[NUI] Add ChangeLayoutChildOrder to LayoutGroup

ChangeLayoutChildOrder is added to LayoutGroup to change the order of the child
layout in the layout group.

This PR has been made to resolve the following issue.
https://github.sec.samsung.net/dotnet/NUIBackend/issues/87

diff --git a/src/Tizen.NUI/src/public/Layouting/LayoutGroup.cs b/src/Tizen.NUI/src/public/Layouting/LayoutGroup.cs
index 9ec42de..adc9d2d 100755 (executable)
--- a/src/Tizen.NUI/src/public/Layouting/LayoutGroup.cs
+++ b/src/Tizen.NUI/src/public/Layouting/LayoutGroup.cs
@@ -165,6 +165,22 @@ namespace Tizen.NUI
             RequestLayout();
         }
 
+        /// <summary>
+        /// Sets the order of the child layout in the layout group.
+        /// </summary>
+        /// <param name="child">the child layout in the layout group</param>
+        /// <param name="order">the order of the child layout in the layout group</param>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public void ChangeLayoutChildOrder(LayoutItem child, int order)
+        {
+            if ((child != null) && (LayoutChildren.Count > order))
+            {
+                LayoutChildren.Remove(child);
+                LayoutChildren.Insert(order, child);
+                RequestLayout();
+            }
+        }
+
         // Attaches to View ChildAdded signal so called when a View is added to a view.
         private void AddChildToLayoutGroup(View child)
         {