JList - 列表选择监听器

Question

我想将侦听器添加到 jlist 中。但项目会动态添加到 jlist 中。 所以我无法注册监听器。 并且事件不会触发。 任何人都可以帮助我吗？？？ 如果你有任何例子请联系我。 我的电子邮件 ID [电子邮件受保护]
这是我的代码：

DefaultListModel f=new DefaultListModel();
DefaultListModel sf=new DefaultListModel();

public Jlistdemo() {
    initComponents();

    System.out.println("hi");
    for(int i=0;i<10;i++)
    {
        f.addElement("hello"+i);
        //System.out.println("helloo"+i);
    }
    fields=new JList(f);
    jScrollPane1.setViewportView(fields);

}


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

    jScrollPane1 = new javax.swing.JScrollPane();
    fields = new javax.swing.JList();
    jScrollPane2 = new javax.swing.JScrollPane();
    sel_fields = new javax.swing.JList();
    jButton1 = new javax.swing.JButton();
    jButton2 = new javax.swing.JButton();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    fields.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
    jScrollPane1.setViewportView(fields);

    sel_fields.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
    sel_fields.addListSelectionListener(new javax.swing.event.ListSelectionListener() {
        public void valueChanged(javax.swing.event.ListSelectionEvent evt) {
            sel_fieldsValueChanged(evt);
        }
    });
    jScrollPane2.setViewportView(sel_fields);

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

    jButton2.setText("<");
    jButton2.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton2ActionPerformed(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()
            .addGap(40, 40, 40)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 89, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(jButton1, javax.swing.GroupLayout.Alignment.TRAILING)
                .addComponent(jButton2, javax.swing.GroupLayout.Alignment.TRAILING))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
            .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 109, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(91, 91, 91))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(31, 31, 31)
                        .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(layout.createSequentialGroup()
                        .addGap(60, 60, 60)
                        .addComponent(jButton1)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jButton2))))
            .addContainerGap(68, Short.MAX_VALUE))
    );

    pack();
}

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
    if(fields.getSelectedValue()!=null)
    {
        int i=fields.getSelectedIndex();

        sf.addElement(fields.getSelectedValue());
        f.removeElement(fields.getSelectedValue());
        sel_fields=new JList(sf);
        sel_fields.setSelectionMode(ListSelectionModel.SINGLE_SELECTION );
        jScrollPane2.setViewportView(sel_fields);
        fields.setSelectedIndex(i);
        jScrollPane2.revalidate();
        jScrollPane2.repaint();
    }
}

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
    if(sel_fields.getSelectedValue()!=null)
    {
        int i=sel_fields.getSelectedIndex();
        f.addElement(sel_fields.getSelectedValue());
        sf.removeElementAt(sel_fields.getSelectedIndex());
        sel_fields.setSelectedIndex(i);
    }

}

private void sel_fieldsValueChanged(javax.swing.event.ListSelectionEvent evt) {
        System.out.println("fired");
}
public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {

        public void run() {
            new Jlistdemo().setVisible(true);
        }
    });
}

private javax.swing.JList fields;
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JScrollPane jScrollPane2;
private javax.swing.JList sel_fields;

Answer 1

错误是构造函数中的以下行：

 fields = new JList(f)

用它替换 initComponents 中创建的列表

Answer 2

您将列表的创建与添加数据分开。

并且您不需要跟踪选定的字段，该列表将为您完成此操作。

另外，更好的名称将有助于使代码更清晰。