我无法通过输入和用户输入另一个 class

Question

I am having a problem getting variables from one class to another (passEntered and userEntered) the are giving errors every time I set them up. I have tried getters and setters but it doesn't seem to work. The variables are getting inputs but don't seem to want to share to other classes.

First Class:

public class LoginGUI {
    private JFrame frame = new JFrame ();
    private JPanel panel = new JPanel();
    private JLabel passwordLabel = new JLabel ("Enter Your Password:");
    private JButton loginButton = new JButton ("Login");
    **JTextArea usernameEnter = new JTextArea (0, 0);**
    private JLabel usernameLabel = new JLabel ("Enter Your Username:");
    **JPasswordField passwordEnter = new JPasswordField (5);**
    private JLabel registerLabel = new JLabel ("If you dont have an account register here:");
    private JButton registerButton = new JButton ("Register");
    **public String userEntered;
    public String passEntered;**

    public LoginGUI() {
        PanelSetup();
        FrameSetup();
        setBounds();

        loginButton.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                **userEntered = usernameEnter.getText();
                passEntered = passwordEnter.getText();**
                System.out.println(passEntered);
                System.out.println(userEntered);

            }

        });

        registerButton.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                if(e.getSource()==registerButton){
                    frame.dispose();
                    registerGUI myWindow = new registerGUI();
                }
            }
        });

    }

Second Class:

public class loginChecker {
String username, password;

    
    public static void main (String[] args) {
        new loginChecker();
    }

    private void loginChecker() {
        setUsername();
        setPassword();
    }

    private void setPassword() {
        password = passEntered;
    }

    private void setUsername() {
        username = userEntered;
    }

}

If you could help it would be greatly appreciated

Answer 1

The class loginChecker should start with an uppercase letter, as the naming conventions suggest. Other than that, how should the class know the passEntered and userEntered variables? I would change the class like so:

public class LoginChecker {
    public String username, password;
    public void changePassword(String newPassword) {
        // TODO: Check whether the password matches some criteria
        // TODO: Encrypt password
        password=newPassword;
    }
    public void changeUsername(String newUsername) {
        // TODO: Check Username availability
        username = newUsername;
    }
    public String getUsername() { return username; }
    // Could also change the signature to use a key String that will be used to decrypt an encrypted password
    public String getPassword() { return password; }
}

Also, you should probably not store passwords unencrypted.
Inside the LoginGUI class, you save a reference to a LoginChecker object and use its fields.

...
LoginChecker loginChecker = new LoginChecker();
...
loginChecker.changeUsername(usernameEnter.getText());
loginChecker.changePassword(passwordEnter.getText());
// You can then get the password and username using loginChecker.getUsername() and loginChecker.getPassword()