如何在使用 Netbeans GUI 編輯器構建的項目的 JPanel 中添加 Jbutton？

Question

我正在使用 NetBeans IDE 來構建我的 GUI，當我單擊 jButton1 時，我想在 jPanel1 中插入一個按鈕 (jButtonMy)。 我在與可用的 jButton 關聯的回調中創建了按鈕 (jButtonMy)，但 Jpanel1 中沒有顯示任何內容。

Netbeans 生成我在下面復制/過去的詳細代碼

import java.awt.Dimension;
public class NewJFrame extends javax.swing.JFrame {

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

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jButton1 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jPanel1.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0)));

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 243, Short.MAX_VALUE)
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 168, Short.MAX_VALUE)
        );

        jButton1.setText("jButton1");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(64, 64, 64)
                        .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(layout.createSequentialGroup()
                        .addGap(161, 161, 161)
                        .addComponent(jButton1)))
                .addContainerGap(91, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 53, Short.MAX_VALUE)
                .addComponent(jButton1)
                .addGap(43, 43, 43))
        );

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

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
       jButtonMy = new javax.swing.JButton();
       jButtonMy.setText("jButtonMy");
       jButtonMy.setPreferredSize(new Dimension(100, 100));
       jPanel1.add(jButtonMy);
       jPanel1.revalidate();
       jPanel1.repaint();
    }                                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new NewJFrame().setVisible(true);
            }
        });
    }

   private javax.swing.JButton jButtonMy;

    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton1;
    private javax.swing.JPanel jPanel1;
    // End of variables declaration                   
}

Answer 1

最好不要忘記 setBounds，否則您將創建一個非常非常小的按鈕。 因此正確的代碼是

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
       jButtonMy = new javax.swing.JButton();
       jButtonMy.setText("jButtonMy");
       jPanel1.add(jButtonMy);
       jButtonMy.setVisible(true);
       jButtonMy.setBounds(10, 10, 100, 100);
       jPanel1.repaint();
       jPanel1.revalidate();
    }