GUI multiple frames switch

Question

I am writing a program for a black jack game. It is an assignment we are not to use gui\'s but I am doing it for extra credit I have created two frames ant they are working.

Answer 1

Since I had to test it myself if it is in fact so easy to implement, I built this simple example. It demonstrates a solution to your problem. Slightly inspired by @jzd's answer (+1 for that).

import java.awt.Color;
import java.awt.HeadlessException;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class FocusChangeTwoFrames
{
    public static void main(String[] args)
    {
        SwingUtilities.invokeLater(new Runnable() 
        {
            @Override
            public void run()
            {   
                createGUI();
            }
        });
    }

    private static void createGUI() throws HeadlessException
    {
        final JFrame f2 = new JFrame();
        f2.getContentPane().setBackground(Color.GREEN);     
        final JFrame f1 = new JFrame();     
        f1.getContentPane().setBackground(Color.RED);
        f1.setSize(400, 300);
        f1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f1.setVisible(true);
        MouseListener ml = new MouseAdapter()
        {
            @Override
            public void mousePressed(MouseEvent e)
            {
                if(f1.hasFocus())
                    f2.requestFocus();
                else
                    f1.requestFocus();
            }
        };
        f1.addMouseListener(ml);
        f2.setSize(400, 300);
        f2.setLocation(200, 150);
        f2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f2.setVisible(true);
        f2.addMouseListener(ml);
    }
}

Enjoy, Boro.

Answer 2

A couple of suggestions:

You're adding components to a JPanel that uses FlowLayout but are using BorderLayout constants when doing this which you shouldn't do as it doesn't make sense:

  add(play, BorderLayout.CENTER);

Rather, if using FlowLayout, just add the components without those constants.

Also, rather than swap JFrames, you might want to consider using a CardLayout and swapping veiws in a single JFrame. For instance:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class FooBarBazDriver {
   private static final String INTRO = "intro";
   private static final String GAME = "game";
   private CardLayout cardlayout = new CardLayout();
   private JPanel mainPanel = new JPanel(cardlayout);
   private IntroPanel introPanel = new IntroPanel();
   private GamePanel gamePanel = new GamePanel();

   public FooBarBazDriver() {
      mainPanel.add(introPanel.getMainComponent(), INTRO);
      mainPanel.add(gamePanel.getMainComponent(), GAME);

      introPanel.addBazBtnActionListener(new ActionListener() {
         @Override
         public void actionPerformed(ActionEvent e) {
            cardlayout.show(mainPanel, GAME);
         }
      });

      gamePanel.addBackBtnActionListener(new ActionListener() {
         @Override
         public void actionPerformed(ActionEvent e) {
            cardlayout.show(mainPanel, INTRO);
         }
      });
   }

   private JComponent getMainComponent() {
      return mainPanel;
   }

   private static void createAndShowUI() {
      JFrame frame = new JFrame("Foo Bar Baz");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(new FooBarBazDriver().getMainComponent());
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      java.awt.EventQueue.invokeLater(new Runnable() {
         public void run() {
            createAndShowUI();
         }
      });
   }
}

class IntroPanel {
   private JPanel mainPanel = new JPanel();
   private JButton baz = new JButton("Baz");
   private JButton exit = new JButton("Exit");

   public IntroPanel() {
      mainPanel.setLayout(new FlowLayout());
      baz = new JButton("Start");
      exit = new JButton("exit");

      mainPanel.add(new JLabel("Hello World"));
      mainPanel.add(baz);
      mainPanel.add(exit);

      exit.addActionListener(new ActionListener() {
         @Override
         public void actionPerformed(ActionEvent e) {
            Window win = SwingUtilities.getWindowAncestor(mainPanel);
            win.dispose();
         }
      });
   }

   public void addBazBtnActionListener(ActionListener listener) {
      baz.addActionListener(listener);
   }

   public JComponent getMainComponent() {
      return mainPanel;
   }

}

class GamePanel {
   private static final Dimension MAIN_SIZE = new Dimension(400, 200);
   private JPanel mainPanel = new JPanel();

   private JButton foo;
   private JButton bar;
   private JButton back;

   public GamePanel() {
      foo = new JButton("Foo");
      bar = new JButton("Bar");
      back = new JButton("return to main menu");

      mainPanel.add(foo);
      mainPanel.add(bar);
      mainPanel.add(back);
      mainPanel.setPreferredSize(MAIN_SIZE);
   }

   public JComponent getMainComponent() {
      return mainPanel;
   }

   public void addBackBtnActionListener(ActionListener listener) {
      back.addActionListener(listener);
   }

}

Answer 3

The second frame needs a reference to the first frame so that it can set the focus back to the first frame.

Also your classes extend JFrame but they are also creating other frames in their constructors.