如何将 JPanel 中的组件向左对齐？答案

【问题标题】：How do I align components in a JPanel to the left?如何将 JPanel 中的组件向左对齐？
【发布时间】：2014-01-13 17:36:45
【问题描述】：

我已经为一个基本的文本编辑器创建了一个布局，我希望顶部栏的按钮对齐到左侧，顶部栏是一个 JPanel，它正在使用 FlowLayout 管理器。它位于使用 GridBag 布局管理器的网格内部。有什么建议？

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();
        }
    });
}
}

【问题讨论】：

+1 SSCCE

标签： java swing layout jpanel

【解决方案1】：

一种方法：将您的 FlowLayout 更改为更喜欢将其组件放置在左侧的方式：

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

【讨论】：

【解决方案2】：

考虑使用JToolBar 而不是JPanel，因为它有自己的布局管理器，基本上，它可以做到这一点。

以下教程中的图片...

查看How to use Tool Bars了解更多详情

【讨论】：