java - 使用 GridBagLayout 调整大小时防止组件散开

Question

编辑:每次我尝试添加 gui 标签时，它都会切换到 user-interface。有人介意解释/解决这个问题吗？

我希望客户端可以调整大小。我希望 JSeparator 在调整大小时填充框架的宽度，但我希望 JLabel 保持在字段旁边。

一开始是这样的，JLabel 与字段的距离太远了:

当我水平调整它时，结果是这样的:

这显然相差太远了。我用来设置这些组件的代码是:

public class LoginPanel extends JPanel {
    
    private JTextField userfield = new JTextField(10);
    private JPasswordField passfield = new JPasswordField(10);
    private JButton login = new JButton("Login");
    private JButton create = new JButton("Create Account");
    
    public LoginPanel() {
        setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        
        gbc.anchor = GridBagConstraints.CENTER;
        gbc.weightx = 1;
        gbc.gridx = 2;
        JLabel label = new JLabel("Username: ");
        add(label, gbc);
        
        gbc.gridx = 3;
        gbc.gridwidth = 2;
        add(userfield, gbc);
        
        gbc.gridy = 1;
        add(passfield, gbc);
        
        gbc.gridx = 2;
        label = new JLabel("Password: ");
        add(label, gbc);

        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.gridy = 2;
        gbc.gridx = 1;
        gbc.gridwidth = 5;
        add(new JSeparator(JSeparator.HORIZONTAL), gbc);
    }
}

(删减了一些内容，如有遗漏请告知) 我尝试过锚定，但我仍然不是 100% 熟悉 GridBagLayout(和约束)，所以我不确定我的尝试是否在正确的方向。

如何防止 Username: 和 Password: 标签从我的字段中移开，同时仍然能够调整大小？

此外，我想使用 GridBagLayout。我还有很多东西需要添加，我不想使用简单的布局，因为我需要灵 active 。

Answer 1

利用GridBagConstraints#anchor

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JSeparator;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class LogInTest {

    public static void main(String[] args) {
        new LogInTest();
    }

    public LogInTest() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new LoginPanel());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class LoginPanel extends JPanel {

        private JTextField userfield = new JTextField(10);
        private JPasswordField passfield = new JPasswordField(10);
        private JButton login = new JButton("Login");
        private JButton create = new JButton("Create Account");

        public LoginPanel() {
            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();

            gbc.anchor = GridBagConstraints.CENTER;
            gbc.weightx = 1;
            gbc.gridx = 2;
            gbc.anchor = GridBagConstraints.EAST;
            JLabel label = new JLabel("Username: ");
            add(label, gbc);

            gbc.anchor = GridBagConstraints.WEST;
            gbc.gridx = 3;
            gbc.gridwidth = 2;
            add(userfield, gbc);

            gbc.gridy = 1;
            add(passfield, gbc);

            gbc.anchor = GridBagConstraints.EAST;
            gbc.gridx = 2;
            label = new JLabel("Password: ");
            add(label, gbc);

            gbc.fill = GridBagConstraints.HORIZONTAL;
            gbc.gridy = 2;
            gbc.gridx = 1;
            gbc.gridwidth = 5;
            add(new JSeparator(JSeparator.HORIZONTAL), gbc);
        }
    }

}

您可能还想考虑使用复合布局，即将每个区域分隔到它自己的容器中，并专注于每个部分的单独布局需求，然后将它们全部构建到一个布局中