运行java应用程序后创建并显示标签

Question

我已经解决了2天的问题,这对我来说会很头疼!我使用swing为我的应用程序创建GUI.我想通过单击按钮运行代码后向我的面板添加标签,但我不能.请帮我解决这个问题.大部分代码都是由swing自动生成的,而不是我编写的代码.

package javaapplication1;

import java.awt.Color;
import javax.swing.SwingConstants;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.*;

public class RandomWordGUI extends javax.swing.JFrame {

/** Creates new form RandomWordGUI */
public RandomWordGUI() {
    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() {

    jPanel1 = new javax.swing.JPanel();
    jButton1 = new javax.swing.JButton();
    jLabel1 = new javax.swing.JLabel();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

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

    jLabel1.setText("jLabel1");

    javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(jPanel1Layout.createSequentialGroup()
                    .addGap(155, 155, 155)
                    .addComponent(jButton1))
                .addGroup(jPanel1Layout.createSequentialGroup()
                    .addGap(172, 172, 172)
                    .addComponent(jLabel1)))
            .addContainerGap(172, Short.MAX_VALUE))
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
            .addGap(70, 70, 70)
            .addComponent(jLabel1)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(jButton1)
            .addGap(91, 91, 91))
    );

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(jPanel1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
            .addContainerGap(186, Short.MAX_VALUE)
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, 114, javax.swing.GroupLayout.PREFERRED_SIZE))
    );

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

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         

    JLabel jLabel2 = new JLabel();
    jLabel2.setText("this is a label");
    this.jPanel1.add(jLabel2);
    this.jPanel1.repaint();
    this.jPanel1.revalidate();


}                                        

/**
* @param args the command line arguments
*/
public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {


        public void run() {
            new RandomWordGUI().setVisible(true);


        }
        RandomWordGUI randWord=new RandomWordGUI();



    });
}

// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
private javax.swing.JPanel jPanel1;
// End of variables declaration

}

Answer 1

您正在尝试使用 添加到面板GroupLayout。动态添加将非常棘手（如果可能的话），我不建议这样做。我建议JPanel向该窗格添加一个帮助器，并将任何新组件添加到该帮助器面板。

编辑：

要清除所使用的解决方案：JPanel使用表单编辑器添加了一个助手（jPanel3在下面的代码中）。表单设计器默认GroupLayout也使用添加的面板，这会导致与首先要解决的问题相同，因此辅助面板的布局管理器更改为FlowLayout. 操作代码最终非常简单：

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
    JLabel jLabel2 = new JLabel();
    jLabel2.setText("this is a label");
    this.jPanel3.add(jLabel2);
    this.jPanel3.revalidate();
}