Question

我试图在单击按钮时在面板内部显示一组两个JTextfields（并排）。问题是像Flowlayout这样的东西会让我的文本字段在整个地方移动（它们排成一行或一列），而Gridlayout会使文本字段太大。我已经调查了Springlayout和Grouplayout，但是这些布局似乎没有一种直接的方式来在运行时添加一个组件（加上代码看起来非常麻烦，如下例所示）。

这是我试图用布局实现的一个例子...运行代码并注意当你调整窗口大小时JTextfields的反应（添加字段按钮按钮不起作用，因为我不确定如何使用Grouplayout将组件添加到面板中：

GoodLayout.java

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.GroupLayout;
import javax.swing.GroupLayout.Alignment;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.LayoutStyle.ComponentPlacement;
import javax.swing.border.EmptyBorder;

public class GoodLayout extends JFrame {

    private JPanel contentPane;
    private JTextField textField;
    private JTextField textField_1;
    private JTextField textField_2;
    private JTextField textField_3;
    private JTextField textField_4;
    private JTextField textField_5;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    GoodLayout frame = new GoodLayout();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public GoodLayout() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 383, 328);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(new BorderLayout(0, 0));

        JButton buttonAddFields = new JButton("+ Add Set of Fields +");
        buttonAddFields.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println("Add a set of fields to the panel");

            }
        });
        contentPane.add(buttonAddFields, BorderLayout.SOUTH);

        JPanel panel = new JPanel();
        contentPane.add(panel, BorderLayout.CENTER);

        textField = new JTextField();
        textField.setColumns(10);

        textField_1 = new JTextField();
        textField_1.setColumns(10);

        textField_2 = new JTextField();
        textField_2.setColumns(10);

        textField_3 = new JTextField();
        textField_3.setColumns(10);

        textField_4 = new JTextField();
        textField_4.setColumns(10);

        textField_5 = new JTextField();
        textField_5.setColumns(10);
        GroupLayout gl_panel = new GroupLayout(panel);
        gl_panel.setHorizontalGroup(
            gl_panel.createParallelGroup(Alignment.LEADING)
                .addGroup(gl_panel.createSequentialGroup()
                    .addContainerGap()
                    .addGroup(gl_panel.createParallelGroup(Alignment.LEADING)
                        .addGroup(gl_panel.createSequentialGroup()
                            .addComponent(textField, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                            .addPreferredGap(ComponentPlacement.RELATED)
                            .addComponent(textField_1, GroupLayout.DEFAULT_SIZE, 518, Short.MAX_VALUE))
                        .addGroup(gl_panel.createSequentialGroup()
                            .addComponent(textField_2, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                            .addPreferredGap(ComponentPlacement.RELATED)
                            .addComponent(textField_3, GroupLayout.DEFAULT_SIZE, 518, Short.MAX_VALUE))
                        .addGroup(gl_panel.createSequentialGroup()
                            .addComponent(textField_4, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                            .addPreferredGap(ComponentPlacement.RELATED)
                            .addComponent(textField_5, GroupLayout.DEFAULT_SIZE, 518, Short.MAX_VALUE)))
                    .addContainerGap())
        );
        gl_panel.setVerticalGroup(
            gl_panel.createParallelGroup(Alignment.LEADING)
                .addGroup(gl_panel.createSequentialGroup()
                    .addContainerGap()
                    .addGroup(gl_panel.createParallelGroup(Alignment.BASELINE)
                        .addComponent(textField, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                        .addComponent(textField_1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
                    .addPreferredGap(ComponentPlacement.RELATED)
                    .addGroup(gl_panel.createParallelGroup(Alignment.BASELINE)
                        .addComponent(textField_2, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                        .addComponent(textField_3, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
                    .addPreferredGap(ComponentPlacement.RELATED)
                    .addGroup(gl_panel.createParallelGroup(Alignment.BASELINE)
                        .addComponent(textField_4, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                        .addComponent(textField_5, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
                    .addContainerGap(287, Short.MAX_VALUE))
        );
        panel.setLayout(gl_panel);
    }

}

上面代码中的重要部分是actionPerformed方法......当我点击按钮并出现一对文本字段时，我真的很想找到一个看起来不错的简单解决方案（GUI布局方面）。也许这有更好的布局？我使用Eclipse插件WindowBuilder来构建上面的代码，并且我尝试了所有看起来合理的不同布局选项。

有关如何更好地解决此问题的任何想法或技巧都值得赞赏

谢谢，Dan

Answer 1

不要丢弃GroupLayout经理 - 它是一个非常强大的布局管理器并且是为数不多的管理者之一。但是，它不适用于动态布局结构布局的方式。我们必须完全重做我们的布局和做临时计算。

为此，我们可以轻松使用MigLayout。 MigLayout是第三方布局经理，也做得很好。它易于使用且功能强大。

package com.zetcode;

import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import net.miginfocom.swing.MigLayout;

public class GoodLayout2 extends JFrame {

    private JPanel pnl;

    public GoodLayout2() {

        initUI();

        setTitle("MigLayout solution");
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    private void initUI() {

        JButton addBtn = new JButton("Add");
        addBtn.addActionListener(new AddAction());

        pnl = new JPanel(new MigLayout("ins dialog, wrap 2"));
        pnl.add(addBtn, "span 2, center");
        pnl.add(new JTextField(10));
        pnl.add(new JTextField(10), "pushx, growx");
        pnl.add(new JTextField(10));
        pnl.add(new JTextField(10), "pushx, growx");
        pnl.add(new JTextField(10));
        pnl.add(new JTextField(10), "pushx, growx");

        add(pnl);
        pack();

    }

    private class AddAction extends AbstractAction {

        @Override
        public void actionPerformed(ActionEvent e) {
            pnl.add(new JTextField(10));
            pnl.add(new JTextField(10), "pushx, growx");
            pnl.doLayout();
            pnl.repaint();
        }

    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                GoodLayout2 ex = new GoodLayout2();
                ex.setVisible(true);
            }
        });
    }
}

我已将按钮放在窗口的北部，因为代码然后稍微复杂一点。

Good layout

在运行时将一组JTextField添加到面板，不同的布局管理器

GoodLayout.java

1 个答案: