如何将每个 JPanel 向左或向右对齐到主 JPanel答案

【问题标题】：How to alignment each JPanel to left or to right into main JPanel如何将每个 JPanel 向左或向右对齐到主 JPanel
【发布时间】：2020-06-24 16:23:11
【问题描述】：

我希望我的应用看起来像这样：

我必须尝试使用

jpanel.setAlignmentX(JPanel.LEFT_ALIGNMENT);
jpanel.setAlignmentX(JPanel.RIGHT_ALIGNMENT);

但是当我将它添加到 main_JPanel 时，它适用于第一个 jpanel。 Show correctly 但是当我添加 JPanel2，JPanel3，... 然后 main_Panel 显示不正确，它显示：

这是我的函数创建每个 JPanel

public JPanel makeJpanel(String Mess, String username) {
        int height = 40;
        int width = 200;
        JTextPane textPane = new JTextPane();
        textPane.setEditable(false);
        StyledDocument doc = textPane.getStyledDocument();
        String rs = splitMess(Mess);
        Mess = rs.substring(2).trim();

        Style style = textPane.addStyle("I'm a Style", null);

        StyleConstants.setFontFamily(style, "Arial");
        StyleConstants.setBold(style, true);
        StyleConstants.setFontSize(style, 20);
        StyleConstants.setForeground(style, new Color(19, 51, 55));
        try {
            doc.insertString(doc.getLength(), Mess.trim(), style);
        } catch (BadLocationException e) {
        }
        height = (int) Math.round(textPane.getPreferredSize().getHeight());
        width = (int) Math.round(textPane.getPreferredSize().getWidth());

        //creat avatar
        JLabel ava = null;
        if (username.equals(this.userName)) {
            ava = new JLabel(label_myAvaProfile1.getIcon());
        } else {
            ava = new JLabel(label_avaYourFriends1.getIcon());
        }
        JLabel borderAva = new JLabel(border_label_avaYourFriends.getIcon());
        if (height < 40) {
            ava.setPreferredSize(new Dimension(40, 40));
            borderAva.setPreferredSize(new Dimension(40, 40));
        } else {
            ava.setPreferredSize(new Dimension(40, height));
            borderAva.setPreferredSize(new Dimension(40, height));
        }
        JLayeredPane lpAva = new JLayeredPane();
        lpAva.setLayout(new OverlayLayout(lpAva));
        lpAva.add(borderAva);
        lpAva.add(ava);

        JPanel panelChat = new JPanel();
        panelChat.setLayout(new BoxLayout(panelChat, BoxLayout.LINE_AXIS));
        panelChat.setBackground(Color.WHITE);
        panelChat.setPreferredSize(new Dimension(width + 40, height));
        panelChat.setMinimumSize(new Dimension(width + 40, height));
        panelChat.setMaximumSize(new Dimension(width + 40, height));
        if (username.equals(this.userName)) {
            panelChat.add(textPane);
            panelChat.add(lpAva);
            //NOTICE THIS
            panelChat.setAlignmentX(JPanel.LEFT_ALIGNMENT);
        } else if (username.equals(currentFriendUserName)) {
            panelChat.add(lpAva);
            panelChat.add(textPane);
            //NOTICE THIS
            panelChat.setAlignmentX(JPanel.RIGHT_ALIGNMENT);
        }

        resetPanelListFriends(panelChat);
        return panelChat;
    }

当我添加新的 Jpanel 时我调用的这个函数

public void renderPanelChatLog()
{
    JPanel panelChat = new JPanel();
        panelChat = makeJPanel(mess, username);
        if (panelChat != null) {
            panel_ChatLog.add(panelChat);
            panel_ChatLog.add(Box.createVerticalStrut(20));
        }
        resetPanelListFriends(panel_ChatLog);
}

对不起，我的英语，我只是新人...请帮助我！

【问题讨论】：

以后发布minimal reproducible example 来说明您的问题。我们对您的应用程序不感兴趣，只对演示问题的代码感兴趣。您如何创建子面板的详细信息与您的问题无关。您的问题是关于对齐，而不是添加到面板的组件。我的答案是“MRE”的形式。

标签： java swing alignment jpanel layout-manager

【解决方案1】：

这是一种方法：

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

public class BoxLayoutAligned
{
    private static void createAndShowGUI()
    {
        JLabel left = new JLabel( "Left Aligned" );
        Box leftBox = Box.createHorizontalBox();
        leftBox.add( left );
        leftBox.add( Box.createHorizontalGlue() );

        JLabel right = new JLabel( "Right Aligned" );
        Box rightBox = Box.createHorizontalBox();
        rightBox.add( Box.createHorizontalGlue() );
        rightBox.add( right );

        Box vertical = Box.createVerticalBox();
        vertical.setBorder( new EmptyBorder(0, 10, 0, 10) );
        vertical.add( leftBox );
        vertical.add( rightBox );

        JFrame frame = new JFrame("BoxLayout Aligned");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(vertical);
        frame.setSize(300, 300);
        frame.setLocationByPlatform( true );
        frame.setVisible( true );
    }

    public static void main(String[] args) throws Exception
    {
        java.awt.EventQueue.invokeLater( () -> createAndShowGUI() );
    }
}

通过添加“胶水”，您可以让添加到 Box 的其他组件左对齐或右对齐。

【讨论】：