如何实现组合框的多选功能？

Question

我要做的组合框，下面是多个复选框（JCheckBox），支持多选，选中的返回到上面的结果栏。形式如下，（田）代表选中
 
------------------
 a,b,c             
__________________\/  田  a
  田  b
  田  c
  口  d 请高手们指点一二，如有案例请提供链接，谢谢！
  

Answer 1

/*
 * JCheckBoxDemo.java
 *
 * Created on 2006年12月22日, 下午12:59
 */package wqlgui;import java.util.ArrayList;
import javax.swing.JCheckBox;/**
 *
 * @author  zwql
 */
public class JCheckBoxDemo extends javax.swing.JFrame {
    
    /** Creates new form JCheckBoxDemo */
    public JCheckBoxDemo() {
        initComponents();
        addActionListener(jCheckBox1);
        addActionListener(jCheckBox2);
        addActionListener(jCheckBox3);
        addActionListener(jCheckBox4);
        addActionListener(jCheckBox5);
    }
    
    public void addActionListener(JCheckBox checkbox){
        final JCheckBox c;
        c=checkbox;
        checkbox.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                checkboxActionPerformed(evt,c);
            }
        });
    }
    
    public void checkboxActionPerformed(java.awt.event.ActionEvent evt,JCheckBox checkbox){
        StringBuffer sbuffer = new StringBuffer();
        if(jCheckBox1.isSelected()){
            sbuffer.append(jCheckBox1.getText()+",");
        }
        if(jCheckBox2.isSelected()){
            sbuffer.append(jCheckBox2.getText()+",");
        }
        if(jCheckBox3.isSelected()){
            sbuffer.append(jCheckBox3.getText()+",");
        }
        if(jCheckBox4.isSelected()){
            sbuffer.append(jCheckBox4.getText()+",");
        }
        if(jCheckBox5.isSelected()){
            sbuffer.append(jCheckBox5.getText()+",");
        }
        String s = sbuffer.toString();
        jTextField1.setText(s.substring(0,s.length()-1));
    }
    
    /** 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.
     */
    // <editor-fold defaultstate="collapsed" desc=" 生成的代码 ">
    private void initComponents() {
        jTextField1 = new javax.swing.JTextField();
        jPanel1 = new javax.swing.JPanel();
        jCheckBox3 = new javax.swing.JCheckBox();
        jCheckBox1 = new javax.swing.JCheckBox();
        jCheckBox2 = new javax.swing.JCheckBox();
        jCheckBox4 = new javax.swing.JCheckBox();
        jCheckBox5 = new javax.swing.JCheckBox();        getContentPane().setLayout(null);        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        getContentPane().add(jTextField1);
        jTextField1.setBounds(0, 0, 162, 19);        jPanel1.setLayout(null);        jCheckBox3.setText("c");
        jCheckBox3.setBorder(javax.swing.BorderFactory.createEmptyBorder(0, 0, 0, 0));
        jCheckBox3.setMargin(new java.awt.Insets(0, 0, 0, 0));
        jPanel1.add(jCheckBox3);
        jCheckBox3.setBounds(0, 40, 162, 15);        jCheckBox1.setText("a");
        jCheckBox1.setBorder(javax.swing.BorderFactory.createEmptyBorder(0, 0, 0, 0));
        jCheckBox1.setMargin(new java.awt.Insets(0, 0, 0, 0));
        jCheckBox1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jCheckBox1ActionPerformed(evt);
            }
        });        jPanel1.add(jCheckBox1);
        jCheckBox1.setBounds(0, 0, 162, 15);        jCheckBox2.setText("b");
        jCheckBox2.setBorder(javax.swing.BorderFactory.createEmptyBorder(0, 0, 0, 0));
        jCheckBox2.setMargin(new java.awt.Insets(0, 0, 0, 0));
        jPanel1.add(jCheckBox2);
        jCheckBox2.setBounds(0, 15, 162, 20);        jCheckBox4.setText("d");
        jCheckBox4.setBorder(javax.swing.BorderFactory.createEmptyBorder(0, 0, 0, 0));
        jCheckBox4.setMargin(new java.awt.Insets(0, 0, 0, 0));
        jPanel1.add(jCheckBox4);
        jCheckBox4.setBounds(0, 60, 160, 15);        jCheckBox5.setText("e");
        jCheckBox5.setBorder(javax.swing.BorderFactory.createEmptyBorder(0, 0, 0, 0));
        jCheckBox5.setMargin(new java.awt.Insets(0, 0, 0, 0));
        jPanel1.add(jCheckBox5);
        jCheckBox5.setBounds(0, 80, 160, 15);        getContentPane().add(jPanel1);
        jPanel1.setBounds(0, 19, 162, 110);        pack();
    }// </editor-fold>    private void jCheckBox1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO 将在此处添加您的处理代码：
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
               JCheckBoxDemo demo =  new JCheckBoxDemo();
               demo.setSize(80,160);
               demo.setVisible(true);
            }
        });
    }
    
    // 变量声明 - 不进行修改
    public javax.swing.JCheckBox jCheckBox1;
    public javax.swing.JCheckBox jCheckBox2;
    public javax.swing.JCheckBox jCheckBox3;
    public javax.swing.JCheckBox jCheckBox4;
    public javax.swing.JCheckBox jCheckBox5;
    public javax.swing.JPanel jPanel1;
    public javax.swing.JTextField jTextField1;
    // 变量声明结束
    
}

Answer 2

public void addActionListener(JCheckBox checkbox){
        final JCheckBox c;
        c=checkbox;
        checkbox.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                checkboxActionPerformed(evt,c);
            }
        });
    }这个方法中变量checkbox ， c 可以去掉，没用

Answer 3

这位兄弟，非常感谢你的答复！你的答案很有参考价值！可能是我没有把需求解释清楚，你的答案并不满足我的需求。我要的效果是一个组合框点击右边那个箭头后弹出下拉菜单，下拉的弹出菜单要求有你程序里的A B C D (复选框）选项，并且支持多选，选中的返回到上面的结果栏，至于选完后如何隐藏的问题，可以再点击那个箭头隐藏。