java - 是否可以构建相同的 GridBagLayout 界面但不使用额外的 JPanel 作为容器？

Question

我正在使用GridBagLayout来设计界面。接口(interface)有一个JTabbedPane设置为北并在我调整大小时填充两个方向，就在 JTabbedPane 的下方有两个JButton s。

我想要实现的是将这两个按钮放在东处，并仅使用GridBagLayout功能(没有引入额外的 JPanel )，但我没有这样做。

|-[选项卡]--------------------------|
|--------------------------------|
|--------------------------------|
|--------------------------------|
|--------------------------------|
|-------------[按钮][按钮]|

当我将两个按钮的布局约束设置为“西”(而不是“东”)时。两者都正确地向西!

c.anchor = GridBagConstraints.WEST;

但是当我将两个按钮的布局约束设置为东时

c.anchor = GridBagConstraints.EAST;

其中一个向东，另一个向西!

为了解决这个问题，我添加了 JPanel按住两个按钮并添加此 JPanel进入界面，并将其布局约束设置为 c.anchor = GridBagConstraints.EAST; 。效果很好。

但是是否可以构建相同的 GridBagLayout无需使用额外的接口(interface)JPanel作为容器？

以下两类采用SSCCE格式；第一个显示问题 GridBagTest ，另一个显示解决方案 GridBagTest_solved 利用额外的 JPanel

问题类别:

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

public class GridBagTest extends JPanel {

    JFrame frame;
    JTabbedPane tabbedPane;
    JPanel panel_tab;

    JButton btn_previous;
    JButton btn_next;

    private void create_and_layout() {

        this.setLayout(new GridBagLayout());

        tabbedPane = new JTabbedPane() {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(300, 150);
            }
        };

        panel_tab = new JPanel();
        tabbedPane.addTab("Tab 1", panel_tab);

        btn_previous = new JButton("previous");
        btn_next = new JButton("  next  ");

        GridBagConstraints c;

        c = new GridBagConstraints();
        c.gridx = 0;
        c.gridy = 0;
        c.weightx = 1;
        c.gridwidth = 2;
        c.weighty = 1;
        c.fill = GridBagConstraints.BOTH;
        c.anchor = GridBagConstraints.NORTH;
        this.add(tabbedPane, c);

        c = new GridBagConstraints();
        c.gridx = 0;
        c.gridy = 1;
        c.anchor = GridBagConstraints.EAST;
        c.insets = new Insets(2, 0, 2, 2);
        this.add(btn_previous, c);

        c = new GridBagConstraints();
        c.gridx = 1;
        c.gridy = 1;
        c.anchor = GridBagConstraints.EAST;
        c.insets = new Insets(2, 0, 2, 2);
        this.add(btn_next, c);
    }

    private void initGUI() {
        create_and_layout();
        frame = new JFrame("GridBagTest");
        frame.getContentPane().add(this);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        java.awt.EventQueue.invokeLater(new GridBagTest()::initGUI);
    }
}

解决方案类别:

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

public class GridBagTest_solved extends JPanel {

    JFrame frame;
    JTabbedPane tabbedPane;
    JPanel panel_tab;
    JPanel panel_buttons;

    JButton btn_previous;
    JButton btn_next;

    private void create_and_layout() {

        this.setLayout(new GridBagLayout());

        tabbedPane = new JTabbedPane() {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(300, 150);
            }
        };

        panel_tab = new JPanel();
        tabbedPane.addTab("Tab 1", panel_tab);

        panel_buttons = new JPanel(new GridBagLayout());

        btn_previous = new JButton("previous");
        btn_next = new JButton("  next  ");

        GridBagConstraints c;
        // Adding buttons to panel_buttons
        c = new GridBagConstraints();
        c.gridx = 0;
        c.gridy = 0;
        c.insets = new Insets(2, 0, 2, 2);
        panel_buttons.add(btn_previous, c);

        c = new GridBagConstraints();
        c.gridx = 1;
        c.gridy = 0;
        c.insets = new Insets(2, 0, 2, 2);
        panel_buttons.add(btn_next, c);

        // Adding tabbedPane & panel_buttons to this (GridBagTest_solved)
        c = new GridBagConstraints();
        c.gridx = 0;
        c.gridy = 0;
        c.weightx = 1;
        c.weighty = 1;
        c.fill = GridBagConstraints.BOTH;
        c.anchor = GridBagConstraints.NORTH;
        this.add(tabbedPane, c);

        c = new GridBagConstraints();
        c.gridx = 0;
        c.gridy = 1;
        c.anchor = GridBagConstraints.EAST;
        this.add(panel_buttons, c);
    }

    private void initGUI() {
        create_and_layout();
        frame = new JFrame("GridBagTest_solved");
        frame.getContentPane().add(this);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        java.awt.EventQueue.invokeLater(new GridBagTest_solved()::initGUI);
    }
}

Answer 1

如果您只有三个组件 - JTabbedPane 和两个 JButton，您应该考虑使用比 GridBag 更简单的布局。只需使用主面板的 BorderLayout，将 JTabbedPane 放置在 CENTER 中，将 JPanel 放置在 SOUTH 中，该 JPanel 具有 TRAILING 对齐的 FlowLayout，然后将两个按钮添加到该 JPanel 中。