java - 如何通过 JOptionPane 修改/添加字符串到 JList

Question

我需要帮助通过 JOptionPane 将字符串添加到 JList，这是迄今为止我的代码:

import javax.swing.JPanel; 
import java.awt.Dimension; 
import java.awt.Color; 
import javax.swing.JButton; 
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent; 
import javax.swing.JList; 
import javax.swing.BoxLayout; 
import javax.swing.JScrollPane; 
import java.awt.BorderLayout;
import javax.swing.JFrame; 
import javax.swing.JOptionPane; 
import java.util.ArrayList; 

/**
 * Write a description of class Front_Menu here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Front_Menu
{
    //Fields 
    private JFrame frame; 
    private JButton button1; 
    private JList list; 
    private JScrollPane listScroller; 
    private JPanel panel1; 
    private String title;

    /**
     * Construct the GUI
     */

    public void go()
    {
        frame = new JFrame("Flashcard Maker"); 
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

        Dimension frameSize = new Dimension(400, 300);
        frame.getContentPane().setPreferredSize(frameSize);        
        frame.getContentPane().setBackground(Color.WHITE);

        button1 = new JButton("New Set"); 
        button1.addActionListener(new ButtonListener());
        frame.getContentPane().add(BorderLayout.SOUTH, button1);

        String[] titleArray ={"Biology Set", title};
        list = new JList(titleArray); 

        listScroller = new JScrollPane(list);
        frame.getContentPane().add(BorderLayout.CENTER, listScroller); 

        frame.pack();
        frame.setVisible(true);
    }

    /**
     * Main Method 
     */

    public static void main(String[] args)
    {
        Front_Menu front_menu = new Front_Menu(); 
        front_menu.go(); 
    }

    /**
     * Inner class for the Button Listener 
     */

    private class ButtonListener implements ActionListener
    {
        /**
         * Override the actionPerformed Method 
         */

        public void actionPerformed(ActionEvent event)
        {
            title = JOptionPane.showInputDialog( 
                                null, 
                                "What is the title of your new set? "
                                );       
        }
    }
}

因此，在这个程序中，我有一个 JList，我想通过 JOptionPane 添加另一个字符串来修改它。它可以编译，但是当我单击按钮时它不会显示。

提前致谢!

Answer 1

运行代码后，您的 JOptionPane 弹出窗口对我来说很好。

要回答您的其他问题，请首先使用 DefaultListModel，它是可变的(允许您添加新元素)

public class Front_Menu {
//Fields 

    //...
    private DefaultListModel model;
    private JList list;
    //...

    /**
     * Construct the GUI
     */
    public void go() {
        //...
        String[] titleArray = {"Biology Set", title};
        model = new DefaultListModel();
        for (String title : titleArray) {
            model.addElement(title);
        }
        list = new JList(model);

然后在您的 ActionListener 中，将输入添加到模型中...

@Override
public void actionPerformed(ActionEvent event) {
    title = JOptionPane.showInputDialog(
            null,
            "What is the title of your new set? "
    );
    if (title != null) {
        model.addElement(title);
    }
}

看看How to Use Lists了解更多详情