从 JList 中删除项目

Question

这是一个代码，我想更改 JList 项目，但是当我单击打开按钮并且 JList.removeAll() 运行时，我的 JList 没有删除项目... 有什么问题？

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;


public class JListTest {
    public static void main(String[] args) {
        String[] j = {"item1","item2","item3"};
        final JList list = new JList(j);

        JButton open = new JButton("open");
        open.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                list.removeAll();
            }
        });

        JFrame frame = new JFrame();
        frame.setSize(400, 400);
        Container con = frame.getContentPane();
        con.setLayout(new BorderLayout());
        con.add(open,BorderLayout.LINE_START);
        con.add(list,BorderLayout.CENTER);
        con.add(new JScrollPane(list));
        frame.setVisible(true);
    }
}

不信请测试

Answer 1

你的做法不对。对于你的构造函数new JList(j)，只有一个"read- only model"。

http://docs.oracle.com/javase/7/docs/api/javax/swing/JList.html It's easy to display an array or Vector of objects, using the JList constructor that automatically builds a read-only ListModel instance for you:

您应该使用真实模型，例如：

public class JListTest {


public static void main(String[] args) {

    DefaultListModel<String> model = new DefaultListModel<>();
    model.addElement("item1");
    model.addElement("item2");
    model.addElement("item3");
    final JList<String> list = new JList<String>(model);

    JButton open = new JButton("open");
    open.addActionListener(new ActionListener()

    {
        public void actionPerformed(ActionEvent e) {
            DefaultListModel<String> model = (DefaultListModel<String>) list.getModel();
            model.removeAllElements();
        }
    });
    JFrame frame = new JFrame();
    frame.setSize(400, 400);
    Container con = frame.getContentPane();
    con.setLayout(new BorderLayout());

    con.add(open, BorderLayout.LINE_START);
    con.add(list, BorderLayout.CENTER);
    con.add(new JScrollPane(list));
    frame.setVisible(true);

}

}

从 JList 中删除项目

Removing items from a JList

java

swing

jlist