我正在创建一个“商店”程序，基本上可以让员工使用我提供的用户名和密码登录。登录后，员工可以看到一个带有四个按钮的“主菜单”：销售登记、PLU 设置、设置和注销。在此屏幕中，员工可以通过单击任何按钮导航到该屏幕来继续。我不希望每次单击按钮时都会弹出一个新窗口，而是希望有一些过渡（或没有过渡）以转到单击的页面。
举个例子：当员工启动程序时，他/她会看到登录菜单。然后员工输入他/她的登录信息并点击登录。如果信息不正确，则会提示员工重新输入信息。如果信息正确，员工现在被发送到主菜单。在主菜单，员工选择“销售登记”，程序进入销售登记。所有这些都应该发生在一个窗口中。
到目前为止，我已经添加了我能够做的代码。我已经创建了所有按钮和标签，但我无法让它们显示在 JFrame 上并使用 CardLayout。另外，我不知道如何将登录代码与 CardLayout 链接。
感谢你们对我的帮助。这是代码：
主菜单代码 (storeMainMenu.java)
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class storeMainMenu implements ActionListener {
String loginString = "Login";
String salesRegisterString = "Sales Register";
String pluSettingsString = "PLU Settings";
String settingsString = "Settings";
String logoutString = "Logout";
//JFrame
int width = Toolkit.getDefaultToolkit().getScreenSize().width;
int height = Toolkit.getDefaultToolkit().getScreenSize().height;
Color myColor = Color.decode("#F1E0B8");
//JPanel
static JPanel buttonPanel = new JPanel();
JPanel test1 = new JPanel();
JPanel test2 = new JPanel();
JPanel test3 = new JPanel();
JPanel test4 = new JPanel();
//Buttons
JButton salesRegister = new JButton("Sales Register");
JButton pluSettings = new JButton("PLU Settings");
JButton settings = new JButton("Settings");
JButton logout = new JButton("Logout");
//Label
JLabel header = new JLabel("Store Register");
JLabel test_1 = new JLabel("Test 1");
JLabel test_2 = new JLabel("Test 2");
JLabel test_3 = new JLabel("Test 3");
JLabel test_4 = new JLabel("Test 4");
public storeMainMenu ()
{
//Header
header.setFont(new Font("Myriad", Font.PLAIN, 50));
header.setBounds((width/6),0,1000,100);
//Sales Register Bounds
salesRegister.setBounds(100, 100, 500, 250);
//PluSettings Bounds
pluSettings.setBounds(700, 100, 500, 250);
//Settings Bounds
settings.setBounds(100, 500, 500, 250);
//Logout Bounds
logout.setBounds(700, 500, 500, 250);
//JPanel bounds
buttonPanel.setLayout(null);
//TEST JPANEL
test1.setLayout(null);
test2.setLayout(null);
test3.setLayout(null);
test4.setLayout(null);
test1.setSize(width, height);
test2.setSize(width,height);
test3.setSize(width, height);
test4.setSize(width, height);
//Test JPANEL Labels
test_1.setFont(new Font("Myriad", Font.PLAIN, 50));
test_1.setBounds((width/6),0,1000,100);
test_2.setFont(new Font("Myriad", Font.PLAIN, 50));
test_2.setBounds((width/6),0,1000,100);
test_3.setFont(new Font("Myriad", Font.PLAIN, 50));
test_3.setBounds((width/6),0,1000,100);
test_4.setFont(new Font("Myriad", Font.PLAIN, 50));
test_4.setBounds((width/6),0,1000,100);
//Adding to test JPanel
test1.add(test_1);
test2.add(test_2);
test3.add(test_3);
test4.add(test_4);
//Adding to JFrame
buttonPanel.add(header);
buttonPanel.add(salesRegister);
buttonPanel.add(pluSettings);
buttonPanel.add(settings);
buttonPanel.add(logout);
}
@Override
public void actionPerformed(ActionEvent e) {
CardLayout cardLayout = new CardLayout();
if (e.getSource() == salesRegister) {
cardLayout.show(test1, salesRegisterString);
}
if (e.getSource() == pluSettings) {
cardLayout.show(test2, pluSettingsString);
}
if (e.getSource() == settings) {
cardLayout.show(test3, settingsString);
}
if (e.getSource() == logout) {
cardLayout.show(test4, logoutString);
}
}
static void createAndShowGUI() {
int width = Toolkit.getDefaultToolkit().getScreenSize().width;
int height = Toolkit.getDefaultToolkit().getScreenSize().height;
Color myColor = Color.decode("#F1E0B8");
JFrame frame = new JFrame("Store");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
frame.setSize(width, height);
frame.setBackground(myColor);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.add(buttonPanel);
}
public static void main (String[] args)
{
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
createAndShowGUI();
}
});
}
}
登录代码（login.java）：
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
@SuppressWarnings("serial")
public class login extends JFrame {
//declaring our swing components
JLabel l_name,l_pass;
JTextField t_name;
JPasswordField t_pass; //A special JTextField but hides input text
JButton button;
Container c;
boolean checkLogin = false;
//a inner class to handling ActionEvents
handler handle;
//a separate class for processing database connection and authentication
database db;
login()
{
super("Login form");
c=getContentPane();
c.setLayout(new FlowLayout());
//extra classes
db=new database();
handle =new handler();
//swing components
l_name=new JLabel("Username");
l_pass=new JLabel("Password");
t_name=new JTextField(10);
t_pass=new JPasswordField(10);
button=new JButton("Login");
//adding actionlistener to the button
button.addActionListener(handle);
//add to contaienr
c.add(l_name);
c.add(t_name);
c.add(l_pass);
c.add(t_pass);
c.add(button);
//visual
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(200,175);
}
public static void main(String args[])
{
@SuppressWarnings("unused")
login sample=new login();
}
//an inner class .You can also write as a separate class
class handler implements ActionListener
{
//must implement method
//This is triggered whenever the user clicks the login button
public void actionPerformed(ActionEvent ae)
{
//checks if the button clicked
if(ae.getSource()==button)
{
char[] temp_pwd=t_pass.getPassword();
String pwd=null;
pwd=String.copyValueOf(temp_pwd);
System.out.println("Username,Pwd:"+t_name.getText()+","+pwd);
//The entered username and password are sent via "checkLogin()" which return boolean
if(db.checkLogin(t_name.getText(), pwd))
{
//a pop-up box
JOptionPane.showMessageDialog(null, "You have logged in successfully","Success",
JOptionPane.INFORMATION_MESSAGE);
checkLogin = true;
}
else
{
//a pop-up box
JOptionPane.showMessageDialog(null, "Login failed!","Failed!!",
JOptionPane.ERROR_MESSAGE);
checkLogin = false;
}
}//if
}//method
}//inner class
}
数据库代码（登录代码引用此代码获取 MySQL 信息）（database.java）
import java.sql.*;
public class database
{
Connection con;
PreparedStatement pst;
ResultSet rs;
database()
{
try{
//MAKE SURE YOU KEEP THE mysql_connector.jar file in java/lib folder
//ALSO SET THE CLASSPATH
Class.forName("com.mysql.jdbc.Driver");
con=DriverManager.getConnection("jdbc:mysql://localhost:3306/SchoolStoreUsers","root","schoolstore");
pst=con.prepareStatement("select * from users where uname=? and pwd=?");
}
catch (Exception e)
{
System.out.println(e);
}
}
//ip:username,password
//return boolean
public Boolean checkLogin(String uname,String pwd)
{
try {
pst.setString(1, uname); //this replaces the 1st "?" in the query for username
pst.setString(2, pwd); //this replaces the 2st "?" in the query for password
//executes the prepared statement
rs=pst.executeQuery();
if(rs.next())
{
//TRUE iff the query founds any corresponding data
return true;
}
else
{
return false;
}
} catch (Exception e) {
// TODO Auto-generated catch block
System.out.println("error while validating"+e);
return false;
}
}
}
