下面是我的代码，我已经尝试过每件事。我尝试添加 getSelectedItem() 等。一切都无济于事，ComboBox 只能使用一次，而且它甚至不会更新。各位帮帮我吧!
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.*;
import javax.swing.*;
public class MainClass extends JFrame implements ActionListener {
String[] AmtOfPpl = {"1", "2", "3", "4"};
private JLabel jlabel = new JLabel("Please select a table:");
private JButton a01 = new JButton("A01");
private JButton a02 = new JButton("A02");
private JButton a03 = new JButton("A03");
private JButton a04 = new JButton("A04");
private JButton a05 = new JButton("A05");
private JButton a06 = new JButton("A06");
private JButton a07 = new JButton("A07");
private JButton a08 = new JButton("A08");
private JButton a09 = new JButton("A09");
private JButton a10 = new JButton("A10");
private JButton c01 = new JButton("C01");
private JButton c02 = new JButton("C02");
private JButton c03 = new JButton("C03");
private JButton c04 = new JButton("C04");
private JButton c05 = new JButton("C05");
private JButton c06 = new JButton("C06");
private JButton c07 = new JButton("C07");
private JButton c08 = new JButton("C08");
private JButton c09 = new JButton("C09");
private JButton c10 = new JButton("C10");
private JButton c11 = new JButton("C11");
private JButton c12 = new JButton("C12");
private JLabel FstName = new JLabel("*First Name: ");
private JLabel LstName = new JLabel("*Last Name: ");
private JLabel Addrss = new JLabel("Address: ");
private JLabel PstlCode = new JLabel("Postal Code: ");
private JLabel HndPne = new JLabel("*Handphone No.: ");
private JLabel AoP = new JLabel("*Amount of People: ");
private JLabel Mndtry = new JLabel("Fields marked with * are mandatory.");
private JTextField FName = new JTextField();
private JTextField LName = new JTextField();
private JTextField Addr = new JTextField();
private JTextField PCode = new JTextField();
private JTextField HP = new JTextField();
private JComboBox<?> AmtPpl = new JComboBox<Object>(AmtOfPpl);
public MainClass() {
JPanel p1 = new JPanel();
p1.setLayout(new GridLayout(2,5,10,25));
p1.add(a01);
p1.add(a02);
p1.add(a03);
p1.add(a04);
p1.add(a05);
p1.add(a10);
p1.add(a09);
p1.add(a08);
p1.add(a07);
p1.add(a06);
JPanel p2 = new JPanel();
p2.setLayout(new GridLayout(6,2,2,2));
p2.add(c01);
p2.add(c02);
p2.add(c03);
p2.add(c04);
p2.add(c05);
p2.add(c06);
p2.add(c07);
p2.add(c08);
p2.add(c09);
p2.add(c10);
p2.add(c11);
p2.add(c12);
a01.addActionListener(this);
a02.addActionListener(this);
a03.addActionListener(this);
a04.addActionListener(this);
a05.addActionListener(this);
a06.addActionListener(this);
a07.addActionListener(this);
a08.addActionListener(this);
a09.addActionListener(this);
a10.addActionListener(this);
c01.addActionListener(this);
c02.addActionListener(this);
c03.addActionListener(this);
c04.addActionListener(this);
c05.addActionListener(this);
c06.addActionListener(this);
c07.addActionListener(this);
c08.addActionListener(this);
c09.addActionListener(this);
c10.addActionListener(this);
c11.addActionListener(this);
c12.addActionListener(this);
AmtPpl.setSelectedIndex(3);
AmtPpl.addActionListener(this);
setLayout(new BorderLayout(20,10));
add(jlabel, BorderLayout.NORTH);
add(p1, BorderLayout.CENTER);
add(p2, BorderLayout.EAST);
}
public static void main(String[] args) {
MainClass frame = new MainClass();
frame.setTitle("Table Reservation System");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(550, 300);
frame.setVisible(true);
}
public void actionPerformed(ActionEvent e) {
JPanel InputPanel = new JPanel();
InputPanel.setLayout(new GridLayout(7,2));
InputPanel.add(FstName);
InputPanel.add(FName);
InputPanel.add(LstName);
InputPanel.add(LName);
InputPanel.add(Addrss);
InputPanel.add(Addr);
InputPanel.add(PstlCode);
InputPanel.add(PCode);
InputPanel.add(HndPne);
InputPanel.add(HP);
InputPanel.add(AoP);
InputPanel.add(AmtPpl);
InputPanel.add(Mndtry);
if(e.getSource()==a01) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==a02) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==a03) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==a04) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==a05) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==a06) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==a07) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==a08) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==a09) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==a10) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c01) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c02) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c03) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c04) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c05) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c06) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c07) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c08) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c09) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c10) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c11) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
else if(e.getSource()==c12) {
JOptionPane.showConfirmDialog(null, InputPanel, "Please enter the required information", JOptionPane.OK_CANCEL_OPTION);
}
}
}
提前致谢! (:
附注如果您有关于如何清理代码的提示，请分享!谢谢!顺便说一句，这是餐 table 预订系统的一些简单编码。虽然不完整。很快就会实现 MySQL 服务器和后端。
最佳答案
问题出现在这里
AmtPpl.addActionListener(this);
基本上，当它执行时，它会构建另一个对话框并显示。所以是的，该值正在更改，但因为您正在显示另一个对话框，所以它会覆盖它。
关于java - JComboBox 只能使用一次并且不会更新，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11770271/