在向CardLayout动态添加JPanel时，组件无法正确显示

Question

我希望有人能够帮助我解决以下问题。我正在创建一个Java桌面应用程序，其中我有一个包含两个JPanel的JPanel topicPanel; topicButtonsPanel，包含实现CardLayout的JButton createEntryButton和topicTabCardsPanel。单击createEntryButton时，我试图动态创建并添加一个包含JTextlabels，JTextFIelds和JButtons的新JPanel entryPanel。 topicPanel类中的action执行方法中使用的代码是：

private void createEntryButtonActionPerformed(java.awt.event.ActionEvent evt)    {                                                  
    EntryPanel entryPanel = new EntryPanel();
    add(entryPanel);

    CardLayout cards = (CardLayout) topicTabCardsPanel.getLayout();
    cards.addLayoutComponent(entryPanel, "entryPanelCard");
    cards.show(topicTabCardsPanel, "entryPanelCard");
}  

但是，尽管entryPanel已添加到topicPanel，但topicPanel中的组件未正确显示。只有JTextFields显示正确显示，JLabel根本不显示，JButton只在悬停时显示？我还有一个JTextArea，除了滚动条时，它不显示。

以下是topicPanel和entryPanel类的代码：

import java.awt.CardLayout;

public class TopicTab extends javax.swing.JPanel {

private ProjectPanel projectPanel;

/**
 * Creates new form TopicTab
 */
public TopicTab(ProjectPanel projectPanel) {
    initComponents();
    this.projectPanel = projectPanel;
}

public TopicTab() {
    initComponents();
}

public static void main(String args[]) {

    TopicTab topicTab = new TopicTab();
    topicTab.setVisible(true);
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    topicButtonsPanel = new javax.swing.JPanel();
    createEntryButton = new javax.swing.JButton();
    importEntryButton = new javax.swing.JButton();
    topicTabCardsPanel = new javax.swing.JPanel();
    timelinePanel = new Timeline.TimelinePanel();

    setMinimumSize(new java.awt.Dimension(1275, 672));
    setPreferredSize(new java.awt.Dimension(1275, 672));
    setLayout(new java.awt.BorderLayout());

    topicButtonsPanel.setBackground(new java.awt.Color(255, 255, 255));

    createEntryButton.setText("Create Entry");
    createEntryButton.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            createEntryButtonActionPerformed(evt);
        }
    });

    importEntryButton.setText("Import Entry");

    javax.swing.GroupLayout topicButtonsPanelLayout = new javax.swing.GroupLayout(topicButtonsPanel);
    topicButtonsPanel.setLayout(topicButtonsPanelLayout);
    topicButtonsPanelLayout.setHorizontalGroup(
        topicButtonsPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(topicButtonsPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(createEntryButton)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(importEntryButton)
            .addContainerGap(1071, Short.MAX_VALUE))
    );
    topicButtonsPanelLayout.setVerticalGroup(
        topicButtonsPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(topicButtonsPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addGroup(topicButtonsPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(createEntryButton)
                .addComponent(importEntryButton))
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
    );

    add(topicButtonsPanel, java.awt.BorderLayout.PAGE_START);

    topicTabCardsPanel.setLayout(new java.awt.CardLayout());

    javax.swing.GroupLayout timelinePanelLayout = new javax.swing.GroupLayout(timelinePanel);
    timelinePanel.setLayout(timelinePanelLayout);
    timelinePanelLayout.setHorizontalGroup(
        timelinePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 1275, Short.MAX_VALUE)
    );
    timelinePanelLayout.setVerticalGroup(
        timelinePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 627, Short.MAX_VALUE)
    );

    topicTabCardsPanel.add(timelinePanel, "card2");

    add(topicTabCardsPanel, java.awt.BorderLayout.CENTER);
}// </editor-fold>                        

private void createEntryButtonActionPerformed(java.awt.event.ActionEvent evt) {                                                  
    EntryPanel entryPanel = new EntryPanel();
    add(entryPanel);

    CardLayout cards = (CardLayout) topicTabCardsPanel.getLayout();
    cards.addLayoutComponent(entryPanel, "entryPanelCard");
    cards.show(topicTabCardsPanel, "entryPanelCard");
}                                                 

// Variables declaration - do not modify                     
private javax.swing.JButton createEntryButton;
private javax.swing.JButton importEntryButton;
private Timeline.TimelinePanel timelinePanel;
private javax.swing.JPanel topicButtonsPanel;
private javax.swing.JPanel topicTabCardsPanel;
// End of variables declaration                   
}


public class EntryPanel extends javax.swing.JPanel {

/**
 * Creates new form EntryViewPanel
 */
public EntryPanel() {
    initComponents();
}

/**
 * This method is called from within the constructor to initialise the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    createEntryDetails = new javax.swing.JPanel();
    jLabel2 = new javax.swing.JLabel();
    entryTitleLabel = new javax.swing.JLabel();
    entryDateLabel = new javax.swing.JLabel();
    entryNotesLabel = new javax.swing.JLabel();
    jScrollPane2 = new javax.swing.JScrollPane();
    entryNotesTextArea = new javax.swing.JTextArea();
    entryDayTextField = new javax.swing.JTextField();
    entryTitleTextField = new javax.swing.JTextField();
    entryMonthTextField = new javax.swing.JTextField();
    entryYearTextField = new javax.swing.JTextField();
    newEntryDateBackslashLabel = new javax.swing.JLabel();
    newEntryDateBackslashLabel1 = new javax.swing.JLabel();
    sourceDetailsTabbedPane = new javax.swing.JTabbedPane();
    addSourcePanel = new javax.swing.JPanel();
    addSourceLabel = new javax.swing.JLabel();
    buttonsPanel = new javax.swing.JPanel();
    createEntryButtonsPanel = new javax.swing.JPanel();
    createEntryButton = new javax.swing.JButton();
    backButton = new javax.swing.JButton();
    updateEntryButtonsPanel = new javax.swing.JPanel();
    backButton1 = new javax.swing.JButton();
    updateEntryButton = new javax.swing.JButton();

    setMaximumSize(new java.awt.Dimension(1045, 591));
    setMinimumSize(new java.awt.Dimension(1275, 672));
    setPreferredSize(new java.awt.Dimension(1275, 672));
    setLayout(new java.awt.BorderLayout());

    jLabel2.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N
    jLabel2.setText("Enter new entry details:");

    entryTitleLabel.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N
    entryTitleLabel.setText("Title:");

    entryDateLabel.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N
    entryDateLabel.setText("Date (dd/mm/yy):");

    entryNotesLabel.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N
    entryNotesLabel.setText("Notes:");

    entryNotesTextArea.setColumns(20);
    entryNotesTextArea.setFont(new java.awt.Font("Tahoma", 0, 14)); // NOI18N
    entryNotesTextArea.setRows(5);
    jScrollPane2.setViewportView(entryNotesTextArea);

    entryDayTextField.setFont(new java.awt.Font("Tahoma", 0, 14)); // NOI18N

    entryTitleTextField.setFont(new java.awt.Font("Tahoma", 0, 14)); // NOI18N

    entryMonthTextField.setFont(new java.awt.Font("Tahoma", 0, 14)); // NOI18N

    entryYearTextField.setFont(new java.awt.Font("Tahoma", 0, 14)); // NOI18N

    newEntryDateBackslashLabel.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N
    newEntryDateBackslashLabel.setText("/");

    newEntryDateBackslashLabel1.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N
    newEntryDateBackslashLabel1.setText("/");

    javax.swing.GroupLayout createEntryDetailsLayout = new javax.swing.GroupLayout(createEntryDetails);
    createEntryDetails.setLayout(createEntryDetailsLayout);
    createEntryDetailsLayout.setHorizontalGroup(
        createEntryDetailsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(createEntryDetailsLayout.createSequentialGroup()
            .addContainerGap()
            .addGroup(createEntryDetailsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(createEntryDetailsLayout.createSequentialGroup()
                    .addComponent(entryTitleLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 49, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(69, 69, 69)
                    .addComponent(entryTitleTextField, javax.swing.GroupLayout.PREFERRED_SIZE, 348, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(54, 54, 54)
                    .addComponent(entryDateLabel)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                    .addComponent(entryDayTextField, javax.swing.GroupLayout.PREFERRED_SIZE, 26, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                    .addComponent(newEntryDateBackslashLabel)
                    .addGap(9, 9, 9)
                    .addComponent(entryMonthTextField, javax.swing.GroupLayout.PREFERRED_SIZE, 26, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                    .addComponent(newEntryDateBackslashLabel1)
                    .addGap(10, 10, 10)
                    .addComponent(entryYearTextField, javax.swing.GroupLayout.PREFERRED_SIZE, 55, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 241, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGroup(createEntryDetailsLayout.createSequentialGroup()
                    .addGap(118, 118, 118)
                    .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 348, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addComponent(entryNotesLabel))
            .addContainerGap(437, Short.MAX_VALUE))
    );
    createEntryDetailsLayout.setVerticalGroup(
        createEntryDetailsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(createEntryDetailsLayout.createSequentialGroup()
            .addComponent(jLabel2)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addGroup(createEntryDetailsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(entryTitleLabel)
                .addComponent(entryTitleTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(entryDateLabel)
                .addComponent(entryDayTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(entryMonthTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(entryYearTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(newEntryDateBackslashLabel)
                .addComponent(newEntryDateBackslashLabel1))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addGroup(createEntryDetailsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(entryNotesLabel)
                .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(0, 9, Short.MAX_VALUE))
    );

    add(createEntryDetails, java.awt.BorderLayout.PAGE_START);

    addSourceLabel.setFont(new java.awt.Font("Tahoma", 0, 24)); // NOI18N
    addSourceLabel.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
    addSourceLabel.setText("Click here to add a new Source");
    addSourceLabel.setHorizontalTextPosition(javax.swing.SwingConstants.CENTER);

    javax.swing.GroupLayout addSourcePanelLayout = new javax.swing.GroupLayout(addSourcePanel);
    addSourcePanel.setLayout(addSourcePanelLayout);
    addSourcePanelLayout.setHorizontalGroup(
        addSourcePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(addSourcePanelLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(addSourceLabel, javax.swing.GroupLayout.DEFAULT_SIZE, 1250, Short.MAX_VALUE)
            .addContainerGap())
    );
    addSourcePanelLayout.setVerticalGroup(
        addSourcePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(addSourcePanelLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(addSourceLabel, javax.swing.GroupLayout.DEFAULT_SIZE, 437, Short.MAX_VALUE)
            .addContainerGap())
    );

    addSourceLabel.getAccessibleContext().setAccessibleName("addSourcePanel");

    sourceDetailsTabbedPane.addTab("add source", addSourcePanel);

    add(sourceDetailsTabbedPane, java.awt.BorderLayout.CENTER);
    sourceDetailsTabbedPane.getAccessibleContext().setAccessibleDescription("sourceDetailsTabbedPane");

    buttonsPanel.setMaximumSize(new java.awt.Dimension(1045, 68));
    buttonsPanel.setLayout(new java.awt.CardLayout());

    createEntryButtonsPanel.setMaximumSize(new java.awt.Dimension(1045, 68));
    createEntryButtonsPanel.setName("createEntryButtonsPanel");
    createEntryButtonsPanel.setPreferredSize(new java.awt.Dimension(1045, 68));

    createEntryButton.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N
    createEntryButton.setText("Create");

    backButton.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N
    backButton.setText("Back");

    javax.swing.GroupLayout createEntryButtonsPanelLayout = new javax.swing.GroupLayout(createEntryButtonsPanel);
    createEntryButtonsPanel.setLayout(createEntryButtonsPanelLayout);
    createEntryButtonsPanelLayout.setHorizontalGroup(
        createEntryButtonsPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(createEntryButtonsPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(backButton, javax.swing.GroupLayout.PREFERRED_SIZE, 143, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
            .addComponent(createEntryButton, javax.swing.GroupLayout.PREFERRED_SIZE, 141, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(971, Short.MAX_VALUE))
    );
    createEntryButtonsPanelLayout.setVerticalGroup(
        createEntryButtonsPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(createEntryButtonsPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addGroup(createEntryButtonsPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(backButton, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(createEntryButton, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addContainerGap(16, Short.MAX_VALUE))
    );

    buttonsPanel.add(createEntryButtonsPanel, "createEntryButtonsPanel");

    updateEntryButtonsPanel.setMaximumSize(new java.awt.Dimension(1045, 68));
    updateEntryButtonsPanel.setMinimumSize(new java.awt.Dimension(1045, 68));
    updateEntryButtonsPanel.setName("updateEntryButtonsPanel");
    updateEntryButtonsPanel.setPreferredSize(new java.awt.Dimension(1045, 68));

    backButton1.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N
    backButton1.setText("Back");

    updateEntryButton.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N
    updateEntryButton.setText("Update");

    javax.swing.GroupLayout updateEntryButtonsPanelLayout = new javax.swing.GroupLayout(updateEntryButtonsPanel);
    updateEntryButtonsPanel.setLayout(updateEntryButtonsPanelLayout);
    updateEntryButtonsPanelLayout.setHorizontalGroup(
        updateEntryButtonsPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(updateEntryButtonsPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(backButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 143, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
            .addComponent(updateEntryButton, javax.swing.GroupLayout.PREFERRED_SIZE, 141, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(971, Short.MAX_VALUE))
    );
    updateEntryButtonsPanelLayout.setVerticalGroup(
        updateEntryButtonsPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(updateEntryButtonsPanelLayout.createSequentialGroup()
            .addContainerGap()
            .addGroup(updateEntryButtonsPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(backButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(updateEntryButton, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addContainerGap(16, Short.MAX_VALUE))
    );

    buttonsPanel.add(updateEntryButtonsPanel, "updateEntryButtonsPanel");

    add(buttonsPanel, java.awt.BorderLayout.PAGE_END);
}// </editor-fold>                        


// Variables declaration - do not modify                     
private javax.swing.JLabel addSourceLabel;
private javax.swing.JPanel addSourcePanel;
private javax.swing.JButton backButton;
private javax.swing.JButton backButton1;
private javax.swing.JPanel buttonsPanel;
private javax.swing.JButton createEntryButton;
private javax.swing.JPanel createEntryButtonsPanel;
private javax.swing.JPanel createEntryDetails;
private javax.swing.JLabel entryDateLabel;
private javax.swing.JTextField entryDayTextField;
private javax.swing.JTextField entryMonthTextField;
private javax.swing.JLabel entryNotesLabel;
private javax.swing.JTextArea entryNotesTextArea;
private javax.swing.JLabel entryTitleLabel;
private javax.swing.JTextField entryTitleTextField;
private javax.swing.JTextField entryYearTextField;
private javax.swing.JLabel jLabel2;
private javax.swing.JScrollPane jScrollPane2;
private javax.swing.JLabel newEntryDateBackslashLabel;
private javax.swing.JLabel newEntryDateBackslashLabel1;
private javax.swing.JTabbedPane sourceDetailsTabbedPane;
private javax.swing.JButton updateEntryButton;
private javax.swing.JPanel updateEntryButtonsPanel;
// End of variables declaration                   
}

我正在使用NetBeans IDE 7.1.2和Java：1.7.0_04。

由于

Answer 1

所以看起来我已经解决了这个问题。而不是

add(entryPanel);

将entryPanel添加到topicTab面板，我应该将entryPanel添加到topicTabsCardPAnel

topicTabCardsPanel.add(entryPanel);

愚蠢的错误！