Working with multiple JComponents

**hvince95** · 01-23-2012, 12:08 AM

Hello, I have been making a game and it works great! I have now been trying to implement a menu by putting the main game in a JComponent, and the menu in a seperate JComponent. In a main class I add them both to the JFrame and do a little test to make only the enabled one visible. It doesnt really work. Please help! Oasis is one JComponent, MainMenu is another (both extend JComponent).

Java Code:

public class Main extends JFrame implements GameConfig{
	
	private Oasis gamePanel = new Oasis();
	private MainMenu menuPanel = new MainMenu();
	private String gamePhase = "runGame";
	
	public Main() {

		this.setTitle("Oasis");
		this.setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
		this.setLocationRelativeTo(null);
		this.setResizable(false);
		this.setVisible(true);
		
		addWindowListener(new WindowAdapter() {
			@Override
			public void windowClosing(WindowEvent e) {
				setVisible(false); // hide the window quickly
				dispose(); // release all system resources
				System.exit(0); // finally exit.
			}
		});
		
		add(gamePanel);
		add(menuPanel);
		if (gamePhase.equals("runGame")) {
			menuPanel.setVisible(false);
			menuPanel.setEnabled(false);
			gamePanel.setVisible(true);
			gamePanel.setEnabled(true);
		}
		if (gamePhase.equals("mainMenu")) {
			gamePanel.setVisible(false);
			gamePanel.setEnabled(false);
			menuPanel.setVisible(true);
			menuPanel.setEnabled(true);
		}
	}
	
	public static void main(String[] args) {
		@SuppressWarnings("unused")
		Main gameFrame = new Main();
	}
}

But it only shows a white/ish screen and not the game component. (It should definately draw something because if I only add the game component it works perfectly, but without a menu!)
Thankyou very much.

**Fubarable** · 01-23-2012, 12:18 AM

Don't try to fiddle with this yourself when the CardLayout was made just for this situation. So have the contentPane use this layout and swap views when necessary.

**pbrockway2** · 01-23-2012, 12:20 AM

Java Code:

add(gamePanel);
add(menuPanel);

You add these panels to the frame's content pane which has a border layout. The effect is that menuPanel will replace gamePanel since both can't occupy the center of the content pane.

You could set a different layout manager on the frame's content pane. Or, better I think, create a panel to hold the gamePanel and menuPanel and give this other panel an appropriate layout manager (CardLayout?). Then set this other panel as the content pane of your frame.

See Using toplevel Containers and Laying out Components within a Container in Oracle's Tutorial.

-----

This is a Swing question do I'll move it to the Awt/Swing forum.

**hvince95** · 01-23-2012, 12:24 AM

Thankyou for your quick answers and moving the thread, I'll have to check out how to use CardLayout!

**hvince95** · 01-23-2012, 01:11 AM

so that works like a treat (Thankyou so much!)
But there is one problem, I cannot access the CardLayout JPanel object from within the two components that it is holding to be able to change which one is being shown.
If that is a bit confusing, in the Main class, I create the JPanel with cardlayout layout. I create two custom JComponent classes (extends jcomponent), and it is within them that I need to be able to access the JPanel within the main class.
How do you think I should do this?

**Fubarable** · 01-23-2012, 02:09 AM

You could pass a reference from one class into the other. For instance, you could give the top level GUI a public class that allows other classes to swap views, say something like

Java Code:

public void swapView(String name) {

    // cardLayout is a class field that refers to the CardLayout
    // cardContainer is a class field that refers to the container that uses CardLayout
    cardLayout.show(cardContainer, name);

}

You could also give this class public static void String constants that hold the name Strings.

Then pass a reference of the top level gui class to the subclasses so that they can call this method when necessary.

**hvince95** · 01-23-2012, 02:16 AM

Originally Posted by Fubarable

You could pass a reference from one class into the other. For instance, you could give the top level GUI a public class that allows other classes to swap views

What do you mean by this? put another class within the main class? I dont understand. please help!

**Fubarable** · 01-23-2012, 02:25 AM

Originally Posted by hvince95

What do you mean by this? put another class within the main class? I dont understand. please help!

You're already doing this as your main class will of necessity hold other objects, Oasis and MainMenu. If you want to allow objects of these classes to call methods of the main object, you'll need to pass a reference from the main into them, likely through a constructor parameter:

Java Code:

	
public class Main extends JFrame implements GameConfig{
     
    private Oasis gamePanel = new Oasis(this);
    private MainMenu menuPanel = new MainMenu(this);
    private String gamePhase = "runGame";

Java Code:

public class Oasis {
   private Main main;

   public Oasis (Main main) {
      this.main = main;
      
      // ... plus other code for the constructor.
   }

   // then in an ActionListener for some JButton or menu, you'll call 
   // main.swapView(Main.OTHER_PANEL);

}