Is it normal to have all java swing gui in one class?

Question

I am just starting out with swing development and am having an issue. Is it normal to put the entire GUI into a single class? The application that I am building has one single JFrame that displays multiple different "pages". For example if the user clicks on a button they are taken to an entirely different page with a different layout. I've configured a Card Layout, and the one card that I have build so far uses the GridBag layout.

The question that I have, then, is
1. whether or not each page should have its own class?
2. If they do how do I communicate between the GUI controller which runs the card layout and the individual pages?
3. Or should I just put all of the GUI into the GUI controller and let it run like that.

Below is the code for what I have so far, I am new to this and really would like to get good at it so if you spot any major issues that I missed please feel free to point them out.

Code for the individual page:

public class HomePage extends JPanel implements ActionListener{
    private GridBagLayout gl;
    private JPanel frm;
    JButton newPersonalContact;
    HomePage(){
         frm=new JPanel();
         gl=new GridBagLayout();
         GridBagConstraints gbc=new GridBagConstraints();
         frm.setLayout(gl);

         newPersonalContact=new JButton("New Personal Contact");
         JButton newBusinessContact=new JButton("New Business Contact");
         JButton showAllContacts=new JButton("Show All Contacts");
         JButton saveAndQuit=new JButton("Save and Quit");

         JPanel top=new JPanel();
         top.setBackground(new Color(218,165,32));
         top.add(new JLabel("Western Governers University Presents:"));


         JPanel middle=new JPanel();
         middle.setBackground(new Color(43,37,85));
         GridLayout ge=new GridLayout(4,4);
         middle.setLayout(ge);

         middle.add(new JLabel(""));
         middle.add(new JLabel(""));
         middle.add(new JLabel(""));
         middle.add(new JLabel(""));
         middle.add(new JLabel(""));
         middle.add(newPersonalContact);


         middle.add(newBusinessContact);
         middle.add(new JLabel(""));
         middle.add(new JLabel(""));
         middle.add(showAllContacts);

         middle.add(saveAndQuit);
         middle.add(new JLabel(""));middle.add(new JLabel(""));
         middle.add(new  JLabel(""));
         middle.add(new JLabel(""));

         JPanel bottom=new JPanel();
         bottom.setBackground(new Color(218,165,32));

         gbc.fill=GridBagConstraints.BOTH;
         gbc.weightx=1.0;

         gbc.weighty=2.0;
         gbc.gridx=0;
         gbc.gridy=0;
         frm.add(top,gbc);

         gbc.weighty=6.0;
         gbc.gridx=0;
         gbc.gridy=1;
         frm.add(middle,gbc);

         gbc.weighty=1.0;
         gbc.gridx=0;
         gbc.gridy=2;
         frm.add(bottom,gbc);

         newPersonalContact.addActionListener(this);
         newBusinessContact.addActionListener(this);
         showAllContacts.addActionListener(this);
         saveAndQuit.addActionListener(this);


}
    public void actionPerformed(ActionEvent ae){
    if (ae.getSource()==newPersonalContact){
        //What goes here?
    }

}
public JPanel getFrame(){
    return frm;
}

}

code for the GUI controller:

public class GUIController {
    JFrame frm;
    CardLayout cl;
    Container pane;
GUIController(){
frm=new JFrame();
frm.setSize(800,600);
frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JPanel card2=new JPanel();
card2.setBackground(Color.black);

JPanel cards=new JPanel(new CardLayout());
cards.add(new HomePage().getFrame(), "Home");
cards.add(card2,"New Personal Contact");
pane=frm.getContentPane();
pane.add(cards,BorderLayout.CENTER);





}
public void start(){
    this.frm.setVisible(true);

}
public void showCard(){
    cl.show(pane, "Card2");
}


}

While this is for a school Project, the GUI interface is not required just something I am interested in learning. Thanks for any help.

Answer 1

No, I don't recommend to put all GUI code in class - at least if it gets big and does several things.

In that case use the Mediator pattern:

• put subcomponents to custom subclasses of JPanel
• that subclass listens for events of its children and updates other children
• fires own custom events if needed

Also note: If you're about to learn GUI programming and don't have a specific requirement to use Swing, consider to use the newer GUI toolkit JavaFX.