From 8c5dd17225591d5318e76e085e5d36fc3d256f30 Mon Sep 17 00:00:00 2001
From: "joogab.yun" <joogab.yun@samsung.com>
Date: Fri, 15 Oct 2021 13:57:15 +0900
Subject: [PATCH] [NUI] Check if pan gesture need to propagation

If it's a nested scroll, calculate whether the gesture should be sent to the parent.
---
 .../Controls/ScrollableBase.cs                     | 30 ++++++++++++++--------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/Tizen.NUI.Components/Controls/ScrollableBase.cs b/src/Tizen.NUI.Components/Controls/ScrollableBase.cs
index 98078bf..d0f323a 100755
--- a/src/Tizen.NUI.Components/Controls/ScrollableBase.cs
+++ b/src/Tizen.NUI.Components/Controls/ScrollableBase.cs
@@ -1329,25 +1329,19 @@ namespace Tizen.NUI.Components
 
         private void OnPanGestureDetected(object source, PanGestureDetector.DetectedEventArgs e)
         {
-            OnPanGesture(e.PanGesture);
-            if(!((SnapToPage && scrollAnimation != null && scrollAnimation.State == Animation.States.Playing) || e.PanGesture.State == Gesture.StateType.Started))
-            {
-                e.Handled = !((int)finalTargetPosition == 0 || -(int)finalTargetPosition == (int)maxScrollDistance);
-            }
+            e.Handled = OnPanGesture(e.PanGesture);
         }
 
-        private void OnPanGesture(PanGesture panGesture)
+        private bool OnPanGesture(PanGesture panGesture)
         {
+            bool handled = true;
             if (SnapToPage && scrollAnimation != null && scrollAnimation.State == Animation.States.Playing)
             {
-                return;
+                return handled;
             }
-
             if (panGesture.State == Gesture.StateType.Started)
             {
                 readyToNotice = false;
-                //Interrupt touching when panning is started
-                this.InterceptTouchEvent += OnInterruptTouchingChildTouched;
                 AttachOverShootingShadowView();
                 Debug.WriteLineIf(LayoutDebugScrollableBase, "Gesture Start");
                 if (scrolling && !SnapToPage)
@@ -1355,6 +1349,21 @@ namespace Tizen.NUI.Components
                     StopScroll();
                 }
                 totalDisplacementForPan = 0.0f;
+
+                // check if gesture need to propagation
+                var checkDisplacement = (ScrollingDirection == Direction.Horizontal) ? panGesture.Displacement.X : panGesture.Displacement.Y;
+                var checkChildCurrentPosition = (ScrollingDirection == Direction.Horizontal) ? ContentContainer.PositionX : ContentContainer.PositionY;
+                var checkChildTargetPosition = checkChildCurrentPosition + checkDisplacement;
+                var checkFinalTargetPosition = BoundScrollPosition(checkChildTargetPosition);
+                handled = !((int)checkFinalTargetPosition == 0 || -(int)checkFinalTargetPosition == (int)maxScrollDistance);
+                // If you propagate a gesture event, return;
+                if(!handled)
+                {
+                    return handled;
+                }
+
+                //Interrupt touching when panning is started
+                this.InterceptTouchEvent += OnInterruptTouchingChildTouched;
                 OnScrollDragStarted();
             }
             else if (panGesture.State == Gesture.StateType.Continuing)
@@ -1421,6 +1430,7 @@ namespace Tizen.NUI.Components
                 readyToNotice = true;
                 OnScrollAnimationStarted();
             }
+            return handled;
         }
 
         internal void BaseRemove(View view)
-- 
2.7.4