Friday Treat - GUI Menu System (C#)

I've read and taken some scripts here and there so I thought that since I'm in a good mood today, I'd give something back. The behavior below is a real simple menu system for Unity (I use it for my iPhone project).

The system is based around delegates in C#. Simply put, I have a single delegate defined which gets called by my OnGUI method. By simply assigning different methods to that delegate, I can easily switch menus on the fly without any if statements, loading new levels or whatever else people do.

Code (csharp):

1. private delegate void GUIMethod();
2. private GUIMethod currentGUIMethod;

You can see where I first define the delegate. Any methods that you define must therefore match that signature. I then create a member variable of that delegate type. My OnGUI method is simply:

Code (csharp):

1. public void OnGUI ()
2. {
3.     this.currentGUIMethod();
4. }

Here's the full code. Note that I don't have all the pieces in but those missing pieces are not essential to this.

Code (csharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class MainMenu : MonoBehaviour
5. {
6.     public GUISkin guiSkin;
7.  
8.     private delegate void GUIMethod();
9.     private GUIMethod currentGUIMethod;
10.    
11.     // Use this for initialization
12.     void Start ()
13.     {
14.         this.currentGUIMethod = MainMenuGUI;
15.     }
16.    
17.     public void MainMenuGUI()
18.     {
19.         GUI.skin = this.guiSkin;
20.        
21.         GUI.BeginGroup (new Rect (80, 70, Screen.width - 200, Screen.height - 80));
22.         {
23.             GUI.Box (new Rect (0,0,Screen.width - 200,Screen.height - 80), "SuperBall Factory", GUI.skin.GetStyle("box"));
24.            
25.             // First button
26.             if (GUI.Button (new Rect (10,25,Screen.width - 220,40), "New Story", GUI.skin.GetStyle("button")))
27.             {
28.                 Application.LoadLevel ("Sort");
29.             }
30.            
31.             if (GUI.Button (new Rect (10,75,Screen.width - 220,40), "Free Play", GUI.skin.GetStyle("button")))
32.             {
33.                 // go to next menu
34.                 this.currentGUIMethod = FreeplayMenuGUI;
35.             }            
36.         }
37.         GUI.EndGroup();
38.     }
39.    
40.     public void FreeplayMenuGUI()
41.     {
42.         GUI.skin = this.guiSkin;
43.        
44.         GUI.BeginGroup (new Rect (80, 70, Screen.width - 200, Screen.height - 80));
45.         {
46.         GUI.Box (new Rect (0,0,Screen.width - 200,Screen.height - 80), "SuperBall Factory", GUI.skin.GetStyle("box"));
47.            
48.             if (GUI.Button (new Rect (10,25,Screen.width - 220,40), "Superball Sorter", GUI.skin.GetStyle("button")))
49.             {
50.                 Application.LoadLevel ("Sort");
51.             }
52.            
53.             if (GUI.Button (new Rect (10,75,Screen.width - 220,40), "Superball Saver", GUI.skin.GetStyle("button")))
54.             {
55.                 Application.LoadLevel ("Deflect");
56.             }
57.            
58.             if (GUI.Button (new Rect (10,125,Screen.width - 220,40), "Superball Catcher", GUI.skin.GetStyle("button")))
59.             {
60.                 Application.LoadLevel ("CatchBox");
61.             }
62.         }
63.         GUI.EndGroup();
64.     }
65.    
66.     // Update is called once per frame
67.     public void OnGUI ()
68.     {
69.         this.currentGUIMethod();
70.     }
71. }
72.  

If anyone thinks this is wiki worthy, I'll throw it up there (haven't checked to see if there is anything else similar.

 

I should also note, this is a pretty game specific menu (my game that is) behavior. It really should be made more generic. I just wanted to demonstrate the delegate behavior.

I also have another system that I'll post soon but its much more complicated. It consists of instantiating dynamic C# objects based on a text file coupled with a sequential set of something I've been calling Actions thereby doing something like a script language within a script language.

 

Thanks for that , very helpful indeed.

 

Definately put it up on the wiki with some simple instructions as to what gameobject to add the script to, etc. This way it doesn't disappear into the anals of thread history like so many things do.

 

Ok, I went ahead and posted it to the wiki. Made it more tutorial like in order to explain it better.

http://www.unifycommunity.com/wiki/index.php?title=MainMenu

 

Awesome job and I know people will truely appreciate it.

 

This is an excellent use of delegates. Exactly what they were designed for!

 

Nice way to handle the UI. Need to get rid of the 1000 bool variables and the if-else conditions I now have in my game.

 

Very nice implementation, thank you for sharing

 

Old post but very nice explanation. Thanks a lot !