java为什么我的两个JButton设置为1时会占用2个空格（gridwidth）？

Question

我目前正在使用JavaSwing和GridBagLayout来尝试组织一些按钮。我遇到了一个问题，我的“cookieClick”和“shopButton”按钮占用了两个空间（gridx 0和1），首先，我将它们的网格x设置为1，并将权重x设置为1.0。任何帮助都会很好，谢谢

摇摆设置类

package com.jetbrains;
import javax.swing.*;
import java.awt.*;

public class GUI {
    final int screenX = 1280, screenY = 720;

    JFrame mainGui = new JFrame();

    JPanel gamePanel = new JPanel();
    JPanel shopPanel = new JPanel();

    JButton userName = new JButton("a"); // this is the area for the user's username they input in
    JButton cookieCounter = new JButton("b"); // this is the counter for how many cookies the user currently has
    JButton cookieClick = new JButton("c"); // this is the label for the cookie we click on
    JButton shopButton = new JButton("d"); // this takes us to the shop, probably some if statement and set visible etc.

    GridBagConstraints gameLayout = new GridBagConstraints();

    public void guiConfig() {
        mainGui.setSize(screenX, screenY);
        mainGui.setTitle("journey");
        mainGui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        mainGui.setResizable(false);
        mainGui.setBackground(Color.WHITE);
        mainGui.add(gamePanel);

        gamePanel.setSize(screenX, screenY);
        gamePanel.setLayout(new GridBagLayout());
    }

    public void labelPositioning() {
        gameLayout.fill = GridBagConstraints.HORIZONTAL;
        gameLayout.gridx = 0;
        gameLayout.gridwidth = 2;
        gameLayout.gridy = 0;
        gameLayout.weightx = 2.0;
        gameLayout.weighty = 1.0;
        gamePanel.add(cookieCounter, gameLayout);


        gameLayout.fill = GridBagConstraints.HORIZONTAL;
        gameLayout.gridx = 2;
        gameLayout.gridwidth = 1;
        gameLayout.gridy = 0;
        gameLayout.weightx = 1.0;
        gameLayout.weighty = 1.0;
        gamePanel.add(userName, gameLayout);


        gameLayout.fill = GridBagConstraints.HORIZONTAL;
        gameLayout.gridx = 1;
        gameLayout.gridwidth = 1;
        gameLayout.gridy = 1;
        gameLayout.weightx = 1.0;
        gameLayout.weighty = 1.0;
        gamePanel.add(cookieClick, gameLayout);


        gameLayout.fill = GridBagConstraints.HORIZONTAL;
        gameLayout.gridx = 1;
        gameLayout.gridwidth = 1;
        gameLayout.gridy = 2;
        gameLayout.weightx = 1.0;
        gameLayout.weighty = 1.0;
        gamePanel.add(shopButton, gameLayout);
    }

    public void frameVisibility() {
        mainGui.setVisible(true);
    }
}

主课

package com.jetbrains;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        GUI run = new GUI();
        run.guiConfig();
        run.labelPositioning();
        run.frameVisibility();
    }
}

Answer 1

GridBagLayout非常复杂，有时可以做你意想不到的事情。在本例中，GridBagLayout正在折叠第一列，因为其中（技术上）没有任何内容，这使它“看起来”就像其他按钮也在两列之间填充，而它们不是

例如。我在第一列（下一行）中添加了一个空的JLabel，并能够生成以下输出

import java.awt.Color;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                GUI gui = new GUI();
                gui.guiConfig();
                gui.labelPositioning();
                gui.frameVisibility();
            }
        });
    }

    public class GUI {

        final int screenX = 1280, screenY = 720;

        JFrame mainGui = new JFrame();

        JPanel gamePanel = new JPanel();
        JPanel shopPanel = new JPanel();

        JButton userName = new JButton("userName"); // this is the area for the user's username they input in
        JButton cookieCounter = new JButton("cookieCounter"); // this is the counter for how many cookies the user currently has
        JButton cookieClick = new JButton("cookieClick"); // this is the label for the cookie we click on
        JButton shopButton = new JButton("shopButton"); // this takes us to the shop, probably some if statement and set visible etc.

        GridBagConstraints gameLayout = new GridBagConstraints();

        public void guiConfig() {
            mainGui.setSize(screenX, screenY);
            mainGui.setTitle("journey");
            mainGui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//            mainGui.setResizable(false);
            mainGui.setBackground(Color.WHITE);
            mainGui.add(gamePanel);

//            gamePanel.setSize(screenX, screenY);
            gamePanel.setLayout(new GridBagLayout());
        }

        public void labelPositioning() {
            gameLayout.fill = GridBagConstraints.HORIZONTAL;
            gameLayout.gridx = 0;
            gameLayout.gridwidth = 2;
            gameLayout.gridy = 0;
            gameLayout.weightx = 2.0;
            gameLayout.weighty = 1.0;
            gamePanel.add(cookieCounter, gameLayout);

            gameLayout.fill = GridBagConstraints.HORIZONTAL;
            gameLayout.gridx = 0;
            gameLayout.gridwidth = 1;
            gameLayout.gridy = 0;
            gameLayout.weightx = 1.0;
            gameLayout.weighty = 1.0;
            gamePanel.add(new JLabel(), gameLayout);

            gameLayout.fill = GridBagConstraints.HORIZONTAL;
            gameLayout.gridx = 2;
            gameLayout.gridwidth = 1;
            gameLayout.gridy = 0;
            gameLayout.weightx = 1.0;
            gameLayout.weighty = 1.0;
            gamePanel.add(userName, gameLayout);

            gameLayout.fill = GridBagConstraints.HORIZONTAL;
            gameLayout.gridx = 1;
            gameLayout.gridwidth = 1;
            gameLayout.gridy = 1;
            gameLayout.weightx = 1.0;
            gameLayout.weighty = 1.0;
            gamePanel.add(cookieClick, gameLayout);

            gameLayout.fill = GridBagConstraints.HORIZONTAL;
            gameLayout.gridx = 1;
            gameLayout.gridwidth = 1;
            gameLayout.gridy = 2;
            gameLayout.weightx = 1.0;
            gameLayout.weighty = 1.0;
            gamePanel.add(shopButton, gameLayout);
        }

        public void frameVisibility() {
            mainGui.setVisible(true);
        }
    }
}

您需要记住，布局管理器使用组件的首选/min/max大小来确定单元的宽度和高度（以及其他约束），这将影响某些行/列的大小