Redrawing a new JFrame in an existing one?

Question

I'm trying to display a different JFrame after the user does something in the same window they are using, similar to a login feature. Haven't been able to figure out how to do that.

The workaround I have now is to just hide the current JFrame and then open a new one, which simulates a similar effect. But ideally I want it to just display the next JFrame in the same existing window.

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.JLabel;
import javax.swing.JTextField;

public class Login extends JFrame {
    private static int x = 0;
    static JTextField txtInput = new JTextField(10);
    static JButton btnSwitch = new JButton("Log on");

    public Login(){
        setLayout(new FlowLayout());

        //add button and register
        add(new JLabel("Enter password:"));
        add(txtInput);
        add(btnSwitch);
    }

    public static void main(String[] args) {
        final JFrame frame = new Login();

        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(200, 150);
        frame.setVisible(true);


        btnSwitch.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if(txtInput.getText().equals("123")){
                    //frame = new GUIHelloWorld(); this doesn't work because "The final local variable frame cannot be assigned, since it is defined in an enclosing type"
                    //so I went with the below workaround
                    GUIHelloWorld frame = new GUIHelloWorld();

                    frame.setLocationRelativeTo(null); // Center the frame
                    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    frame.setSize(300, 100);
                    frame.setVisible(true);
                }
            }
        });
    }
}

Once the user get pass the first part of the GUI, I want to show em something else like this:

import java.awt.GridLayout;

import javax.swing.JFrame;
import javax.swing.JLabel;

public class GUIHelloWorld extends JFrame {
    public GUIHelloWorld(){
        setLayout(new GridLayout(0,1));

        add(new JLabel("Hello World"));
        add(new JLabel("Welcome to the 2nd part of the GUI"));
    }

    public static void main(String[] args) {
        JFrame frame = new GUIHelloWorld();
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 100);
        frame.setVisible(true);
    }

}

Can someone give me an idea of how to display a new JFrame into the existing window that the user is using?

Answer 1

1. Don't extend from JFrame, especially in the case, frame's can't be added to other frames. Instead, based you individual UI views on something like JPanel
2. Create a single instance of a JFrame, set it's layout manager to use a CardLayout.
3. Add each of your view's to the frame, naming each view appropriately
4. Use CardLayout to switch between the view as needed

You could also consider using a JDialog for the login window, but the basic advice remains; create windows, extend components...