[NUI] Add forward and backward direction type (#3932)

Now, You can get Forward type by pressing Tab key and Backward type by pressing Shift-Tab key.

public override View GetNextFocusableView(View currentFocusedView, View.FocusDirection direction, bool loopEnabled)
{
 if (direction == View.FocusDirection.Forward)
 {
  // Tab
 }
 else if (direction == View.FocusDirection.Backward)
 {
  // Shift-Tab
 }
}

diff --git a/src/Tizen.NUI/src/public/BaseComponents/ViewEnum.cs b/src/Tizen.NUI/src/public/BaseComponents/ViewEnum.cs
index bbc1e6e..eb15127 100755 (executable)
--- a/src/Tizen.NUI/src/public/BaseComponents/ViewEnum.cs
+++ b/src/Tizen.NUI/src/public/BaseComponents/ViewEnum.cs
@@ -140,7 +140,17 @@ namespace Tizen.NUI.BaseComponents
             /// Move keyboard focus towards the next page direction.
             /// </summary>
             /// <since_tizen> 3 </since_tizen>
-            PageDown
+            PageDown,
+            /// <summary>
+            /// Move keyboard focus towards the forward direction.
+            /// </summary>
+            [EditorBrowsable(EditorBrowsableState.Never)]
+            Forward,
+            /// <summary>
+            /// Move keyboard focus towards the backward direction.
+            /// </summary>
+            [EditorBrowsable(EditorBrowsableState.Never)]
+            Backward,
         }
 
         internal enum PropertyRange