java - 如何在 JPanel 中添加 JButton？

Question

我想在此 GUI 的下部区域添加一个 JButton (panButton)，但我不知道必须将其添加到哪个元素。我尝试对多个元素执行 panButton.add(element) 但没有任何效果。

我无法理解面板的主要元素是什么。GUI 的显示方式如下: 这是代码:

    private void buildGUI() {
    setTitle("Avanzamento upload");
    setIconImage(Toolkit.getDefaultToolkit().getImage(ClientUpload.class.getResource("/clientupload/resources/logoRFI.gif")));

    addWindowListener(new java.awt.event.WindowAdapter() {
        @Override
        public void windowClosing(java.awt.event.WindowEvent evt) {
            formWindowClosing(evt);
        }
    });

    JLabel lblProgressAll = new JLabel("Totale: ");
    JLabel lblProgressCurrent = new JLabel("File attuale: ");
    JLabel lblTotalBytes = new JLabel("MB totali: ");
    JLabel lblCopiedBytes = new JLabel("MB copiati: ");
    lblTotalBytesValue = new JLabel("0 MB");
    lblCopiedBytesValue = new JLabel("0 MB");

    progressButton = new JButton("Interrompi"); //fc

    progressAll = new JProgressBar(0, 100);
    progressAll.setStringPainted(true);
    progressCurrent = new JProgressBar(0, 100);
    progressCurrent.setStringPainted(true);
    txtDetails = new JTextArea(5, 50);
    txtDetails.setEditable(false);
    DefaultCaret caret = (DefaultCaret) txtDetails.getCaret();
    caret.setUpdatePolicy(DefaultCaret.ALWAYS_UPDATE);
    JScrollPane scrollPane = new JScrollPane(txtDetails, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);

    JPanel contentPane = (JPanel) getContentPane();
    contentPane.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));

    JPanel panProgressLabels = new JPanel(new BorderLayout(0, 5));
    JPanel panProgressBars = new JPanel(new BorderLayout(0, 5));
    JPanel panCopyLabels = new JPanel(new BorderLayout(0, 5));
    JPanel panCopyFields = new JPanel(new BorderLayout(0, 5));

    panProgressLabels.add(lblProgressAll, BorderLayout.NORTH);
    panProgressLabels.add(lblProgressCurrent, BorderLayout.CENTER);
    panCopyLabels.add(lblTotalBytes, BorderLayout.NORTH);
    panCopyLabels.add(lblCopiedBytes, BorderLayout.CENTER);
    panCopyFields.add(lblTotalBytesValue, BorderLayout.NORTH);
    panCopyFields.add(lblCopiedBytesValue, BorderLayout.CENTER);
    panProgressBars.add(progressAll, BorderLayout.NORTH);
    panProgressBars.add(progressCurrent, BorderLayout.CENTER);

    JPanel panProgress = new JPanel(new BorderLayout(0, 5));
    panProgress.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createTitledBorder("Avanzamento"), BorderFactory.createEmptyBorder(5, 5, 5, 5)));
    JPanel panCopy = new JPanel(new BorderLayout(0, 5));
    panCopy.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createTitledBorder("Stato"), BorderFactory.createEmptyBorder(5, 5, 5, 5)));
    JPanel panDetails = new JPanel(new BorderLayout());
    panDetails.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createTitledBorder("Dettagli"), BorderFactory.createEmptyBorder(5, 5, 5, 5)));
    //fc
    JPanel panButton = new JPanel(new BorderLayout());
    panButton.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createTitledBorder(" "), BorderFactory.createEmptyBorder(5, 5, 5, 5)));

    panProgress.add(panProgressLabels, BorderLayout.LINE_START);
    panProgress.add(panProgressBars, BorderLayout.CENTER);
    panCopy.add(panCopyLabels, BorderLayout.LINE_START);
    panCopy.add(panCopyFields, BorderLayout.CENTER);
    panDetails.add(scrollPane, BorderLayout.CENTER);

    JPanel panUpper = new JPanel(new BorderLayout());
    panUpper.add(panProgress, BorderLayout.NORTH);
    panUpper.add(panCopy, BorderLayout.SOUTH);

    contentPane.add(panUpper, BorderLayout.NORTH);
    contentPane.add(panDetails, BorderLayout.CENTER);

    pack();
    setLocationRelativeTo(null);
}

我希望它出现在右侧的 Stato 区域或 Dettagli 区域下方。

有人可以帮助我吗？

Answer 1

panButton 是一个 JPanel，它永远不会添加到 GUI 中，因此如果您向其中添加某些内容，它也不会添加到可见的 GUI 中。

您需要将按钮添加到按钮面板，并将按钮面板添加到contentPane

JPanel panButton = new JPanel(new BorderLayout());
panButton.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createTitledBorder(" "), BorderFactory.createEmptyBorder(5, 5, 5, 5)));
panButton.add(element);  //Add button to panel
...
contentPane.add(panUpper, BorderLayout.NORTH);
contentPane.add(panDetails, BorderLayout.CENTER);
contentPane.add(panButton, BorderLayout.CENTER);  //Add panel to contentPane (which I assume is added to the frame at some point as I can see it's elements on the UI you posted)

或者只是使用 panCopy.add(element); 将其添加到“Stato”区域