feat(UI): Add canvas show/hide hooks

Author: jcs090218

Assets/JCSUnity/Scripts/UI/JCS_Canvas.cs

@@ -6,6 +6,7 @@
  * $Notice: See LICENSE.txt for modification and distribution information
  *                   Copyright (c) 2016 by Shen, Jen-Chieh $
  */
+using System;
 using UnityEngine;
 using MyBox;
 
@@ -24,6 +25,9 @@ public class JCS_Canvas : MonoBehaviour
 
         private const string RESIZE_UI_PATH = "UI/ResizeUI";
 
+        public Action<JCS_Canvas> onShow = null;  // Execution when canvas is shown.
+        public Action<JCS_Canvas> onHide = null;  // Execution when canvas is hidden.
+
         private Canvas mCanvas = null;
 
         private RectTransform mAppRect = null;  // Application Rect (Window)
@@ -165,6 +169,8 @@ public void Show(bool mute = false)
             mCanvas.enabled = true;
             if (!mute)
                 JCS_SoundPlayer.PlayByAttachment(mDeactiveSound, JCS_SoundMethod.PLAY_SOUND);
+
+            onShow?.Invoke(this);
         }
 
         /// <summary>
@@ -175,6 +181,8 @@ public void Hide(bool mute = false)
             mCanvas.enabled = false;
             if (!mute)
                 JCS_SoundPlayer.PlayByAttachment(mActiveSound, JCS_SoundMethod.PLAY_SOUND);
+
+            onHide?.Invoke(this);
         }
 
         /// <summary>
@@ -199,7 +207,7 @@ private void CheckMainCanvas()
 
             if (main != null)
             {
-                JCS_Debug.LogWarning("Having multiple main canvases is often not allowed, " + this.gameObject.name);
+                JCS_Debug.LogWarning("Having multiple main canvases is often not allowed: " + this.gameObject.name);
                 return;
             }
 

docs/ScriptReference/UI/JCS_Canvas.md

@@ -6,6 +6,8 @@ Control of the canvas component.
 
 | Name            | Description                                      |
 |:----------------|:-------------------------------------------------|
+| onShow          | Execution when canvas is shown.                  |
+| onHide          | Execution when canvas is hidden.                 |
 | mDisplayOnAwake | If true, show on awake time; otherwise, hide it. |
 | mMainCanvas     | Resizable screen will be attach to this canvas.  |
 | mActiveSound    | Play sound when active the canvas.               |