java - GridBagLayout 从屏幕中间启动 Jbuttons

Question

我在 GridBagLayout 中有 14 个按钮。问题是按钮从屏幕中间垂直开始，而不是从开始屏幕开始。另外我想要的是按钮大小相同，并在按钮之间添加一些空间。

这是我的代码:

    private final int MAX_TABLES = 14;
    JButton [] buttonsTables = new JButton[MAX_TABLES];

    frame = new JFrame("FreshPos baza podataka");
    frame.setExtendedState(JFrame.MAXIMIZED_BOTH);

    //Main panel
    JPanel panel = new JPanel();        
    panel.setLayout(new BorderLayout());
    frame.getContentPane().add(panel);

    //West panel;
    JPanel panelWest = new JPanel(new GridBagLayout());     
    panel.add(panelWest, BorderLayout.WEST);

    GridBagConstraints c = new GridBagConstraints();
    c.gridx = 0;
    c.gridy = 0;
    c.anchor = GridBagConstraints.CENTER;

    for (int i = 0; i < MAX_TABLES; i++) {          
        buttonsTables[i] = new JButton(tables[i]);
        buttonsTables[i].setMaximumSize(new Dimension(Integer.MAX_VALUE, buttonsTables[i].getMinimumSize().height));
        panelWest.add(buttonsTables[i], c);
        c.gridy++;
        panelWest.add(Box.createVerticalStrut(10));                     

    }

Answer 1

如果您希望按钮大小相同，请考虑使用 GridLayout，它带有一个在组件之间添加空间的构造函数:

new GridLayout(0, 1, 0, 5); // variable number of rows, 1 column, 5 pixels between

如果您绝对必须使用 GridBagLayout，请将约束的填充属性设置为 GridBagConstraints.HORIZONTAL 或 GridBagConstraints.BOTH，并将 anchor 属性设置为 GridBagConstraints。西

有关创建一堆 JButton 的示例，将它们放在屏幕左侧的网格中:

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import javax.swing.*;

@SuppressWarnings("serial")
public class ButtonsOnSide extends JPanel {
    private static final String[] BTN_TEXTS = { 
            "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday",
            "Sunday", "January", "February", "March", "April", "May", "June", 
            "July", "August", "September", "October","November", "December" };
    private static final int PREF_W = 1000;
    private static final int PREF_H = 800;
    private static final int GAP = 4;

    public ButtonsOnSide() {
        JPanel btnPanel = new JPanel(new GridLayout(0, 1, 0, GAP));
        for (String btnText : BTN_TEXTS) {
            JButton btn = new JButton(btnText);
            btn.addActionListener(e -> System.out.println(e.getActionCommand()));
            btnPanel.add(btn);
        }
        // wrapper panel to help center the button panel vertically
        JPanel wrapperPanel = new JPanel(new GridBagLayout());
        wrapperPanel.add(btnPanel);

        setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
        setLayout(new BorderLayout());
        add(wrapperPanel, BorderLayout.LINE_START); // add to the left side
    }

    @Override
    public Dimension getPreferredSize() {
        if (isPreferredSizeSet()) {
            return super.getPreferredSize();
        }
        return new Dimension(PREF_W, PREF_H);
    }

    private static void createAndShowGui() {
        JFrame frame = new JFrame("ButtonsOnSide");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new ButtonsOnSide());
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGui());
    }
}