[NUI] change amount of Notificaion step (#1930)

Change default notification step value and add new property to modify
it.

Co-authored-by: neostom432 <neostom432@nate.com>
Co-authored-by: dongsug-song <35130733+dongsug-song@users.noreply.github.com>

diff --git a/src/Tizen.NUI.Components/Controls/ScrollableBase.cs b/src/Tizen.NUI.Components/Controls/ScrollableBase.cs
index 1f40c90..0c072d5 100755 (executable)
--- a/src/Tizen.NUI.Components/Controls/ScrollableBase.cs
+++ b/src/Tizen.NUI.Components/Controls/ScrollableBase.cs
@@ -66,6 +66,7 @@ namespace Tizen.NUI.Components
         private int mScrollDuration = 125;
         private int mPageWidth = 0;
         private float mPageFlickThreshold = 0.4f;
+        private float mScrollingEventThreshold = 0.00001f;
 
         private class ScrollableBaseCustomLayout : LayoutGroup
         {
@@ -442,6 +443,29 @@ namespace Tizen.NUI.Components
         public float DecelerationThreshold { get; set; } = 0.1f;
 
         /// <summary>
+        /// Scrolling event will be thrown when this amount of scroll positino is changed.
+        /// </summary>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public float ScrollingEventThreshold
+        {
+            get
+            {
+                return mScrollingEventThreshold;
+            }
+            set
+            {
+                if (mScrollingEventThreshold != value && value > 0)
+                {
+                    ContentContainer.RemovePropertyNotification(propertyNotification);
+                    propertyNotification = ContentContainer.AddPropertyNotification("position", PropertyCondition.Step(value));
+                    propertyNotification.Notified += OnPropertyChanged;
+                    mScrollingEventThreshold = value;
+                }
+            }
+        }
+
+
+        /// <summary>
         /// Page will be changed when velocity of panning is over threshold.
         /// The unit of threshold is pixel per milisec.
         /// </summary>
@@ -523,7 +547,7 @@ namespace Tizen.NUI.Components
                 Layout = new AbsoluteLayout() { SetPositionByLayout = false },
             };
             ContentContainer.Relayout += OnScrollingChildRelayout;
-            propertyNotification = ContentContainer.AddPropertyNotification("position", PropertyCondition.Step(1.0f));
+            propertyNotification = ContentContainer.AddPropertyNotification("position", PropertyCondition.Step(mScrollingEventThreshold));
             propertyNotification.Notified += OnPropertyChanged;
             base.Add(ContentContainer);
 
@@ -839,6 +863,8 @@ namespace Tizen.NUI.Components
                     mPanGestureDetector.Dispose();
                     mPanGestureDetector = null;
                 }
+
+                propertyNotification.Dispose();
             }
             base.Dispose(type);
         }