[NUI] Fix FlexLayout to measure its child correctly

FlexLayout calculated child view's size in OnLayout() without
considering child layout's measured size unlike other layouts'
OnLayout().

This caused that the grand child view's size was calculated incorrectly
if the child and grand child had MatchParent Width/HeightSpecification.

To resolve this issue, child layout's measured size is set with the
child view's size calculated by dali-toolkit's YOGA APIs.

diff --git a/src/Tizen.NUI/src/public/Layouting/FlexLayout.cs b/src/Tizen.NUI/src/public/Layouting/FlexLayout.cs
index 2b37319..be9e542 100755 (executable)
--- a/src/Tizen.NUI/src/public/Layouting/FlexLayout.cs
+++ b/src/Tizen.NUI/src/public/Layouting/FlexLayout.cs
@@ -811,7 +811,19 @@ namespace Tizen.NUI
                 {
                     // Get the frame for the child, start, top, end, bottom.
                     Vector4 frame = new Vector4(Interop.FlexLayout.GetNodeFrame(swigCPtr, childIndex), true);
-                    childLayout?.Layout(new LayoutLength(frame.X), new LayoutLength(frame.Y), new LayoutLength(frame.Z), new LayoutLength(frame.W));
+
+                    // Child view's size is calculated in OnLayout() without considering child layout's measured size unlike other layouts' OnLayout().
+                    // This causes that the grand child view's size is calculated incorrectly if the child and grand child have MatchParent Specification.
+                    // e.g. Let parent view's width be 200 and parent has 2 children.
+                    //      Then, child layout's measured width becomes 200 and child view's width becomes 100. (by dali-toolkit's YOGA APIs)
+                    //      Then, grand child layout's measured width becomes 200 and grand child view's width becomes 200. (by NUI Layout)
+                    //
+                    // To resolve the above issue, child layout's measured size is set with the child view's size calculated by dali-toolkit's YOGA APIs.
+                    MeasureSpecification widthSpec = new MeasureSpecification(new LayoutLength(frame.Z - frame.X), MeasureSpecification.ModeType.Exactly);
+                    MeasureSpecification heightSpec = new MeasureSpecification(new LayoutLength(frame.W - frame.Y), MeasureSpecification.ModeType.Exactly);
+                    MeasureChildWithMargins(childLayout, widthSpec, new LayoutLength(0), heightSpec, new LayoutLength(0));
+
+                    childLayout.Layout(new LayoutLength(frame.X), new LayoutLength(frame.Y), new LayoutLength(frame.Z), new LayoutLength(frame.W));
                     frame.Dispose();
                 }
             }