GridBagLayout 元素在网格 Y 中重叠

Question

我正在从 Java Swing 学习如何使用GridBagLayout ...

在此示例中，我想在每一行中放置 4 个元素，如您在我的代码中所见：

        this.setLayout(new GridBagLayout());
        GridBagConstraints constraints = new GridBagConstraints();
        
        constraints.gridx = 0;
        constraints.gridy = 0;
        constraints.gridwidth = 1;
        constraints.gridheight = 1;
        //constraints.weighty = 1;
        constraints.anchor = GridBagConstraints.NORTHWEST;
        constraints.fill = constraints.HORIZONTAL;
        this.add(label1, constraints);
        constraints.weighty = 0.0; 
        
        constraints.gridx = 1;
        constraints.gridy = 1;
        constraints.gridwidth = 0;
        constraints.gridheight = 1;
        constraints.weighty = 1;
        constraints.anchor = GridBagConstraints.CENTER;
        constraints.fill = constraints.BOTH;
        this.add(label, constraints);
        constraints.weighty = 0.0; 
        
        JLabel precio = new JLabel();
        precio.setText("Precio    12345.5");
        constraints.gridx = 0;
        constraints.gridy = 2;
        constraints.gridwidth = 2;
        constraints.gridheight = 2;
        constraints.weighty = 1;
        constraints.fill = constraints.HORIZONTAL;
        constraints.anchor = GridBagConstraints.NORTH;
        this.add(precio, constraints);
        constraints.weighty = 0.0; 
        
        JLabel cantidad = new JLabel();
        cantidad.setText("Cantidad    ");
        constraints.gridx = 0;
        constraints.gridy = 3;
        constraints.gridwidth = 2;
        constraints.gridheight = 2;
        constraints.weightx = 1;
        constraints.fill = constraints.HORIZONTAL;
        constraints.anchor = GridBagConstraints.NORTH;
        this.add(cantidad, constraints);
        constraints.weighty = 0.0; 
        
        JTextField textfield = new JTextField();
        textfield.setPreferredSize(new Dimension(100 , 30));
        constraints.gridx = 2;
        constraints.gridy = 3;
        constraints.gridwidth = 2;
        constraints.gridheight = 2;
        constraints.weighty = 1;
        constraints.fill = constraints.HORIZONTAL;
        this.add(textfield, constraints);
        constraints.weighty = 0.0; 
        
        JButton boton = new JButton();
        boton.setText("Agregar");
        constraints.gridx = 0;
        constraints.gridy = 4;
        constraints.gridwidth = 2;
        constraints.gridheight = 2;
        constraints.weightx = 1;
        constraints.fill = constraints.HORIZONTAL;
        constraints.anchor = GridBagConstraints.NORTH;
        this.add(precio, constraints);
        constraints.weighty = 0.0; 

正如您在代码中看到的那样。

在第 0 行，我想放一个 JLabel

在第 1 行，我想放置一个带有图标的 JLabel

在第 2 行，我想放一个 JTextField

在第 3 行，我想在右侧放置一个 JTextfield 和 JTextField

最后在第 4 行，我想在列的中心放置一个 JButton。

但是当我运行 JFrame 时我得到了这个：

从第二行开始，我的组件重叠了，我不知道为什么。

也许我从GridBagLayout行为中遗漏了一些东西，因为我仍在学习如何使用它。

Answer 1

Oracle 有一个有用的教程，使用 Swing 创建 GUI 。 跳过学习 Swing 和 NetBeans IDE 部分。

您的代码有几个语法错误。 一旦我修复了这些问题，我就运行了你的代码。

我不确定你到底想要什么。 根据您的描述，我修改了您的代码以生成以下 GUI。

使用GridBagLayout时，某些参数您设置一次，其他参数您为每个 Swing 组件修改。 详见Oracle教程How to use GridBagLayout 。

下次，发布可以复制到 IDE 中并进行测试的可运行代码。

这是我使用的完整可运行代码。

import java.awt.BorderLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class GridBagLayoutExample implements Runnable {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new GridBagLayoutExample());
    }

    @Override
    public void run() {
        JFrame frame = new JFrame("Cell-33");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.add(createMainPanel(), BorderLayout.CENTER);

        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    public JPanel createMainPanel() {
        JPanel panel = new JPanel(new GridBagLayout());
        panel.setBorder(BorderFactory.createEmptyBorder(0, 5, 5, 5));

        GridBagConstraints constraints = new GridBagConstraints();

        constraints.anchor = GridBagConstraints.LINE_START;
        constraints.fill = GridBagConstraints.HORIZONTAL;
        constraints.insets = new Insets(0, 10, 5, 10);
        constraints.gridwidth = 1;
        constraints.gridheight = 1;

        constraints.gridx = 0;
        constraints.gridy = 0;
        JLabel label1 = new JLabel("Label1");
        panel.add(label1, constraints);

        constraints.gridx++;
        JLabel label = new JLabel("Label");
        panel.add(label, constraints);

        constraints.gridx++;
        JLabel precio = new JLabel();
        precio.setText("Precio    12345.5");
        panel.add(precio, constraints);

        constraints.gridx++;
        JLabel cantidad = new JLabel("Cantidad");
        panel.add(cantidad, constraints);

        constraints.gridx++;
        JTextField textfield = new JTextField(20);
        panel.add(textfield, constraints);

        constraints.gridx++;
        JButton boton = new JButton();
        boton.setText("Agregar");
        panel.add(boton, constraints);

        return panel;
    }

}