在動作監聽器中啟用Jbutton

Question

我遇到了一個問題。我用3個按鈕在Java中創建了一個注冊表單.LogIn，SignUp和Place order我有setEnabled（False）。在用戶提供后，我想在由id和psw組成的loginframe中具有正確ID和psw的系統，必須啟用PlaceOrder按鈕。如何管理？

主機類

 public class MainFrame extends JFrame{

        private JButton loginButton;
        private JButton signUpButton;
         JButton placeOrderButton;

        private boolean q;

        private UserManager userManager;

        public MainFrame(){
            super("Main Panel");
            userManager = new UserManager();
            loginButton = new JButton("Login");
            loginButton.addActionListener(new LoginButtonListener());
            placeOrderButton = new JButton("Place Order");
            placeOrderButton.addActionListener(new PlaceOrderButtonListener());
            placeOrderButton.setEnabled(false);



            signUpButton = new JButton("Sign Up");
            signUpButton.addActionListener(new SignUpButtonListener());



            this.getContentPane().add(loginButton, BorderLayout.LINE_START);
            this.getContentPane().add(signUpButton, BorderLayout.CENTER);
            this.getContentPane().add(placeOrderButton, BorderLayout.LINE_END);
            this.pack();
            this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            this.setVisible(true);






        }

        class LoginButtonListener implements ActionListener{

            @Override

            public void actionPerformed(ActionEvent arg0) {
                 new LoginFrame(userManager);

            }
        }

        class SignUpButtonListener implements ActionListener{

            @Override
            public void actionPerformed(ActionEvent arg0) {
                new SignUpFrame(userManager);
            }
        }


        class PlaceOrderButtonListener implements ActionListener {

            public void actionPerformed(ActionEvent argO){



            }


        }

LoginFrame類

public class LoginFrame extends JFrame{

    private JButton loginButton;
    private JTextField usernameField;
    private JPasswordField password;

    private UserManager userManager;

    public LoginFrame(UserManager userManager){
        super("Enter your credentials to login");
        this.userManager = userManager;
        loginButton = new JButton("Login");
        loginButton.addActionListener(new LoginButtonListener());

        usernameField = new JTextField(15);
        password = new JPasswordField(15);

        JPanel mainPanel = new JPanel();
        mainPanel.setLayout(new GridLayout(3,2));

        mainPanel.add(new JLabel("Username:"));
        mainPanel.add(usernameField);
        mainPanel.add(new JLabel("Password:"));
        mainPanel.add(password);
        mainPanel.add(loginButton);

        this.setContentPane(mainPanel);
        this.pack();
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
    }           
        class LoginButtonListener implements ActionListener{


public void actionPerformed(ActionEvent arg0) {
    String givenID = usernameField.getText();



    if(userManager.isUserInList(givenID)){
        String givenPass = password.getText();
        User theUser = userManager.getUserWithID(givenID);
        if(givenPass.equals(theUser.getPassword())){
            dispose();

            JOptionPane.showMessageDialog(null, "Access granted!");


        }


        else{
            JOptionPane.showMessageDialog(null, 
                            "Wrong Password", 
                            "Error!",
                            JOptionPane.ERROR_MESSAGE);
        }
    }
    else{
        JOptionPane.showMessageDialog(null, 
                "Wrong username", 
                "Error!",
                JOptionPane.ERROR_MESSAGE);
    }
}

}

類UserManager

import java.util.ArrayList;


public class UserManager {

    private ArrayList<User> userList;

    public UserManager(){
        userList = new ArrayList<User>();
        User u1 = new User("Teo Haik", "teo@uom.gr","teohaik","teopass");
        userList.add(u1);
    }

    public boolean isUserInList(String ID){
        for(User u: userList){
            if(u.getUserID().equals(ID)){
                return true;
            }
        }
        return false;
    }

    public User getUserWithID(String ID){
        for(User u: userList){
            if(u.getUserID().equals(ID)){
                return u;
            }
        }
        return null;
    }

    public void addUser(User p){
        if(!userList.contains(p)){
            userList.add(p);
        }
    }
}

Answer 1

我無法理解您的代碼，下面是完整的可正常使用的代碼：希望對您有所幫助

用作指導

package stackoverflow;

import java.awt.EventQueue;

public class Login {

    private JFrame frame;
    private JTextField txtusername;
    private JPasswordField txtPassword;
    private JButton btnPlaceorder;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Login window = new Login();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public Login() {
        initialize();
    }

    /**
     * Initialize the contents of the frame.
     */
    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 341, 240);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        JLabel lblUsername = new JLabel("Username:");
        lblUsername.setBounds(21, 56, 52, 14);
        frame.getContentPane().add(lblUsername);

        JLabel lblPassword = new JLabel("Password");
        lblPassword.setBounds(21, 94, 52, 14);
        frame.getContentPane().add(lblPassword);

        txtusername = new JTextField();
        txtusername.setBounds(83, 53, 86, 20);
        frame.getContentPane().add(txtusername);
        txtusername.setColumns(10);

        txtPassword = new JPasswordField();
        txtPassword.setColumns(10);
        txtPassword.setBounds(83, 91, 86, 20);
        frame.getContentPane().add(txtPassword);

        JButton btnNewButton = new JButton("Login");
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (txtusername.getText().equals("admin") && new String(txtPassword.getPassword()).equals("admin")) {
                    btnPlaceorder.setEnabled(true);
                } else {
                    btnPlaceorder.setEnabled(false);
                }
            }
        });
        btnNewButton.setBounds(10, 138, 89, 23);
        frame.getContentPane().add(btnNewButton);

        btnPlaceorder = new JButton("PlaceOrder");
        btnPlaceorder.setEnabled(false);
        btnPlaceorder.setBounds(105, 138, 89, 23);
        frame.getContentPane().add(btnPlaceorder);
    }
}

Answer 2

這是現在可以正常工作的代碼：

我已經修復了，但是您的代碼編寫得不好。 我已經更新了一些內容，例如密碼檢查，只是為了進行測試。

主機類

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;

public class MainFrame extends JFrame {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private JButton loginButton;
    private JButton signUpButton;
    private JButton placeOrderButton;

    private boolean q;

    private UserManager userManager;
    private LoginFrame loginFrame;

    public MainFrame() {
        super("Main Panel");
        userManager = new UserManager();
        loginButton = new JButton("Login");
        loginButton.addActionListener(new LoginButtonListener());
        placeOrderButton = new JButton("Place Order");
        placeOrderButton.addActionListener(new PlaceOrderButtonListener());
        placeOrderButton.setEnabled(false);

        signUpButton = new JButton("Sign Up");
        signUpButton.addActionListener(new SignUpButtonListener());

        this.getContentPane().add(loginButton, BorderLayout.LINE_START);
        this.getContentPane().add(signUpButton, BorderLayout.CENTER);
        this.getContentPane().add(placeOrderButton, BorderLayout.LINE_END);
        this.pack();
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        loginFrame = new LoginFrame(this);
        this.setVisible(true);

    }

    public void enableOrder() {
        this.placeOrderButton.setEnabled(true);
    }

    class LoginButtonListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            loginFrame.init(userManager);

        }
    }

    class SignUpButtonListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            // new SignUpFrame(userManager);
        }
    }

    class PlaceOrderButtonListener implements ActionListener {

        public void actionPerformed(ActionEvent argO) {

        }

    }
}

登錄框架

import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

public class LoginFrame extends JFrame {

    private JButton loginButton;
    private JTextField usernameField;
    private JPasswordField password;

    private UserManager userManager;
    private MainFrame mainFrame;

    public LoginFrame(MainFrame mainFrame) {
        super("Enter your credentials to login");
        this.mainFrame = mainFrame;

    }

    public void init(UserManager userManager) {
        loginButton = new JButton("Login");
        loginButton.addActionListener(new LoginButtonListener());

        usernameField = new JTextField(15);
        password = new JPasswordField(15);

        JPanel mainPanel = new JPanel();
        mainPanel.setLayout(new GridLayout(3, 2));

        mainPanel.add(new JLabel("Username:"));
        mainPanel.add(usernameField);
        mainPanel.add(new JLabel("Password:"));
        mainPanel.add(password);
        mainPanel.add(loginButton);
        this.userManager = userManager;
        this.setContentPane(mainPanel);
        this.pack();
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
    }

    class LoginButtonListener implements ActionListener {

        public void actionPerformed(ActionEvent arg0) {
            String givenID = usernameField.getText();

            if (userManager.isUserInList(givenID)) {
                String givenPass = new String(password.getPassword());
                User theUser = userManager.getUserWithID(givenID);
                if (givenPass.equals("password")) {

                    dispose();

                    JOptionPane.showMessageDialog(null, "Access granted!");
                    mainFrame.enableOrder();

                }

                else {
                    JOptionPane.showMessageDialog(null, "Wrong Password", "Error!", JOptionPane.ERROR_MESSAGE);
                }
            } else {
                JOptionPane.showMessageDialog(null, "Wrong username", "Error!", JOptionPane.ERROR_MESSAGE);
            }
        }
    }

}