fix(Util): Over GUI on mobile

Author: jcs090218

Assets/JCSUnity/Scripts/Util/JCS_UIUtil.cs

@@ -888,13 +888,17 @@ public static bool MouseOverGUI(RectTransform imageRect, RectTransform rootPanel
         /// </returns>
         public static bool IsOverGUI()
         {
+            return IsOverGUI(0);
+        }
+        public static bool IsOverGUI(int index)
+        {
 #if (UNITY_EDITOR || UNITY_STANDALONE || UNITY_WEBGL)
             return EventSystem.current.IsPointerOverGameObject();
 #elif (UNITY_ANDROID || UNITY_IPHIONE || UNITY_IOS)
-            if (Input.touchCount <= 0)
+            if (Input.touchCount <= index)
                 return false;
 
-            Touch touch = Input.GetTouch(0);
+            Touch touch = Input.GetTouch(index);
 
             return EventSystem.current.IsPointerOverGameObject(touch.fingerId);
 #else