public static void addComponentsToPane(Container pane) {
        if (RIGHT_TO_LEFT) {
            pane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
        }

        JButton button;
    pane.setLayout(new GridBagLayout());
    GridBagConstraints c = new GridBagConstraints();
    if (shouldFill) {
    //natural height, maximum width
    c.fill = GridBagConstraints.HORIZONTAL;
    }


    button = new JButton("hi");
    c.fill = GridBagConstraints.HORIZONTAL;
    c.weightx = 0.5;
    c.gridx = 1;
    c.gridy = 0;
    c.ipady = 40;
    pane.add(button, c);

    button = new JButton("Hello, i will not expand");
    c.fill = GridBagConstraints.BOTH;
    c.weighty = 1.0;   //request any extra vertical space
    c.weightx=1.0;
    c.anchor = GridBagConstraints.CENTER; //bottom of space
    c.insets = new Insets(10,0,0,0);  //top padding
    c.gridx = 1;       //aligned with button 2
    c.gridy = 1;       //third row
    pane.add(button, c);


    button = new JButton("fr");
    c.fill = GridBagConstraints.HORIZONTAL;
    c.ipady = 0;       //reset to default
    c.weighty = 1.0;   //request any extra vertical space
    c.anchor = GridBagConstraints.PAGE_END; //bottom of space
    c.insets = new Insets(10,0,0,0);  //top padding
    c.gridx = 1;       //aligned with button 2
    c.gridwidth = 2;   //2 columns wide
    c.gridy = 2;       //third row
    pane.add(button, c);
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("main");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Set up the content pane.
        addComponentsToPane(frame.getContentPane());

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

在此处输入图像描述

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2 回答 2

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看起来不是中间按钮的错，而是底部按钮没有展开，如果您将底部按钮设置为这样，c.fill = GridBagConstraints.BOTH;那么它会占用下面的空白空间。

你想让中间更大吗？您可能想将底部按钮的权重更改为 0.5 c.weighty = .5; //request any extra vertical space
，看看是否是您要找的？

如果您希望中间比顶部和底部大得多，您可能需要制作更多的网格空间，而不是 1,1,1，尝试 1,3,1 等

于 2012-04-04T21:27:10.013 回答
2

我在 Java 网站上环顾四周，发现了一个我编辑的很好的例子。

所以我认为你不必使用 GridBagLayout？

使用BorderLayout，在BorderLayout.CENTER 位置制作可展开按钮。

http://docs.oracle.com/javase/tutorial/uiswing/layout/border.html

于 2012-04-04T21:30:02.693 回答