java - 扩展 JPanel 的类未在 JFrame 中显示

Question

我有两个类，InterfazextendsJFrame和Contenidoextends JPanel。我只是想将一个Contenido对象添加到Interfaz JFrame（我在Interfaz's 的构造函数中），但是当我运行代码（Interfaz是我的主类）时，会出现Interfaz's 的JFrame窗口，但Contenido JPanel不会出现在那里，即使我将它添加到JFrame. 有人知道为什么会这样吗？theInterfaz JFrame是空的，但Contenido JPanel有 aJLabel和 a JTextArea。我还这样做了，每当我单击JPanel.

抱歉，代码很长，我对这两个类都使用了 netbeans 的 GUI 构建器，它添加了很多代码。

Interfaz.java

package contenidodirectorio;

import javax.swing.JComponent;
import javax.swing.JPanel;

public class Interfaz extends javax.swing.JFrame {

    public Interfaz() {
        initComponents();
        contenidoPanel = new Contenido();
        add(contenidoPanel);
        contenidoPanel.setVisible(true);
        pack();
    }

    /**
     * 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() {

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 502, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 420, Short.MAX_VALUE)
        );

        pack();
    }// </editor-fold>                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(Interfaz.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Interfaz.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Interfaz.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Interfaz.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Interfaz().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    // End of variables declaration                   
    private JPanel contenidoPanel;
}

Contenido.java

package contenidodirectorio;

public class Contenido extends javax.swing.JPanel {

    public Contenido() {
        initComponents();
    }

    /**
     * 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() {

        jScrollPane1 = new javax.swing.JScrollPane();
        jTextArea1 = new javax.swing.JTextArea();
        jLabel1 = new javax.swing.JLabel();

        addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                formMouseClicked(evt);
            }
        });

        jTextArea1.setColumns(20);
        jTextArea1.setRows(5);
        jScrollPane1.setViewportView(jTextArea1);

        jLabel1.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT);
        jLabel1.setText("Directorio:");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
        this.setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(48, Short.MAX_VALUE)
                .addComponent(jLabel1)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 224, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(48, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(101, 101, 101)
                        .addComponent(jLabel1))
                    .addGroup(layout.createSequentialGroup()
                        .addGap(82, 82, 82)
                        .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 47, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(156, Short.MAX_VALUE))
        );
    }// </editor-fold>                        

    private void formMouseClicked(java.awt.event.MouseEvent evt) {                                  
        System.out.println("Clicked.");
    }                                 


    // Variables declaration - do not modify                     
    private javax.swing.JLabel jLabel1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTextArea jTextArea1;
    // End of variables declaration                   

标签： javaswingnetbeans