如何在 Java 中创建多个表单？

Question

When I start my program, it loads the main form with buttons that does it's necessary functions. I'd like to know how to create a button that, once clicked, will open another form with it's own buttons and functions.

For example:

Main Form has the buttons: 'Log In', 'Quit'

I would like to create another form when you click on the 'Log In' button...

And yes, I know I can use String username = JOptionPane.showInputDialog("Input Username"); for it, but I would like to create my own Log In form.

Any help would be much appreciated...

Answer 1

First, write the following LogInForm class.

  import java.awt.FlowLayout;
    import javax.swing.JButton;
    import javax.swing.JPanel;
    import javax.swing.JTextField;

    public class LogInForm extends JPanel
    {
        JTextField username, password;
        JButton login;

        public LogInForm()
        {
            this.setLayout(new FlowLayout());

            username = new JTextField("Username");
            this.add(username);

            password = new JTextField("Password");
            this.add(password);

            login = new JButton("log in");
            this.add(login);
        }
    }

Then write the following class to do the job.

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

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

public class MainForm extends JPanel
{
    private JButton quit, logIn;
    public MainForm()
    {
        this.setLayout(new FlowLayout());

        quit = new JButton("quit");
        this.add(quit);

        logIn = new JButton("login");
        this.add(logIn);

        ActionHandler handler = new ActionHandler();
        logIn.addActionListener(handler);
    }

    private class ActionHandler implements ActionListener
    {
        public void actionPerformed(ActionEvent event) 
        {
            if(event.getSource() == logIn)
            {
                JFrame logInFrame = new JFrame();
                LogInForm logInForm = new LogInForm();
                logInFrame.getContentPane().add(logInForm);
                logInFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                logInFrame.setSize(400,300);
                logInFrame.setVisible(true);
            }
        }

    }

    public static void main(String[] args)
    {
        JFrame mainFrame = new JFrame();
        MainForm panel = new MainForm();
        mainFrame.getContentPane().add(panel);
        mainFrame.setSize(300,200);
        mainFrame.setVisible(true);

    }
}