1 /* Copyright (c) 2021 Samsung Electronics Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
17 using Tizen.NUI.BaseComponents;
18 using System.Collections.Generic;
19 using System.ComponentModel;
20 using System.Diagnostics;
21 using System.Runtime.InteropServices;
22 using Tizen.NUI.Accessibility;
24 namespace Tizen.NUI.Components
27 /// ScrollEventArgs is a class to record scroll event arguments which will sent to user.
29 /// <since_tizen> 8 </since_tizen>
30 [global::System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1001: Types that own disposable fields should be disposable.", Justification = "Scroll event is temporarily used for notifying scroll position update, so position will not be disposed during the event processing.")]
31 public class ScrollEventArgs : EventArgs
33 // Position class is derived class of Disposable class and they will be implicitly disposed by DisposeQueue,
34 // so that there will be no memory leak.
35 private Position position;
36 private Position scrollPosition;
39 /// Default constructor.
41 /// <param name="position">Current container position</param>
42 /// <since_tizen> 8 </since_tizen>
43 public ScrollEventArgs(Position position)
45 this.position = position;
46 this.scrollPosition = new Position(-position);
50 /// Current position of ContentContainer.
52 /// <since_tizen> 8 </since_tizen>
53 public Position Position
61 /// Current scroll position of scrollableBase pan.
62 /// This is the position in the opposite direction to the current position of ContentContainer.
64 [EditorBrowsable(EditorBrowsableState.Never)]
65 public Position ScrollPosition
69 return scrollPosition;
75 /// ScrollOutofBoundEventArgs is to record scroll out-of-bound event arguments which will be sent to user.
77 [EditorBrowsable(EditorBrowsableState.Never)]
78 public class ScrollOutOfBoundEventArgs : EventArgs
81 /// The direction to be touched.
83 [EditorBrowsable(EditorBrowsableState.Never)]
89 [EditorBrowsable(EditorBrowsableState.Never)]
95 [EditorBrowsable(EditorBrowsableState.Never)]
101 [EditorBrowsable(EditorBrowsableState.Never)]
107 [EditorBrowsable(EditorBrowsableState.Never)]
114 /// <param name="direction">Current pan direction</param>
115 /// <param name="displacement">Current total displacement</param>
116 [EditorBrowsable(EditorBrowsableState.Never)]
117 public ScrollOutOfBoundEventArgs(Direction direction, float displacement)
119 PanDirection = direction;
120 Displacement = displacement;
124 /// Current pan direction of ContentContainer.
126 [EditorBrowsable(EditorBrowsableState.Never)]
127 public Direction PanDirection
133 /// Current total displacement of ContentContainer.
134 /// if its value is greater than 0, it is at the top/left;
135 /// if less than 0, it is at the bottom/right.
137 [EditorBrowsable(EditorBrowsableState.Never)]
138 public float Displacement
145 /// This class provides a View that can scroll a single View with a layout. This View can be a nest of Views.
147 /// <since_tizen> 8 </since_tizen>
148 public partial class ScrollableBase : Control
150 static bool LayoutDebugScrollableBase = false; // Debug flag
151 static bool focusDebugScrollableBase = false; // Debug flag
152 private Direction mScrollingDirection = Direction.Vertical;
153 private bool mScrollEnabled = true;
154 private int mScrollDuration = 125;
155 private int mPageWidth = 0;
156 private float mPageFlickThreshold = 0.4f;
157 private float mScrollingEventThreshold = 0.001f;
158 private bool fadeScrollbar = true;
160 private class ScrollableBaseCustomLayout : AbsoluteLayout
162 protected override void OnMeasure(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
164 MeasuredSize.StateType childWidthState = MeasuredSize.StateType.MeasuredSizeOK;
165 MeasuredSize.StateType childHeightState = MeasuredSize.StateType.MeasuredSizeOK;
167 Direction scrollingDirection = Direction.Vertical;
168 ScrollableBase scrollableBase = this.Owner as ScrollableBase;
169 if (scrollableBase != null)
171 scrollingDirection = scrollableBase.ScrollingDirection;
174 float totalWidth = 0.0f;
175 float totalHeight = 0.0f;
177 // measure child, should be a single scrolling child
178 foreach (LayoutItem childLayout in LayoutChildren)
180 if (childLayout != null && childLayout.Owner.Name == "ContentContainer")
183 // Use an Unspecified MeasureSpecification mode so scrolling child is not restricted to it's parents size in Height (for vertical scrolling)
184 // or Width for horizontal scrolling
185 if (scrollingDirection == Direction.Vertical)
187 MeasureSpecification unrestrictedMeasureSpec = new MeasureSpecification(heightMeasureSpec.Size, MeasureSpecification.ModeType.Unspecified);
188 MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), unrestrictedMeasureSpec, new LayoutLength(0)); // Height unrestricted by parent
192 MeasureSpecification unrestrictedMeasureSpec = new MeasureSpecification(widthMeasureSpec.Size, MeasureSpecification.ModeType.Unspecified);
193 MeasureChildWithMargins(childLayout, unrestrictedMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0)); // Width unrestricted by parent
196 totalWidth = (childLayout.MeasuredWidth.Size + (childLayout.Padding.Start + childLayout.Padding.End)).AsDecimal();
197 totalHeight = (childLayout.MeasuredHeight.Size + (childLayout.Padding.Top + childLayout.Padding.Bottom)).AsDecimal();
199 if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
201 childWidthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
203 if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
205 childHeightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
210 MeasuredSize widthSizeAndState = ResolveSizeAndState(new LayoutLength(totalWidth), widthMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
211 MeasuredSize heightSizeAndState = ResolveSizeAndState(new LayoutLength(totalHeight), heightMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
212 totalWidth = widthSizeAndState.Size.AsDecimal();
213 totalHeight = heightSizeAndState.Size.AsDecimal();
215 // Ensure layout respects it's given minimum size
216 totalWidth = Math.Max(totalWidth, SuggestedMinimumWidth.AsDecimal());
217 totalHeight = Math.Max(totalHeight, SuggestedMinimumHeight.AsDecimal());
219 widthSizeAndState.State = childWidthState;
220 heightSizeAndState.State = childHeightState;
222 SetMeasuredDimensions(ResolveSizeAndState(new LayoutLength(totalWidth), widthMeasureSpec, childWidthState),
223 ResolveSizeAndState(new LayoutLength(totalHeight), heightMeasureSpec, childHeightState));
225 // Size of ScrollableBase is changed. Change Page width too.
226 if (scrollableBase != null)
228 scrollableBase.mPageWidth = (int)MeasuredWidth.Size.AsRoundedValue();
229 scrollableBase.OnScrollingChildRelayout(null, null);
232 } // ScrollableBaseCustomLayout
235 /// The direction axis to scroll.
237 /// <since_tizen> 8 </since_tizen>
238 public enum Direction
243 /// <since_tizen> 8 </since_tizen>
249 /// <since_tizen> 8 </since_tizen>
254 /// Scrolling direction mode.
255 /// Default is Vertical scrolling.
257 /// <since_tizen> 8 </since_tizen>
258 public Direction ScrollingDirection
262 return (Direction)GetValue(ScrollingDirectionProperty);
266 SetValue(ScrollingDirectionProperty, value);
267 NotifyPropertyChanged();
270 private Direction InternalScrollingDirection
274 return mScrollingDirection;
278 if (value != mScrollingDirection)
280 //Reset scroll position and stop scroll animation
283 mScrollingDirection = value;
284 mPanGestureDetector.ClearAngles();
285 mPanGestureDetector.AddDirection(value == Direction.Horizontal ?
286 PanGestureDetector.DirectionHorizontal : PanGestureDetector.DirectionVertical);
288 ContentContainer.WidthSpecification = ScrollingDirection == Direction.Vertical ? LayoutParamPolicies.MatchParent : LayoutParamPolicies.WrapContent;
289 ContentContainer.HeightSpecification = ScrollingDirection == Direction.Vertical ? LayoutParamPolicies.WrapContent : LayoutParamPolicies.MatchParent;
296 /// Enable or disable scrolling.
298 /// <since_tizen> 8 </since_tizen>
299 public bool ScrollEnabled
303 return (bool)GetValue(ScrollEnabledProperty);
307 SetValue(ScrollEnabledProperty, value);
308 NotifyPropertyChanged();
311 private bool InternalScrollEnabled
315 return mScrollEnabled;
319 if (value != mScrollEnabled)
321 mScrollEnabled = value;
324 mPanGestureDetector.Detected += OnPanGestureDetected;
328 mPanGestureDetector.Detected -= OnPanGestureDetected;
335 /// Gets scrollable status.
337 [EditorBrowsable(EditorBrowsableState.Never)]
338 protected override bool AccessibilityIsScrollable()
344 /// Pages mode, enables moving to the next or return to current page depending on pan displacement.
345 /// Default is false.
347 /// <since_tizen> 8 </since_tizen>
348 public bool SnapToPage
352 return (bool)GetValue(SnapToPageProperty);
356 SetValue(SnapToPageProperty, value);
357 NotifyPropertyChanged();
360 private bool InternalSnapToPage { set; get; } = false;
363 /// Get current page.
364 /// Working property with SnapToPage property.
366 /// <since_tizen> 8 </since_tizen>
367 public int CurrentPage { get; private set; } = 0;
370 /// Duration of scroll animation.
371 /// Default value is 125ms.
373 /// <since_tizen> 8 </since_tizen>
374 public int ScrollDuration
378 return (int)GetValue(ScrollDurationProperty);
382 SetValue(ScrollDurationProperty, value);
383 NotifyPropertyChanged();
386 private int InternalScrollDuration
390 mScrollDuration = value >= 0 ? value : mScrollDuration;
394 return mScrollDuration;
399 /// Scroll Available area.
401 /// <since_tizen> 8 </since_tizen>
402 public Vector2 ScrollAvailableArea
406 return GetValue(ScrollAvailableAreaProperty) as Vector2;
410 SetValue(ScrollAvailableAreaProperty, value);
411 NotifyPropertyChanged();
414 private Vector2 InternalScrollAvailableArea { set; get; }
417 /// An event emitted when user starts dragging ScrollableBase, user can subscribe or unsubscribe to this event handler.<br />
419 /// <since_tizen> 8 </since_tizen>
420 public event EventHandler<ScrollEventArgs> ScrollDragStarted;
423 /// An event emitted when user stops dragging ScrollableBase, user can subscribe or unsubscribe to this event handler.<br />
425 /// <since_tizen> 8 </since_tizen>
426 public event EventHandler<ScrollEventArgs> ScrollDragEnded;
429 /// An event emitted when the scrolling slide animation starts, user can subscribe or unsubscribe to this event handler.<br />
431 /// <since_tizen> 8 </since_tizen>
432 public event EventHandler<ScrollEventArgs> ScrollAnimationStarted;
435 /// An event emitted when the scrolling slide animation ends, user can subscribe or unsubscribe to this event handler.<br />
437 /// <since_tizen> 8 </since_tizen>
438 public event EventHandler<ScrollEventArgs> ScrollAnimationEnded;
441 /// An event emitted when scrolling, user can subscribe or unsubscribe to this event handler.<br />
443 /// <since_tizen> 8 </since_tizen>
444 public event EventHandler<ScrollEventArgs> Scrolling;
447 /// An event emitted when scrolling out of bound, user can subscribe or unsubscribe to this event handler.<br />
449 [EditorBrowsable(EditorBrowsableState.Never)]
450 public event EventHandler<ScrollOutOfBoundEventArgs> ScrollOutOfBound;
453 /// Scrollbar for ScrollableBase.
455 /// <since_tizen> 8 </since_tizen>
456 public ScrollbarBase Scrollbar
460 return GetValue(ScrollbarProperty) as ScrollbarBase;
464 SetValue(ScrollbarProperty, value);
465 NotifyPropertyChanged();
468 private ScrollbarBase InternalScrollbar
478 base.Remove(scrollBar);
482 if (scrollBar != null)
484 scrollBar.Name = "ScrollBar";
502 /// Always hide Scrollbar.
504 /// <since_tizen> 8 </since_tizen>
505 public bool HideScrollbar
509 return (bool)GetValue(HideScrollbarProperty);
513 SetValue(HideScrollbarProperty, value);
514 NotifyPropertyChanged();
517 private bool InternalHideScrollbar
521 return hideScrollbar;
525 hideScrollbar = value;
538 scrollBar.Opacity = 1.0f;
547 /// The boolean flag for automatic fading Scrollbar.
548 /// Scrollbar will be faded out when scroll stay in certain position longer than the threshold.
549 /// Scrollbar will be faded in scroll position changes.
551 [EditorBrowsable(EditorBrowsableState.Never)]
552 public bool FadeScrollbar
554 get => (bool)GetValue(FadeScrollbarProperty);
555 set => SetValue(FadeScrollbarProperty, value);
558 private bool InternalFadeScrollbar
562 return fadeScrollbar;
566 fadeScrollbar = value;
568 if (scrollBar != null && !hideScrollbar)
576 scrollBar.Opacity = 1.0f;
577 // Removing fadeout timer and animation.
585 /// Container which has content of ScrollableBase.
587 /// <since_tizen> 8 </since_tizen>
588 public View ContentContainer { get; private set; }
591 /// Set the layout on this View. Replaces any existing Layout.
593 /// <since_tizen> 8 </since_tizen>
594 public new LayoutItem Layout
598 return GetValue(LayoutProperty) as LayoutItem;
602 SetValue(LayoutProperty, value);
603 NotifyPropertyChanged();
606 private LayoutItem InternalLayout
610 return ContentContainer.Layout;
614 ContentContainer.Layout = value;
619 /// List of children of Container.
621 /// <since_tizen> 8 </since_tizen>
622 public new List<View> Children
626 return ContentContainer.Children;
631 /// Deceleration rate of scrolling by finger.
632 /// Rate should be bigger than 0 and smaller than 1.
633 /// Default value is 0.998f;
635 /// <since_tizen> 8 </since_tizen>
636 public float DecelerationRate
640 return (float)GetValue(DecelerationRateProperty);
644 SetValue(DecelerationRateProperty, value);
645 NotifyPropertyChanged();
648 private float InternalDecelerationRate
652 return decelerationRate;
656 decelerationRate = (value < 1 && value > 0) ? value : decelerationRate;
657 logValueOfDeceleration = (float)Math.Log(value);
662 /// Threshold not to go infinite at the end of scrolling animation.
664 [EditorBrowsable(EditorBrowsableState.Never)]
665 public float DecelerationThreshold
669 return (float)GetValue(DecelerationThresholdProperty);
673 SetValue(DecelerationThresholdProperty, value);
674 NotifyPropertyChanged();
677 private float InternalDecelerationThreshold { get; set; } = 0.1f;
680 /// Scrolling event will be thrown when this amount of scroll position is changed.
681 /// If this threshold becomes smaller, the tracking detail increases but the scrolling range that can be tracked becomes smaller.
682 /// If large sized ContentContainer is required, please use larger threshold value.
683 /// Default ScrollingEventThreshold value is 0.001f.
685 [EditorBrowsable(EditorBrowsableState.Never)]
686 public float ScrollingEventThreshold
690 return (float)GetValue(ScrollingEventThresholdProperty);
694 SetValue(ScrollingEventThresholdProperty, value);
695 NotifyPropertyChanged();
698 private float InternalScrollingEventThreshold
702 return mScrollingEventThreshold;
706 if (mScrollingEventThreshold != value && value > 0)
708 ContentContainer.RemovePropertyNotification(propertyNotification);
709 propertyNotification = ContentContainer.AddPropertyNotification("position", PropertyCondition.Step(value));
710 propertyNotification.Notified += OnPropertyChanged;
711 mScrollingEventThreshold = value;
717 /// Page will be changed when velocity of panning is over threshold.
718 /// The unit of threshold is pixel per millisecond.
720 /// <since_tizen> 8 </since_tizen>
721 public float PageFlickThreshold
725 return (float)GetValue(PageFlickThresholdProperty);
729 SetValue(PageFlickThresholdProperty, value);
730 NotifyPropertyChanged();
733 private float InternalPageFlickThreshold
737 return mPageFlickThreshold;
741 mPageFlickThreshold = value >= 0f ? value : mPageFlickThreshold;
746 /// Padding for the ScrollableBase
748 [EditorBrowsable(EditorBrowsableState.Never)]
749 public new Extents Padding
753 return GetValue(PaddingProperty) as Extents;
757 SetValue(PaddingProperty, value);
758 NotifyPropertyChanged();
761 private Extents InternalPadding
765 return ContentContainer.Padding;
769 ContentContainer.Padding = value;
774 /// Alphafunction for scroll animation.
776 [EditorBrowsable(EditorBrowsableState.Never)]
777 public AlphaFunction ScrollAlphaFunction
781 return GetValue(ScrollAlphaFunctionProperty) as AlphaFunction;
785 SetValue(ScrollAlphaFunctionProperty, value);
786 NotifyPropertyChanged();
789 private AlphaFunction InternalScrollAlphaFunction { get; set; } = new AlphaFunction(AlphaFunction.BuiltinFunctions.Linear);
791 private bool hideScrollbar = true;
792 private float maxScrollDistance;
793 private float childTargetPosition = 0.0f;
794 private PanGestureDetector mPanGestureDetector;
795 private ScrollbarBase scrollBar;
796 private bool scrolling = false;
797 private float ratioOfScreenWidthToCompleteScroll = 0.5f;
798 private float totalDisplacementForPan = 0.0f;
799 private Size previousContainerSize = new Size();
800 private Size previousSize = new Size();
801 private PropertyNotification propertyNotification;
802 private float noticeAnimationEndBeforePosition = 0.0f;
803 private bool readyToNotice = false;
806 /// Notice before animation is finished.
808 [EditorBrowsable(EditorBrowsableState.Never)]
809 // Let's consider more whether this needs to be set as protected.
810 public float NoticeAnimationEndBeforePosition
814 return (float)GetValue(NoticeAnimationEndBeforePositionProperty);
818 SetValue(NoticeAnimationEndBeforePositionProperty, value);
819 NotifyPropertyChanged();
822 private float InternalNoticeAnimationEndBeforePosition
824 get => noticeAnimationEndBeforePosition;
825 set => noticeAnimationEndBeforePosition = value;
829 /// Step scroll move distance.
830 /// Key focus originally moves focusable objects, but in ScrollableBase,
831 /// if focusable object is too far or un-exist and ScrollableBase is focusable,
832 /// it can scroll move itself by key input.
833 /// this value decide how long distance will it moves in one step.
834 /// if any value is not set, step will be moved quater size of ScrollableBase length.
836 [EditorBrowsable(EditorBrowsableState.Never)]
837 public float StepScrollDistance
841 return (float)GetValue(StepScrollDistanceProperty);
845 SetValue(StepScrollDistanceProperty, value);
846 NotifyPropertyChanged();
849 private float stepScrollDistance = 0f;
852 /// Wheel scroll move distance.
853 /// This value decide how long distance will it moves in wheel event.
855 [EditorBrowsable(EditorBrowsableState.Never)]
856 public float WheelScrollDistance
860 return (float)GetValue(WheelScrollDistanceProperty);
864 SetValue(WheelScrollDistanceProperty, value);
865 NotifyPropertyChanged();
868 private float wheelScrollDistance = 50f;
871 // Let's consider more whether this needs to be set as protected.
872 private float finalTargetPosition;
874 private Animation scrollAnimation;
875 // Declare user alpha function delegate
876 [UnmanagedFunctionPointer(CallingConvention.StdCall)]
877 private delegate float UserAlphaFunctionDelegate(float progress);
878 private UserAlphaFunctionDelegate customScrollAlphaFunction;
879 private float velocityOfLastPan = 0.0f;
880 private float panAnimationDuration = 0.0f;
881 private float panAnimationDelta = 0.0f;
882 private float logValueOfDeceleration = 0.0f;
883 private float decelerationRate = 0.0f;
885 private View topOverShootingShadowView;
886 private View bottomOverShootingShadowView;
887 private View leftOverShootingShadowView;
888 private View rightOverShootingShadowView;
889 private const int overShootingShadowScaleHeightLimit = 64 * 3;
890 private const int overShootingShadowAnimationDuration = 300;
891 private Animation overShootingShadowAnimation;
892 private bool isOverShootingShadowShown = false;
893 private float startShowShadowDisplacement;
895 private void Initialize()
897 DecelerationRate = 0.998f;
899 base.Layout = new ScrollableBaseCustomLayout();
900 mPanGestureDetector = new PanGestureDetector();
901 mPanGestureDetector.Attach(this);
902 mPanGestureDetector.AddDirection(PanGestureDetector.DirectionVertical);
903 if (mPanGestureDetector.GetMaximumTouchesRequired() < 2) mPanGestureDetector.SetMaximumTouchesRequired(2);
904 mPanGestureDetector.Detected += OnPanGestureDetected;
906 ClippingMode = ClippingModeType.ClipToBoundingBox;
908 //Default Scrolling child
909 ContentContainer = new View()
911 Name = "ContentContainer",
912 WidthSpecification = ScrollingDirection == Direction.Vertical ? LayoutParamPolicies.MatchParent : LayoutParamPolicies.WrapContent,
913 HeightSpecification = ScrollingDirection == Direction.Vertical ? LayoutParamPolicies.WrapContent : LayoutParamPolicies.MatchParent,
915 // Check if children's sizes change to update Scrollbar
916 ContentContainer.Relayout += OnScrollingChildRelayout;
917 propertyNotification = ContentContainer.AddPropertyNotification("position", PropertyCondition.Step(mScrollingEventThreshold));
918 propertyNotification.Notified += OnPropertyChanged;
919 base.Add(ContentContainer);
920 // Check if ScrollableBase's size changes to update Scrollbar
921 base.Relayout += OnScrollingChildRelayout;
923 Scrollbar = new Scrollbar();
925 //Show vertical shadow on the top (or bottom) of the scrollable when panning down (or up).
926 topOverShootingShadowView = new View
928 BackgroundImage = FrameworkInformation.ResourcePath + "nui_component_default_scroll_over_shooting_top.png",
931 PositionUsesPivotPoint = true,
932 ParentOrigin = NUI.ParentOrigin.TopCenter,
933 PivotPoint = NUI.PivotPoint.TopCenter,
935 bottomOverShootingShadowView = new View
937 BackgroundImage = FrameworkInformation.ResourcePath + "nui_component_default_scroll_over_shooting_bottom.png",
940 PositionUsesPivotPoint = true,
941 ParentOrigin = NUI.ParentOrigin.BottomCenter,
942 PivotPoint = NUI.PivotPoint.BottomCenter,
944 //Show horizontal shadow on the left (or right) of the scrollable when panning down (or up).
945 leftOverShootingShadowView = new View
947 BackgroundImage = FrameworkInformation.ResourcePath + "nui_component_default_scroll_over_shooting_left.png",
950 PositionUsesPivotPoint = true,
951 ParentOrigin = NUI.ParentOrigin.CenterLeft,
952 PivotPoint = NUI.PivotPoint.CenterLeft,
954 rightOverShootingShadowView = new View
956 BackgroundImage = FrameworkInformation.ResourcePath + "nui_component_default_scroll_over_shooting_right.png",
959 PositionUsesPivotPoint = true,
960 ParentOrigin = NUI.ParentOrigin.CenterRight,
961 PivotPoint = NUI.PivotPoint.CenterRight,
964 WheelEvent += OnWheelEvent;
966 AccessibilityManager.Instance.SetAccessibilityAttribute(this, AccessibilityManager.AccessibilityAttribute.Trait, "ScrollableBase");
968 SetKeyboardNavigationSupport(true);
972 /// Default Constructor
974 /// <since_tizen> 8 </since_tizen>
975 public ScrollableBase() : base()
981 /// Creates a new instance of a ScrollableBase with style.
983 /// <param name="style">A style applied to the newly created ScrollableBase.</param>
984 [EditorBrowsable(EditorBrowsableState.Never)]
985 public ScrollableBase(ControlStyle style) : base(style)
990 private bool OnInterruptTouchingChildTouched(object source, View.TouchEventArgs args)
992 if (args.Touch.GetState(0) == PointStateType.Down)
994 if (scrolling && !SnapToPage)
1002 private void OnPropertyChanged(object source, PropertyNotification.NotifyEventArgs args)
1008 /// Called after a child has been added to the owning view.
1010 /// <param name="view">The child which has been added.</param>
1011 /// <since_tizen> 8 </since_tizen>
1012 public override void Add(View view)
1014 ContentContainer.Add(view);
1018 /// Called after a child has been removed from the owning view.
1020 /// <param name="view">The child which has been removed.</param>
1021 /// <since_tizen> 8 </since_tizen>
1022 public override void Remove(View view)
1024 if (SnapToPage && CurrentPage == Children.IndexOf(view) && CurrentPage == Children.Count - 1 && Children.Count > 1)
1026 // Target View is current page and also last child.
1027 // CurrentPage should be changed to previous page.
1028 ScrollToIndex(CurrentPage - 1);
1031 ContentContainer.Remove(view);
1034 private void OnScrollingChildRelayout(object source, EventArgs args)
1036 // Size is changed. Calculate maxScrollDistance.
1037 bool isSizeChanged = previousContainerSize.Width != ContentContainer.Size.Width || previousContainerSize.Height != ContentContainer.Size.Height ||
1038 previousSize.Width != Size.Width || previousSize.Height != Size.Height;
1042 maxScrollDistance = CalculateMaximumScrollDistance();
1043 if (!ReviseContainerPositionIfNeed())
1049 previousContainerSize = new Size(ContentContainer.Size);
1050 previousSize = new Size(Size);
1053 private bool ReviseContainerPositionIfNeed()
1055 bool isHorizontal = ScrollingDirection == Direction.Horizontal;
1056 float currentPosition = isHorizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y;
1058 if (Math.Abs(currentPosition) > maxScrollDistance)
1061 var targetPosition = BoundScrollPosition(-maxScrollDistance);
1062 if (isHorizontal) ContentContainer.PositionX = targetPosition;
1063 else ContentContainer.PositionY = targetPosition;
1071 /// The composition of a Scrollbar can vary depending on how you use ScrollableBase.
1072 /// Set the composition that will go into the ScrollableBase according to your ScrollableBase.
1074 /// <since_tizen> 8 </since_tizen>
1075 [EditorBrowsable(EditorBrowsableState.Never)]
1076 protected virtual void SetScrollbar()
1080 bool isHorizontal = ScrollingDirection == Direction.Horizontal;
1081 float contentLength = isHorizontal ? ContentContainer.Size.Width : ContentContainer.Size.Height;
1082 float viewportLength = isHorizontal ? Size.Width : Size.Height;
1083 float currentPosition = isHorizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y;
1084 Scrollbar.Initialize(contentLength, viewportLength, -currentPosition, isHorizontal);
1088 /// Update scrollbar position and size.
1089 [EditorBrowsable(EditorBrowsableState.Never)]
1090 protected virtual void UpdateScrollbar()
1094 bool isHorizontal = ScrollingDirection == Direction.Horizontal;
1095 float contentLength = isHorizontal ? ContentContainer.Size.Width : ContentContainer.Size.Height;
1096 float viewportLength = isHorizontal ? Size.Width : Size.Height;
1097 float currentPosition = isHorizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y;
1098 Scrollbar.Update(contentLength, viewportLength, -currentPosition);
1100 if (!hideScrollbar && fadeScrollbar)
1102 Scrollbar.FadeOut();
1108 /// Scrolls to the item at the specified index.
1110 /// <param name="index">Index of item.</param>
1111 /// <since_tizen> 8 </since_tizen>
1112 public void ScrollToIndex(int index)
1114 if (ContentContainer.ChildCount - 1 < index || index < 0)
1121 CurrentPage = index;
1124 float targetPosition = Math.Min(ScrollingDirection == Direction.Vertical ? Children[index].Position.Y : Children[index].Position.X, maxScrollDistance);
1125 AnimateChildTo(ScrollDuration, -targetPosition);
1128 internal void ScrollToChild(View child, bool anim = false)
1130 if (null == FindDescendantByID(child.ID)) return;
1132 bool isHorizontal = (ScrollingDirection == Direction.Horizontal);
1134 float viewScreenPosition = (isHorizontal ? ScreenPosition.X : ScreenPosition.Y);
1135 float childScreenPosition = (isHorizontal ? child.ScreenPosition.X : child.ScreenPosition.Y);
1136 float scrollPosition = (isHorizontal ? ScrollPosition.X : ScrollPosition.Y);
1137 float viewSize = (isHorizontal ? SizeWidth : SizeHeight);
1138 float childSize = (isHorizontal ? child.SizeWidth : child.SizeHeight);
1140 if (viewScreenPosition > childScreenPosition ||
1141 viewScreenPosition + viewSize < childScreenPosition + childSize)
1142 {// if object is outside
1143 float targetPosition;
1144 float dist = viewScreenPosition - childScreenPosition;
1146 {// if object is upper side
1147 targetPosition = scrollPosition - dist;
1150 {// if object is down side
1151 targetPosition = scrollPosition - dist + childSize - viewSize;
1153 ScrollTo(targetPosition, anim);
1157 private void OnScrollDragStarted()
1159 ScrollEventArgs eventArgs = new ScrollEventArgs(ContentContainer.CurrentPosition);
1160 ScrollDragStarted?.Invoke(this, eventArgs);
1161 EmitScrollStartedEvent();
1163 if (!hideScrollbar && fadeScrollbar)
1165 scrollBar?.FadeIn();
1169 private void OnScrollDragEnded()
1171 ScrollEventArgs eventArgs = new ScrollEventArgs(ContentContainer.CurrentPosition);
1172 ScrollDragEnded?.Invoke(this, eventArgs);
1173 EmitScrollFinishedEvent();
1175 if (!hideScrollbar && fadeScrollbar)
1177 scrollBar?.FadeOut();
1181 private void OnScrollAnimationStarted()
1183 ScrollEventArgs eventArgs = new ScrollEventArgs(ContentContainer.CurrentPosition);
1184 ScrollAnimationStarted?.Invoke(this, eventArgs);
1185 EmitScrollStartedEvent();
1187 if (!hideScrollbar && fadeScrollbar)
1189 scrollBar?.FadeIn();
1193 private void OnScrollAnimationEnded()
1196 this.InterceptTouchEvent -= OnInterruptTouchingChildTouched;
1198 ScrollEventArgs eventArgs = new ScrollEventArgs(ContentContainer.CurrentPosition);
1199 ScrollAnimationEnded?.Invoke(this, eventArgs);
1200 EmitScrollFinishedEvent();
1202 if (!hideScrollbar && fadeScrollbar)
1204 scrollBar?.FadeOut();
1208 private void OnScroll()
1210 ScrollEventArgs eventArgs = new ScrollEventArgs(ContentContainer.CurrentPosition);
1211 Scrolling?.Invoke(this, eventArgs);
1213 bool isHorizontal = ScrollingDirection == Direction.Horizontal;
1214 float contentLength = isHorizontal ? ContentContainer.Size.Width : ContentContainer.Size.Height;
1215 float currentPosition = isHorizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y;
1217 scrollBar?.Update(contentLength, Math.Abs(currentPosition));
1218 CheckPreReachedTargetPosition();
1221 private void CheckPreReachedTargetPosition()
1223 // Check whether we reached pre-reached target position
1224 if (readyToNotice &&
1225 ContentContainer.CurrentPosition.Y <= finalTargetPosition + NoticeAnimationEndBeforePosition &&
1226 ContentContainer.CurrentPosition.Y >= finalTargetPosition - NoticeAnimationEndBeforePosition)
1229 readyToNotice = false;
1230 OnPreReachedTargetPosition(finalTargetPosition);
1235 /// This helps developer who wants to know before scroll is reaching target position.
1237 /// <param name="targetPosition">Index of item.</param>
1238 /// This may be public opened in tizen_6.0 after ACR done. Before ACR, need to be hidden as inhouse API
1239 [EditorBrowsable(EditorBrowsableState.Never)]
1240 protected virtual void OnPreReachedTargetPosition(float targetPosition)
1245 private void StopScroll()
1247 if (scrollAnimation != null)
1249 if (scrollAnimation.State == Animation.States.Playing)
1251 Debug.WriteLineIf(LayoutDebugScrollableBase, "StopScroll Animation Playing");
1252 scrollAnimation.Stop(Animation.EndActions.Cancel);
1253 OnScrollAnimationEnded();
1255 scrollAnimation.Clear();
1259 private void AnimateChildTo(int duration, float axisPosition)
1261 Debug.WriteLineIf(LayoutDebugScrollableBase, "AnimationTo Animation Duration:" + duration + " Destination:" + axisPosition);
1262 finalTargetPosition = axisPosition;
1264 StopScroll(); // Will replace previous animation so will stop existing one.
1266 if (scrollAnimation == null)
1268 scrollAnimation = new Animation();
1269 scrollAnimation.Finished += ScrollAnimationFinished;
1272 scrollAnimation.Duration = duration;
1273 scrollAnimation.DefaultAlphaFunction = new AlphaFunction(AlphaFunction.BuiltinFunctions.EaseOutSquare);
1274 scrollAnimation.AnimateTo(ContentContainer, (ScrollingDirection == Direction.Horizontal) ? "PositionX" : "PositionY", axisPosition, ScrollAlphaFunction);
1276 OnScrollAnimationStarted();
1277 scrollAnimation.Play();
1281 /// Scroll to specific position with or without animation.
1283 /// <param name="position">Destination.</param>
1284 /// <param name="animate">Scroll with or without animation</param>
1285 /// <since_tizen> 8 </since_tizen>
1286 public void ScrollTo(float position, bool animate)
1289 float currentPositionX = ContentContainer.CurrentPosition.X != 0 ? ContentContainer.CurrentPosition.X : ContentContainer.Position.X;
1290 float currentPositionY = ContentContainer.CurrentPosition.Y != 0 ? ContentContainer.CurrentPosition.Y : ContentContainer.Position.Y;
1291 float delta = ScrollingDirection == Direction.Horizontal ? currentPositionX : currentPositionY;
1292 // The argument position is the new pan position. So the new position of ScrollableBase becomes (-position).
1293 // To move ScrollableBase's position to (-position), it moves by (-position - currentPosition).
1294 delta = -position - delta;
1296 ScrollBy(delta, animate);
1299 private float BoundScrollPosition(float targetPosition)
1301 if (ScrollAvailableArea != null)
1303 float minScrollPosition = ScrollAvailableArea.X;
1304 float maxScrollPosition = ScrollAvailableArea.Y;
1306 targetPosition = Math.Min(-minScrollPosition, targetPosition);
1307 targetPosition = Math.Max(-maxScrollPosition, targetPosition);
1311 targetPosition = Math.Min(0, targetPosition);
1312 targetPosition = Math.Max(-maxScrollDistance, targetPosition);
1315 return targetPosition;
1318 private void ScrollBy(float displacement, bool animate)
1320 if (GetChildCount() == 0 || maxScrollDistance < 0)
1325 float childCurrentPosition = (ScrollingDirection == Direction.Horizontal) ? ContentContainer.PositionX : ContentContainer.PositionY;
1327 Debug.WriteLineIf(LayoutDebugScrollableBase, "ScrollBy childCurrentPosition:" + childCurrentPosition +
1328 " displacement:" + displacement,
1329 " maxScrollDistance:" + maxScrollDistance);
1331 childTargetPosition = childCurrentPosition + displacement; // child current position + gesture displacement
1333 Debug.WriteLineIf(LayoutDebugScrollableBase, "ScrollBy currentAxisPosition:" + childCurrentPosition + "childTargetPosition:" + childTargetPosition);
1337 // Calculate scroll animation duration
1338 float scrollDistance = Math.Abs(displacement);
1339 readyToNotice = true;
1341 AnimateChildTo(ScrollDuration, BoundScrollPosition(AdjustTargetPositionOfScrollAnimation(BoundScrollPosition(childTargetPosition))));
1346 finalTargetPosition = BoundScrollPosition(childTargetPosition);
1348 // Set position of scrolling child without an animation
1349 if (ScrollingDirection == Direction.Horizontal)
1351 ContentContainer.PositionX = finalTargetPosition;
1355 ContentContainer.PositionY = finalTargetPosition;
1361 /// you can override it to clean-up your own resources.
1363 /// <param name="type">DisposeTypes</param>
1364 /// This will be public opened in tizen_5.5 after ACR done. Before ACR, need to be hidden as inhouse API.
1365 [EditorBrowsable(EditorBrowsableState.Never)]
1366 protected override void Dispose(DisposeTypes type)
1373 StopOverShootingShadowAnimation();
1376 if (type == DisposeTypes.Explicit)
1378 mPanGestureDetector?.Dispose();
1379 mPanGestureDetector = null;
1381 ContentContainer?.RemovePropertyNotification(propertyNotification);
1382 propertyNotification?.Dispose();
1383 propertyNotification = null;
1386 WheelEvent -= OnWheelEvent;
1388 if (type == DisposeTypes.Explicit)
1395 private float CalculateMaximumScrollDistance()
1397 float scrollingChildLength = 0;
1398 float scrollerLength = 0;
1399 if (ScrollingDirection == Direction.Horizontal)
1401 Debug.WriteLineIf(LayoutDebugScrollableBase, "Horizontal");
1403 scrollingChildLength = ContentContainer.Size.Width;
1404 scrollerLength = Size.Width;
1408 Debug.WriteLineIf(LayoutDebugScrollableBase, "Vertical");
1409 scrollingChildLength = ContentContainer.Size.Height;
1410 scrollerLength = Size.Height;
1413 Debug.WriteLineIf(LayoutDebugScrollableBase, "ScrollBy maxScrollDistance:" + (scrollingChildLength - scrollerLength) +
1414 " parent length:" + scrollerLength +
1415 " scrolling child length:" + scrollingChildLength);
1417 return Math.Max(scrollingChildLength - scrollerLength, 0);
1420 private void PageSnap(float velocity)
1424 Debug.WriteLineIf(LayoutDebugScrollableBase, "PageSnap with pan candidate totalDisplacement:" + totalDisplacementForPan +
1425 " currentPage[" + CurrentPage + "]");
1427 //Increment current page if total displacement enough to warrant a page change.
1428 if (Math.Abs(totalDisplacementForPan) > (mPageWidth * ratioOfScreenWidthToCompleteScroll))
1430 if (totalDisplacementForPan < 0)
1432 CurrentPage = Math.Min(Math.Max(Children.Count - 1, 0), ++CurrentPage);
1436 CurrentPage = Math.Max(0, --CurrentPage);
1439 else if (Math.Abs(velocity) > PageFlickThreshold)
1443 CurrentPage = Math.Min(Math.Max(Children.Count - 1, 0), ++CurrentPage);
1447 CurrentPage = Math.Max(0, --CurrentPage);
1451 // Animate to new page or reposition to current page
1452 if (ScrollingDirection == Direction.Horizontal)
1453 destination = -(Children[CurrentPage].Position.X + Children[CurrentPage].CurrentSize.Width / 2 - CurrentSize.Width / 2); // set to middle of current page
1455 destination = -(Children[CurrentPage].Position.Y + Children[CurrentPage].CurrentSize.Height / 2 - CurrentSize.Height / 2);
1457 AnimateChildTo(ScrollDuration, destination);
1461 /// Enable/Disable overshooting effect. default is disabled.
1463 [EditorBrowsable(EditorBrowsableState.Never)]
1464 public bool EnableOverShootingEffect
1468 return (bool)GetValue(EnableOverShootingEffectProperty);
1472 SetValue(EnableOverShootingEffectProperty, value);
1473 NotifyPropertyChanged();
1476 private bool InternalEnableOverShootingEffect { get; set; } = false;
1478 private void AttachOverShootingShadowView()
1480 if (!EnableOverShootingEffect)
1483 // stop animation if necessary.
1484 StopOverShootingShadowAnimation();
1486 if (ScrollingDirection == Direction.Horizontal)
1488 base.Add(leftOverShootingShadowView);
1489 base.Add(rightOverShootingShadowView);
1491 leftOverShootingShadowView.Size = new Size(0.0f, SizeHeight);
1492 leftOverShootingShadowView.Opacity = 1.0f;
1493 leftOverShootingShadowView.RaiseToTop();
1495 rightOverShootingShadowView.Size = new Size(0.0f, SizeHeight);
1496 rightOverShootingShadowView.Opacity = 1.0f;
1497 rightOverShootingShadowView.RaiseToTop();
1501 base.Add(topOverShootingShadowView);
1502 base.Add(bottomOverShootingShadowView);
1504 topOverShootingShadowView.Size = new Size(SizeWidth, 0.0f);
1505 topOverShootingShadowView.Opacity = 1.0f;
1506 topOverShootingShadowView.RaiseToTop();
1508 bottomOverShootingShadowView.Size = new Size(SizeWidth, 0.0f);
1509 bottomOverShootingShadowView.Opacity = 1.0f;
1510 bottomOverShootingShadowView.RaiseToTop();
1513 // at the beginning, height or width of overshooting shadow is 0, so it is invisible.
1514 isOverShootingShadowShown = false;
1517 private void DragOverShootingShadow(float totalPanDisplacement, float panDisplacement)
1519 if (!EnableOverShootingEffect)
1522 if (totalPanDisplacement > 0) // downwards
1524 // check if reaching at the top / left.
1525 if ((int)finalTargetPosition != 0)
1527 isOverShootingShadowShown = false;
1531 // save start displacement, and re-calculate displacement.
1532 if (!isOverShootingShadowShown)
1534 startShowShadowDisplacement = totalPanDisplacement;
1536 isOverShootingShadowShown = true;
1538 float newDisplacement = (int)totalPanDisplacement < (int)startShowShadowDisplacement ? 0 : totalPanDisplacement - startShowShadowDisplacement;
1540 if (ScrollingDirection == Direction.Horizontal)
1542 // scale limit of height is 60%.
1543 float heightScale = newDisplacement / overShootingShadowScaleHeightLimit;
1544 leftOverShootingShadowView.SizeHeight = heightScale > 0.6f ? SizeHeight * 0.4f : SizeHeight * (1.0f - heightScale);
1546 // scale limit of width is 300%.
1547 leftOverShootingShadowView.SizeWidth = newDisplacement > overShootingShadowScaleHeightLimit ? overShootingShadowScaleHeightLimit : newDisplacement;
1550 ScrollOutOfBoundEventArgs.Direction scrollDirection = panDisplacement > 0 ?
1551 ScrollOutOfBoundEventArgs.Direction.Right : ScrollOutOfBoundEventArgs.Direction.Left;
1552 OnScrollOutOfBound(scrollDirection, totalPanDisplacement);
1556 // scale limit of width is 60%.
1557 float widthScale = newDisplacement / overShootingShadowScaleHeightLimit;
1558 topOverShootingShadowView.SizeWidth = widthScale > 0.6f ? SizeWidth * 0.4f : SizeWidth * (1.0f - widthScale);
1560 // scale limit of height is 300%.
1561 topOverShootingShadowView.SizeHeight = newDisplacement > overShootingShadowScaleHeightLimit ? overShootingShadowScaleHeightLimit : newDisplacement;
1564 ScrollOutOfBoundEventArgs.Direction scrollDirection = panDisplacement > 0 ?
1565 ScrollOutOfBoundEventArgs.Direction.Down : ScrollOutOfBoundEventArgs.Direction.Up;
1566 OnScrollOutOfBound(scrollDirection, totalPanDisplacement);
1569 else if (totalPanDisplacement < 0) // upwards
1571 // check if reaching at the bottom.
1572 if (-(int)finalTargetPosition != (int)maxScrollDistance)
1574 isOverShootingShadowShown = false;
1578 // save start displacement, and re-calculate displacement.
1579 if (!isOverShootingShadowShown)
1581 startShowShadowDisplacement = totalPanDisplacement;
1583 isOverShootingShadowShown = true;
1585 float newDisplacement = (int)startShowShadowDisplacement < (int)totalPanDisplacement ? 0 : startShowShadowDisplacement - totalPanDisplacement;
1587 if (ScrollingDirection == Direction.Horizontal)
1589 // scale limit of height is 60%.
1590 float heightScale = newDisplacement / overShootingShadowScaleHeightLimit;
1591 rightOverShootingShadowView.SizeHeight = heightScale > 0.6f ? SizeHeight * 0.4f : SizeHeight * (1.0f - heightScale);
1593 // scale limit of width is 300%.
1594 rightOverShootingShadowView.SizeWidth = newDisplacement > overShootingShadowScaleHeightLimit ? overShootingShadowScaleHeightLimit : newDisplacement;
1597 ScrollOutOfBoundEventArgs.Direction scrollDirection = panDisplacement > 0 ?
1598 ScrollOutOfBoundEventArgs.Direction.Right : ScrollOutOfBoundEventArgs.Direction.Left;
1599 OnScrollOutOfBound(scrollDirection, totalPanDisplacement);
1603 // scale limit of width is 60%.
1604 float widthScale = newDisplacement / overShootingShadowScaleHeightLimit;
1605 bottomOverShootingShadowView.SizeWidth = widthScale > 0.6f ? SizeWidth * 0.4f : SizeWidth * (1.0f - widthScale);
1607 // scale limit of height is 300%.
1608 bottomOverShootingShadowView.SizeHeight = newDisplacement > overShootingShadowScaleHeightLimit ? overShootingShadowScaleHeightLimit : newDisplacement;
1611 ScrollOutOfBoundEventArgs.Direction scrollDirection = panDisplacement > 0 ?
1612 ScrollOutOfBoundEventArgs.Direction.Down : ScrollOutOfBoundEventArgs.Direction.Up;
1613 OnScrollOutOfBound(scrollDirection, totalPanDisplacement);
1618 // if total displacement is 0, shadow would become invisible.
1619 isOverShootingShadowShown = false;
1623 private void PlayOverShootingShadowAnimation()
1625 if (!EnableOverShootingEffect)
1628 // stop animation if necessary.
1629 StopOverShootingShadowAnimation();
1631 if (overShootingShadowAnimation == null)
1633 overShootingShadowAnimation = new Animation(overShootingShadowAnimationDuration);
1634 overShootingShadowAnimation.Finished += OnOverShootingShadowAnimationFinished;
1637 if (ScrollingDirection == Direction.Horizontal)
1639 View targetView = totalDisplacementForPan < 0 ? rightOverShootingShadowView : leftOverShootingShadowView;
1640 overShootingShadowAnimation.AnimateTo(targetView, "SizeHeight", SizeHeight);
1641 overShootingShadowAnimation.AnimateTo(targetView, "SizeWidth", 0.0f);
1642 overShootingShadowAnimation.AnimateTo(targetView, "Opacity", 0.0f);
1646 View targetView = totalDisplacementForPan < 0 ? bottomOverShootingShadowView : topOverShootingShadowView;
1647 overShootingShadowAnimation.AnimateTo(targetView, "SizeWidth", SizeWidth);
1648 overShootingShadowAnimation.AnimateTo(targetView, "SizeHeight", 0.0f);
1649 overShootingShadowAnimation.AnimateTo(targetView, "Opacity", 0.0f);
1651 overShootingShadowAnimation.Play();
1654 private void StopOverShootingShadowAnimation()
1656 if (overShootingShadowAnimation == null || overShootingShadowAnimation.State != Animation.States.Playing)
1659 overShootingShadowAnimation.Stop(Animation.EndActions.Cancel);
1660 OnOverShootingShadowAnimationFinished(null, null);
1661 overShootingShadowAnimation.Clear();
1664 private void OnOverShootingShadowAnimationFinished(object sender, EventArgs e)
1666 if (ScrollingDirection == Direction.Horizontal)
1668 base.Remove(leftOverShootingShadowView);
1669 base.Remove(rightOverShootingShadowView);
1671 leftOverShootingShadowView.Size = new Size(0.0f, SizeHeight);
1672 rightOverShootingShadowView.Size = new Size(0.0f, SizeHeight);
1676 base.Remove(topOverShootingShadowView);
1677 base.Remove(bottomOverShootingShadowView);
1679 topOverShootingShadowView.Size = new Size(SizeWidth, 0.0f);
1680 bottomOverShootingShadowView.Size = new Size(SizeWidth, 0.0f);
1683 // after animation finished, height/width & opacity of vertical shadow both are 0, so it is invisible.
1684 isOverShootingShadowShown = false;
1687 private void OnScrollOutOfBound(ScrollOutOfBoundEventArgs.Direction direction, float displacement)
1689 ScrollOutOfBoundEventArgs args = new ScrollOutOfBoundEventArgs(direction, displacement);
1690 ScrollOutOfBound?.Invoke(this, args);
1693 private void OnPanGestureDetected(object source, PanGestureDetector.DetectedEventArgs e)
1695 e.Handled = OnPanGesture(e.PanGesture);
1698 private bool OnPanGesture(PanGesture panGesture)
1700 bool handled = true;
1701 if (SnapToPage && scrollAnimation != null && scrollAnimation.State == Animation.States.Playing)
1705 if (panGesture.State == Gesture.StateType.Started)
1707 readyToNotice = false;
1708 AttachOverShootingShadowView();
1709 Debug.WriteLineIf(LayoutDebugScrollableBase, "Gesture Start");
1710 if (scrolling && !SnapToPage)
1714 totalDisplacementForPan = 0.0f;
1716 // check if gesture need to propagation
1717 var checkDisplacement = (ScrollingDirection == Direction.Horizontal) ? panGesture.Displacement.X : panGesture.Displacement.Y;
1718 var checkChildCurrentPosition = (ScrollingDirection == Direction.Horizontal) ? ContentContainer.PositionX : ContentContainer.PositionY;
1719 var checkChildTargetPosition = checkChildCurrentPosition + checkDisplacement;
1720 var checkFinalTargetPosition = BoundScrollPosition(checkChildTargetPosition);
1721 handled = !((int)checkFinalTargetPosition == 0 || -(int)checkFinalTargetPosition == (int)maxScrollDistance);
1722 // If you propagate a gesture event, return;
1728 //Interrupt touching when panning is started
1729 this.InterceptTouchEvent += OnInterruptTouchingChildTouched;
1730 OnScrollDragStarted();
1732 else if (panGesture.State == Gesture.StateType.Continuing)
1734 if (ScrollingDirection == Direction.Horizontal)
1736 // if vertical shadow is shown, does not scroll.
1737 if (!isOverShootingShadowShown)
1739 ScrollBy(panGesture.Displacement.X, false);
1741 totalDisplacementForPan += panGesture.Displacement.X;
1742 DragOverShootingShadow(totalDisplacementForPan, panGesture.Displacement.X);
1746 // if vertical shadow is shown, does not scroll.
1747 if (!isOverShootingShadowShown)
1749 ScrollBy(panGesture.Displacement.Y, false);
1751 totalDisplacementForPan += panGesture.Displacement.Y;
1752 DragOverShootingShadow(totalDisplacementForPan, panGesture.Displacement.Y);
1754 Debug.WriteLineIf(LayoutDebugScrollableBase, "OnPanGestureDetected Continue totalDisplacementForPan:" + totalDisplacementForPan);
1757 else if (panGesture.State == Gesture.StateType.Finished || panGesture.State == Gesture.StateType.Cancelled)
1759 PlayOverShootingShadowAnimation();
1760 OnScrollDragEnded();
1761 StopScroll(); // Will replace previous animation so will stop existing one.
1763 if (scrollAnimation == null)
1765 scrollAnimation = new Animation();
1766 scrollAnimation.Finished += ScrollAnimationFinished;
1769 float panVelocity = (ScrollingDirection == Direction.Horizontal) ? panGesture.Velocity.X : panGesture.Velocity.Y;
1773 PageSnap(panVelocity);
1777 if (panVelocity == 0)
1779 float currentScrollPosition = (ScrollingDirection == Direction.Horizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y);
1780 scrollAnimation.DefaultAlphaFunction = new AlphaFunction(AlphaFunction.BuiltinFunctions.Linear);
1781 scrollAnimation.Duration = 0;
1782 scrollAnimation.AnimateTo(ContentContainer, (ScrollingDirection == Direction.Horizontal) ? "PositionX" : "PositionY", currentScrollPosition);
1783 scrollAnimation.Play();
1787 Decelerating(panVelocity, scrollAnimation);
1791 totalDisplacementForPan = 0;
1793 readyToNotice = true;
1794 OnScrollAnimationStarted();
1799 internal void BaseRemove(View view)
1804 internal override bool OnAccessibilityPan(PanGesture gestures)
1806 if (SnapToPage && scrollAnimation != null && scrollAnimation.State == Animation.States.Playing)
1811 OnPanGesture(gestures);
1815 private float CustomScrollAlphaFunction(float progress)
1817 if (panAnimationDelta == 0)
1823 // Parameter "progress" is normalized value. We need to multiply target duration to calculate distance.
1824 // Can get real distance using equation of deceleration (check Decelerating function)
1825 // After get real distance, normalize it
1826 float realDuration = progress * panAnimationDuration;
1827 float realDistance = velocityOfLastPan * ((float)Math.Pow(decelerationRate, realDuration) - 1) / logValueOfDeceleration;
1828 float result = Math.Min(realDistance / Math.Abs(panAnimationDelta), 1.0f);
1830 // This is hot-fix for if the velocity has very small value, result is not updated even progress done.
1831 if (progress > 0.99) result = 1.0f;
1838 /// you can override it to custom your decelerating
1840 /// <param name="velocity">Velocity of current pan.</param>
1841 /// <param name="animation">Scroll animation.</param>
1842 [EditorBrowsable(EditorBrowsableState.Never)]
1843 protected virtual void Decelerating(float velocity, Animation animation)
1845 if (animation == null) throw new ArgumentNullException(nameof(animation));
1846 // Decelerating using deceleration equation ===========
1848 // V : velocity (pixel per millisecond)
1849 // V0 : initial velocity
1850 // d : deceleration rate,
1852 // X : final position after decelerating
1853 // log : natural logarithm
1855 // V(t) = V0 * d pow t;
1856 // X(t) = V0 * (d pow t - 1) / log d; <-- Integrate the velocity function
1857 // X(∞) = V0 * d / (1 - d); <-- Result using infinite T can be final position because T is tending to infinity.
1859 // Because of final T is tending to infinity, we should use threshold value to finish.
1860 // Final T = log(-threshold * log d / |V0| ) / log d;
1862 velocityOfLastPan = Math.Abs(velocity);
1864 float currentScrollPosition = -(ScrollingDirection == Direction.Horizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y);
1865 panAnimationDelta = (velocityOfLastPan * decelerationRate) / (1 - decelerationRate);
1866 panAnimationDelta = velocity > 0 ? -panAnimationDelta : panAnimationDelta;
1868 float destination = -(panAnimationDelta + currentScrollPosition);
1869 float adjustDestination = AdjustTargetPositionOfScrollAnimation(destination);
1870 float maxPosition = ScrollAvailableArea != null ? ScrollAvailableArea.Y : maxScrollDistance;
1871 float minPosition = ScrollAvailableArea != null ? ScrollAvailableArea.X : 0;
1873 if (destination < -maxPosition || destination > minPosition)
1875 panAnimationDelta = velocity > 0 ? (currentScrollPosition - minPosition) : (maxPosition - currentScrollPosition);
1876 destination = velocity > 0 ? minPosition : -maxPosition;
1878 if (panAnimationDelta == 0)
1880 panAnimationDuration = 0.0f;
1884 panAnimationDuration = (float)Math.Log((panAnimationDelta * logValueOfDeceleration / velocityOfLastPan + 1), decelerationRate);
1887 Debug.WriteLineIf(LayoutDebugScrollableBase, "\n" +
1888 "OverRange======================= \n" +
1889 "[decelerationRate] " + decelerationRate + "\n" +
1890 "[logValueOfDeceleration] " + logValueOfDeceleration + "\n" +
1891 "[Velocity] " + velocityOfLastPan + "\n" +
1892 "[CurrentPosition] " + currentScrollPosition + "\n" +
1893 "[CandidateDelta] " + panAnimationDelta + "\n" +
1894 "[Destination] " + destination + "\n" +
1895 "[Duration] " + panAnimationDuration + "\n" +
1896 "================================ \n"
1901 panAnimationDuration = (float)Math.Log(-DecelerationThreshold * logValueOfDeceleration / velocityOfLastPan) / logValueOfDeceleration;
1903 if (adjustDestination != destination)
1905 destination = adjustDestination;
1906 panAnimationDelta = destination + currentScrollPosition;
1907 velocityOfLastPan = Math.Abs(panAnimationDelta * logValueOfDeceleration / ((float)Math.Pow(decelerationRate, panAnimationDuration) - 1));
1908 panAnimationDuration = (float)Math.Log(-DecelerationThreshold * logValueOfDeceleration / velocityOfLastPan) / logValueOfDeceleration;
1911 Debug.WriteLineIf(LayoutDebugScrollableBase, "\n" +
1912 "================================ \n" +
1913 "[decelerationRate] " + decelerationRate + "\n" +
1914 "[logValueOfDeceleration] " + logValueOfDeceleration + "\n" +
1915 "[Velocity] " + velocityOfLastPan + "\n" +
1916 "[CurrentPosition] " + currentScrollPosition + "\n" +
1917 "[CandidateDelta] " + panAnimationDelta + "\n" +
1918 "[Destination] " + destination + "\n" +
1919 "[Duration] " + panAnimationDuration + "\n" +
1920 "================================ \n"
1924 finalTargetPosition = destination;
1926 customScrollAlphaFunction = new UserAlphaFunctionDelegate(CustomScrollAlphaFunction);
1927 animation.DefaultAlphaFunction = new AlphaFunction(customScrollAlphaFunction);
1928 GC.KeepAlive(customScrollAlphaFunction);
1929 animation.Duration = (int)panAnimationDuration;
1930 animation.AnimateTo(ContentContainer, (ScrollingDirection == Direction.Horizontal) ? "PositionX" : "PositionY", destination);
1934 private void ScrollAnimationFinished(object sender, EventArgs e)
1936 OnScrollAnimationEnded();
1940 /// Adjust scrolling position by own scrolling rules.
1941 /// Override this function when developer wants to change destination of flicking.(e.g. always snap to center of item)
1943 /// This may be public opened in tizen_6.0 after ACR done. Before ACR, need to be hidden as inhouse API
1944 [EditorBrowsable(EditorBrowsableState.Never)]
1945 protected virtual float AdjustTargetPositionOfScrollAnimation(float position)
1951 /// Scroll position given to ScrollTo.
1952 /// This is the position in the opposite direction to the position of ContentContainer.
1954 /// <since_tizen> 8 </since_tizen>
1955 public Position ScrollPosition
1959 return new Position(-ContentContainer.Position);
1964 /// Current scroll position in the middle of ScrollTo animation.
1965 /// This is the position in the opposite direction to the current position of ContentContainer.
1967 /// <since_tizen> 8 </since_tizen>
1968 public Position ScrollCurrentPosition
1972 return new Position(-ContentContainer.CurrentPosition);
1977 /// Remove all children in ContentContainer.
1979 /// <param name="dispose">If true, removed child is disposed.</param>
1980 [EditorBrowsable(EditorBrowsableState.Never)]
1981 public void RemoveAllChildren(bool dispose = false)
1983 RecursiveRemoveChildren(ContentContainer, dispose);
1986 private void RecursiveRemoveChildren(View parent, bool dispose)
1992 int maxChild = (int)parent.GetChildCount();
1993 for (int i = maxChild - 1; i >= 0; --i)
1995 View child = parent.GetChildAt((uint)i);
2000 RecursiveRemoveChildren(child, dispose);
2001 parent.Remove(child);
2009 internal bool IsChildNearlyVisble(View child, float offset = 0)
2011 if (ScreenPosition.X - offset < child.ScreenPosition.X + child.SizeWidth &&
2012 ScreenPosition.X + SizeWidth + offset > child.ScreenPosition.X &&
2013 ScreenPosition.Y - offset < child.ScreenPosition.Y + child.SizeHeight &&
2014 ScreenPosition.Y + SizeHeight + offset > child.ScreenPosition.Y)
2025 [EditorBrowsable(EditorBrowsableState.Never)]
2026 public override View GetNextFocusableView(View currentFocusedView, View.FocusDirection direction, bool loopEnabled)
2028 bool isHorizontal = (ScrollingDirection == Direction.Horizontal);
2029 float targetPosition = -(ScrollingDirection == Direction.Horizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y);
2030 float stepDistance = (stepScrollDistance != 0 ? stepScrollDistance : (isHorizontal ? Size.Width * 0.25f : Size.Height * 0.25f));
2032 bool forward = ((isHorizontal && direction == View.FocusDirection.Right) ||
2033 (!isHorizontal && direction == View.FocusDirection.Down) ||
2034 (direction == View.FocusDirection.Clockwise));
2035 bool backward = ((isHorizontal && direction == View.FocusDirection.Left) ||
2036 (!isHorizontal && direction == View.FocusDirection.Up) ||
2037 (direction == View.FocusDirection.CounterClockwise));
2039 View nextFocusedView = FocusManager.Instance.GetNearestFocusableActor(this, currentFocusedView, direction);
2041 // Move out focus from ScrollableBase.
2042 // FIXME: Forward, Backward is unimplemented other components.
2043 if (direction == View.FocusDirection.Forward ||
2044 direction == View.FocusDirection.Backward ||
2045 (nextFocusedView == null &&
2046 ((forward && maxScrollDistance - targetPosition < 0.1f) ||
2047 (backward && targetPosition < 0.1f))))
2049 var next = FocusManager.Instance.GetNearestFocusableActor(this.Parent, this, direction);
2050 Debug.WriteLineIf(focusDebugScrollableBase, $"Focus move [{direction}] out from ScrollableBase! Next focus target {next}:{next?.ID}");
2054 if (focusDebugScrollableBase)
2056 global::System.Text.StringBuilder debugMessage = new global::System.Text.StringBuilder("=========================================================\n");
2057 debugMessage.Append($"GetNextFocusableView On: {this}:{this.ID}\n");
2058 debugMessage.Append($"----------------Current: {currentFocusedView}:{currentFocusedView?.ID}\n");
2059 debugMessage.Append($"-------------------Next: {nextFocusedView}:{nextFocusedView?.ID}\n");
2060 debugMessage.Append($"--------------Direction: {direction}\n");
2061 debugMessage.Append("=========================================================");
2062 Debug.WriteLineIf(focusDebugScrollableBase, debugMessage);
2065 if (nextFocusedView != null)
2067 if (null != FindDescendantByID(nextFocusedView.ID))
2069 if (IsChildNearlyVisble(nextFocusedView, stepDistance) == true)
2071 ScrollToChild(nextFocusedView, true);
2072 return nextFocusedView;
2077 if (forward || backward)
2079 // Fallback to current focus or scrollableBase till next focus visible in scrollable.
2080 if (null != currentFocusedView && null != FindDescendantByID(currentFocusedView.ID))
2082 nextFocusedView = currentFocusedView;
2086 Debug.WriteLineIf(focusDebugScrollableBase, "current focus view is not decendant. return ScrollableBase!");
2092 targetPosition += stepDistance;
2093 targetPosition = targetPosition > maxScrollDistance ? maxScrollDistance : targetPosition;
2098 targetPosition -= stepDistance;
2099 targetPosition = targetPosition < 0 ? 0 : targetPosition;
2102 ScrollTo(targetPosition, true);
2104 Debug.WriteLineIf(focusDebugScrollableBase, $"ScrollTo :({targetPosition})");
2107 Debug.WriteLineIf(focusDebugScrollableBase, $"return end : {nextFocusedView}:{nextFocusedView?.ID}");
2108 return nextFocusedView;
2112 [EditorBrowsable(EditorBrowsableState.Never)]
2113 protected override bool AccessibilityScrollToChild(View child)
2120 if (ScrollingDirection == Direction.Horizontal)
2122 if (child.ScreenPosition.X + child.Size.Width <= this.ScreenPosition.X)
2126 PageSnap(PageFlickThreshold + 1);
2130 ScrollTo((float)(child.ScreenPosition.X - ContentContainer.ScreenPosition.X), false);
2133 else if (child.ScreenPosition.X >= this.ScreenPosition.X + this.Size.Width)
2137 PageSnap(-(PageFlickThreshold + 1));
2141 ScrollTo((float)(child.ScreenPosition.X + child.Size.Width - ContentContainer.ScreenPosition.X - this.Size.Width), false);
2147 if (child.ScreenPosition.Y + child.Size.Height <= this.ScreenPosition.Y)
2151 PageSnap(PageFlickThreshold + 1);
2155 ScrollTo((float)(child.ScreenPosition.Y - ContentContainer.ScreenPosition.Y), false);
2158 else if (child.ScreenPosition.Y >= this.ScreenPosition.Y + this.Size.Height)
2162 PageSnap(-(PageFlickThreshold + 1));
2166 ScrollTo((float)(child.ScreenPosition.Y + child.Size.Height - ContentContainer.ScreenPosition.Y - this.Size.Height), false);
2175 [EditorBrowsable(EditorBrowsableState.Never)]
2176 public override bool OnWheel(Wheel wheel)
2183 float currentScrollPosition = -(ScrollingDirection == Direction.Horizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y);
2184 ScrollTo(currentScrollPosition + (wheelScrollDistance * wheel.Z), false);
2189 private bool OnWheelEvent(object o, WheelEventArgs e)
2191 return OnWheel(e?.Wheel);