Gridbag布局定位错误（Java）上的组件？

Question

我正在使用gridbag布局来灵活布局我的项目，但实际上它现在变得让我头疼，经过近5个小时的艰苦尝试后，我无法根据我的要求做正确的位置，plz为我弄清楚： -

public static void main(String[] args) {

        JFrame.setDefaultLookAndFeelDecorated(true);
        JFrame frame = new JFrame();
        //frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
        frame.setSize(300, 300);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setFont(f);
        frame.setTitle("Natural Language Processor");

        frame.setLayout(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();

            // Setting the label for the nlp            
            l = new JLabel("Natural Language Processor");
            l.setFont(f);
            c.weightx = 0.5;
            c.gridx = 0;
            c.gridy = 0;
            c.ipady = 20;
            c.fill = GridBagConstraints.NONE;
            c.anchor = GridBagConstraints.PAGE_START;
            frame.add(l, c);

            l1 = new JLabel("English");
            l.setFont(f1);
            c.weightx = 0.0;
            c.weighty = 1.0;
            c.gridy = 1;
            c.gridx = 0;

            //c.ipady = 20;
            c.fill = GridBagConstraints.NONE;
            c.anchor = GridBagConstraints.PAGE_START;

            frame.add(l1, c);

在上面的图片中，我希望标签“English”低于“自然语言处理器”标签的“自然”，而不是居中。

Answer 1

首先，不要忘记使用SwingUtilities.invokeLater(Runnable r)调用所有代码来在EDT中运行Swing代码。

有几种方法可以做到这一点，哪一个最好取决于你将在UI上放置什么。这是最简单的方法之一：

方式1

import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class TitleTestFrame extends JFrame
{

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

    public TitleTestFrame()
    {
        super("frame title");

        JLabel titleLabel = new JLabel("This is a centered title.");
        JLabel subtitleLabel = new JLabel("Subtitle");

        JPanel mainPanel = new JPanel(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();
        c.gridx = 0;
        c.gridy = 0;
        c.weightx = 0.0; //all components in the row with weightx = 0.0 keeps the components clump together in the center.
                           //This way the labels will be in the center of the panel.

        c.anchor = GridBagConstraints.FIRST_LINE_START; //FIRST_LINE makes the title and subtitle stay at the top of the frame.
                          //LINE_START make them be glued to the beginning of its column. However because the weightx = 0.0 the column is centered.


        mainPanel.add(titleLabel,  c);
        c.gridy = 1;
        c.weighty = 1.0;  // this weight must be put in the components under the titles so they don't get far from each other.
        mainPanel.add(subtitleLabel, c);


        add(mainPanel);

        setSize(new Dimension(400,300));
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        setVisible(true);
    }
}

结果：

我不太喜欢这种方式，因为它使用weightx = 0.0来保持标签居中，如果你需要在侧面放置更多的GUI元素，你需要将标签放在中心列中权重x 0.0和每侧的元素，权重x> 0.0。

例如，用以下代码替换上面的代码：

第2天

JPanel mainPanel = new JPanel(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
c.gridx = 1;
c.gridy = 0;
c.weightx = 0.0;
c.anchor = GridBagConstraints.FIRST_LINE_START;

mainPanel.add(titleLabel,  c);
c.gridy = 1;
mainPanel.add(subtitleLabel, c);

JPanel colorPanel = new JPanel();
colorPanel.setBackground(Color.red);
colorPanel.setOpaque(true);

JPanel colorPanel2 = new JPanel();
colorPanel2.setBackground(Color.gray);
colorPanel2.setOpaque(true);

c.weighty = 1.0;
c.gridy = 0;
c.gridx = 0;
c.weightx = 1.0;
c.gridheight = 2;
c.fill = GridBagConstraints.BOTH;
mainPanel.add(colorPanel, c);
c.gridx = 2;
mainPanel.add(colorPanel2, c);

add(mainPanel);

结果：

修改

使用gridbag布局进行良好布局的关键是了解如何创建网格。然后你只需要使用重量和锚来将组件放在每个单元格中。

这是我的2x3网格，在SECOND WAY（没有颜色）。

这是你的2x1网格

使用网格，您无法使用我的网格对齐标签的开头。