为什么 GridBagConstraints 将对象聚集在 JPanel 的中心？

Question

在下面的代码中，我创建了一个带有 JMenuBar 和 JPanel 的 JFrame，后者具有三个 JTextFields 和三个 JLabel。但是，JPanel 的所有组件都集中在中心。我在添加组件之前设置了布局，所以我不认为这是这个问题（我以前遇到过）。如果有人知道如何解决这个问题，我将不胜感激。

public class InterfaceWindow {
private static final Logger LOGGER = Logger.getLogger(DownloadWindow.class.getName());

private JButton helpJButton;
private JButton copyToClipBoardJButton;
private JButton enterJButton;
private JButton selectFileJButton;
private JLabel pathJLabel;
private JLabel jobNameJLabel;
private JLabel emailJLabel;
private JTextField pathJTextField;
private JTextField jobNameJTextField;
private JTextField emailJTextField;
private JTextArea transcriptionJTextArea;
private JMenu accountJMenu;
private JMenu jobsJMenu;
private JMenu helpJMenu;
private JMenuBar toolBarJMenuBar = new JMenuBar();
private JMenuItem uploadYouTubeJMenuItem;
private JMenuItem uploadFileJMenuItem;
private JMenuItem downloadJMenuItem;
private JMenuItem helpJMenuItem;
private GridBagConstraints panelGbc = new GridBagConstraints();
private GridBagConstraints frameGbc = new GridBagConstraints();
private JPanel interfaceJPanel = new JPanel();
private String emptyField = "default";
private String filePath = "default";

public JButton getHelpJButton() {
    return helpJButton;
}

public JButton getCopyToClipBoardJButton() {
    return copyToClipBoardJButton;
}

public JButton getEnterJButton() {
    return enterJButton;
}

public JButton getSelectFileJButton() {
    return selectFileJButton;
}

public JFrame setInterfaceWindow() {
    JFrame interfaceJFrame = new JFrame();
    frameGbc.fill = GridBagConstraints.HORIZONTAL;
    interfaceJPanel = setInterfaceJPanel();

    interfaceJFrame.getContentPane().setLayout(new GridBagLayout());
    interfaceJFrame.setLayout(new GridBagLayout());
    interfaceJFrame.setDefaultCloseOperation(EXIT_ON_CLOSE);
    interfaceJFrame.setTitle("Audio Transcribe");
    interfaceJFrame.setSize(800, 800);
    interfaceJFrame.setLocationRelativeTo(null);
    interfaceJFrame.setJMenuBar(setToolBar(toolBarJMenuBar));
    interfaceJFrame.add(interfaceJPanel, frameGbc);
    interfaceJFrame.setVisible(true);

    return interfaceJFrame;
}

private JPanel setInterfaceJPanel() {
    panelGbc.fill = GridBagConstraints.HORIZONTAL;
    panelGbc.insets.bottom = 1;
    panelGbc.insets.top = 2;
    panelGbc.insets.right = 1;
    panelGbc.insets.left = 1;
    panelGbc.weightx = 1;
    panelGbc.weighty = 1;

    interfaceJPanel.setLayout(new GridBagLayout());
    interfaceJPanel.setSize(800, 700);
    setJobName(interfaceJPanel);
    setPath(interfaceJPanel);
    setEmail(interfaceJPanel);
    setButtons(interfaceJPanel);
    setTextArea(interfaceJPanel);
    setAction();

    return interfaceJPanel;
}

public JMenuBar setToolBar(JMenuBar toolBarJMenuBar) {
    accountJMenu = new JMenu("Accounts");
    jobsJMenu = new JMenu("Jobs");
    helpJMenu = new JMenu("Help");

    toolBarJMenuBar.add(accountJMenu);
    toolBarJMenuBar.add(jobsJMenu);
    toolBarJMenuBar.add(helpJMenu);

    downloadJMenuItem = new JMenuItem("Download");
    uploadFileJMenuItem = new JMenuItem("Upload file");
    uploadYouTubeJMenuItem = new JMenuItem("Upload from YouTube");
    helpJMenuItem = new JMenuItem("Help");

    jobsJMenu.add(downloadJMenuItem);
    jobsJMenu.addSeparator();
    jobsJMenu.add(uploadFileJMenuItem);
    jobsJMenu.addSeparator();
    jobsJMenu.add(uploadYouTubeJMenuItem);
    helpJMenu.add(helpJMenuItem);

    return toolBarJMenuBar;
}

private void setEmail(JPanel interfaceJPanel) {
    JLabel emailLabel = new JLabel("Email:");

    panelGbc.gridx = 1;
    panelGbc.gridy = 3;
    panelGbc.gridwidth = 1;
    panelGbc.gridheight = 1;
    interfaceJPanel.add(emailLabel, panelGbc);

    emailJTextField = new JTextField();

    emailJTextField.setText(emptyField);
    panelGbc.gridx = 2;
    panelGbc.gridy = 3;
    panelGbc.gridwidth = 3;
    panelGbc.gridheight = 1;
    interfaceJPanel.add(emailJTextField, panelGbc);
}

private void setPath(JPanel interfaceJPanel) {
    JLabel filePathLabel = new JLabel("File path:");

    panelGbc.gridx = 1;
    panelGbc.gridy = 0;
    panelGbc.gridwidth = 1;
    panelGbc.gridheight = 1;
    interfaceJPanel.add(filePathLabel, panelGbc);

    pathJTextField = new JTextField();
    pathJTextField.setText(filePath);
    panelGbc.gridx = 2;
    panelGbc.gridy = 0;
    panelGbc.gridwidth = 2;
    panelGbc.gridheight = 1;
    interfaceJPanel.add(pathJTextField, panelGbc);
}

private void setJobName(JPanel interfaceJPanel) {
    JLabel jobNameLabel = new JLabel("Job name:");

    panelGbc.gridx = 1;
    panelGbc.gridy = 2;
    panelGbc.gridwidth = 1;
    panelGbc.gridheight = 1;
    interfaceJPanel.add(jobNameLabel, panelGbc);

    jobNameJTextField = new JTextField();
    jobNameJTextField.setText(emptyField);
    panelGbc.gridx = 2;
    panelGbc.gridy = 2;
    panelGbc.gridwidth = 2;
    panelGbc.gridheight = 1;
    interfaceJPanel.add(jobNameJTextField, panelGbc);
}

private void setAction() {
}

private void setTextArea(JPanel interfaceJPanel) {
}

private void setButtons(JPanel interfaceJPanel) {
}
}

Answer 1

这是因为您使用 GridBagLayout 嵌套了两个 JPanel，并且在将内部 JPanel 添加到外部面板时，您的 frameGbc 约束没有设置 weightx 或 weighty，使内部 JPanel 居中。内部 JPanel 的大小将调整为其 preferredSize，即尺寸尽可能小，并将居中。

最好不要这样做。而是让 JFrame 继续使用 BorderLayout，并使用 JPanel 添加 GridBagLayout BorderLayout.CENTER，或者不要不必要地嵌套 JPanels，只给 contentPane 一个 GridBagLayout。

为什么 GridBagConstraints 将对象聚集在 JPanel 的中心？

Why is GridBagConstraints gathering the objects in the centre of the JPanel?

java

swing

jpanel

jframe

gridbaglayout