如何在JPanel中将组件左对齐？

Question

我创建了一个基本文本编辑器的布局，我希望顶部栏上的按钮左对齐，顶部栏是一个JPanel，并且使用FlowLayout管理器。它在GridBag布局管理器中。有什么建议吗？

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

public class GridTest {
private static JButton firstButton, secondButton, thirdButton;
private static JPanel panel, sidebar, infoPanel;
private static JTextArea textArea;

public static void addComponentsToPane(Container container) {
    container.setLayout(new GridBagLayout());
    GridBagConstraints c = new GridBagConstraints();

    firstButton = new JButton("Button 1");
    secondButton = new JButton("Button 2");
    thirdButton = new JButton("Button 3");

    panel = new JPanel(new FlowLayout());
    sidebar = new JPanel(new FlowLayout());
    infoPanel = new JPanel(new FlowLayout());

    textArea = new JTextArea("This is some generic text!");

    c.fill = GridBagConstraints.HORIZONTAL;
    c.ipady = 0; 
    c.weighty = 0;
    c.weightx = 1;
    c.gridx = 0;
    c.gridwidth = 3;
    c.gridy = 0;
    c.anchor = GridBagConstraints.LINE_START; 
    container.add(panel, c);

    panel.setComponentOrientation(ComponentOrientation.LEFT_TO_RIGHT);
    panel.setBorder(BorderFactory.createLineBorder(Color.black));
    panel.add(firstButton);
    panel.add(secondButton);
    panel.add(thirdButton);

    c.fill = GridBagConstraints.BOTH;
    c.ipady = 300; 
    c.ipadx = 100;
    c.weighty = 1;
    c.weightx = 0;
    c.gridx = 0;
    c.gridheight = 2;
    c.gridwidth = 1;
    c.gridy = 1;
    container.add(sidebar, c);

    sidebar.setBorder(BorderFactory.createLineBorder(Color.black));

    c.fill = GridBagConstraints.BOTH;
    c.ipady = 40;      
    c.weightx = 1;
    c.weighty = 1;
    c.gridwidth = 2;
    c.gridheight = 1;
    c.gridx = 1;
    c.gridy = 1;
    container.add(textArea, c);

    textArea.setFont(new Font("Serif", Font.ITALIC, 16));
    textArea.setLineWrap(true);
    textArea.setWrapStyleWord(true);

    c.fill = GridBagConstraints.HORIZONTAL;
    c.ipady = 20; 
    c.weighty = 0;
    c.weightx = 0;
    c.anchor = GridBagConstraints.PAGE_END; 
    c.gridx = 1;
    c.gridwidth = 2;
    c.gridy = 2;
    container.add(infoPanel, c);

    infoPanel.setBorder(BorderFactory.createLineBorder(Color.black));
}


private static void createAndShowGUI() {
    JFrame frame = new JFrame("Grid test");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    addComponentsToPane(frame.getContentPane());
    frame.setSize(800,600);
    frame.setVisible(true);
}

public static void main(String[] args) {
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            createAndShowGUI();
        }
    });
}
}

- Joshua Alcock

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+1 对于SSCCE - nachokk

Answer 1

考虑使用 JToolBar，而不是 JPanel，因为它有自己的布局管理器，基本上已经做到了这一点。

以下是来自教程的图片...

查看如何使用工具栏获取更多详细信息。

- MadProgrammer

Answer 2

一种方法：将您的FlowLayout更改为更倾向于将其组件放置在左侧的布局：

panel = new JPanel(new FlowLayout(FlowLayout.LEADING));

- Hovercraft Full Of Eels