1 /* Copyright (c) 2020 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 public class ScrollEventArgs : EventArgs
32 private Position position;
35 /// Default constructor.
37 /// <param name="position">Current scroll position</param>
38 /// <since_tizen> 8 </since_tizen>
39 public ScrollEventArgs(Position position)
41 this.position = position;
45 /// Current position of ContentContainer.
47 /// <since_tizen> 8 </since_tizen>
48 public Position Position
58 /// This class provides a View that can scroll a single View with a layout. This View can be a nest of Views.
60 /// <since_tizen> 8 </since_tizen>
61 public class ScrollableBase : Control
63 static bool LayoutDebugScrollableBase = false; // Debug flag
64 private Direction mScrollingDirection = Direction.Vertical;
65 private bool mScrollEnabled = true;
66 private int mScrollDuration = 125;
67 private int mPageWidth = 0;
68 private float mPageFlickThreshold = 0.4f;
69 private float mScrollingEventThreshold = 0.00001f;
71 private class ScrollableBaseCustomLayout : LayoutGroup
73 protected override void OnMeasure(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
75 Extents padding = Padding;
76 float totalHeight = padding.Top + padding.Bottom;
77 float totalWidth = padding.Start + padding.End;
79 MeasuredSize.StateType childWidthState = MeasuredSize.StateType.MeasuredSizeOK;
80 MeasuredSize.StateType childHeightState = MeasuredSize.StateType.MeasuredSizeOK;
82 Direction scrollingDirection = Direction.Vertical;
83 ScrollableBase scrollableBase = this.Owner as ScrollableBase;
86 scrollingDirection = scrollableBase.ScrollingDirection;
89 // measure child, should be a single scrolling child
90 foreach (LayoutItem childLayout in LayoutChildren)
92 if (childLayout != null)
95 // Use an Unspecified MeasureSpecification mode so scrolling child is not restricted to it's parents size in Height (for vertical scrolling)
96 // or Width for horizontal scrolling
97 MeasureSpecification unrestrictedMeasureSpec = new MeasureSpecification(heightMeasureSpec.Size, MeasureSpecification.ModeType.Unspecified);
99 if (scrollingDirection == Direction.Vertical)
101 MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), unrestrictedMeasureSpec, new LayoutLength(0)); // Height unrestricted by parent
105 MeasureChildWithMargins(childLayout, unrestrictedMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0)); // Width unrestricted by parent
108 float childWidth = childLayout.MeasuredWidth.Size.AsDecimal();
109 float childHeight = childLayout.MeasuredHeight.Size.AsDecimal();
111 // Determine the width and height needed by the children using their given position and size.
112 // Children could overlap so find the left most and right most child.
113 Position2D childPosition = childLayout.Owner.Position2D;
114 float childLeft = childPosition.X;
115 float childTop = childPosition.Y;
117 // Store current width and height needed to contain all children.
118 Extents childMargin = childLayout.Margin;
119 totalWidth = childWidth + childMargin.Start + childMargin.End;
120 totalHeight = childHeight + childMargin.Top + childMargin.Bottom;
122 if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
124 childWidthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
126 if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
128 childHeightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
134 MeasuredSize widthSizeAndState = ResolveSizeAndState(new LayoutLength(totalWidth + Padding.Start + Padding.End), widthMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
135 MeasuredSize heightSizeAndState = ResolveSizeAndState(new LayoutLength(totalHeight + Padding.Top + Padding.Bottom), heightMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
136 totalWidth = widthSizeAndState.Size.AsDecimal();
137 totalHeight = heightSizeAndState.Size.AsDecimal();
139 // Ensure layout respects it's given minimum size
140 totalWidth = Math.Max(totalWidth, SuggestedMinimumWidth.AsDecimal());
141 totalHeight = Math.Max(totalHeight, SuggestedMinimumHeight.AsDecimal());
143 widthSizeAndState.State = childWidthState;
144 heightSizeAndState.State = childHeightState;
146 SetMeasuredDimensions(ResolveSizeAndState(new LayoutLength(totalWidth + Padding.Start + Padding.End), widthMeasureSpec, childWidthState),
147 ResolveSizeAndState(new LayoutLength(totalHeight + Padding.Top + Padding.Bottom), heightMeasureSpec, childHeightState));
149 // Size of ScrollableBase is changed. Change Page width too.
150 scrollableBase.mPageWidth = (int)MeasuredWidth.Size.AsRoundedValue();
151 scrollableBase.OnScrollingChildRelayout(null , null);
154 protected override void OnLayout(bool changed, LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
156 foreach (LayoutItem childLayout in LayoutChildren)
158 if (childLayout != null)
160 LayoutLength childWidth = childLayout.MeasuredWidth.Size;
161 LayoutLength childHeight = childLayout.MeasuredHeight.Size;
163 Position2D childPosition = childLayout.Owner.Position2D;
164 Extents padding = Padding;
165 Extents childMargin = childLayout.Margin;
167 LayoutLength childLeft = new LayoutLength(childPosition.X + childMargin.Start + padding.Start);
168 LayoutLength childTop = new LayoutLength(childPosition.Y + childMargin.Top + padding.Top);
170 childLayout.Layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
174 } // ScrollableBaseCustomLayout
177 /// The direction axis to scroll.
179 /// <since_tizen> 8 </since_tizen>
180 public enum Direction
185 /// <since_tizen> 8 </since_tizen>
191 /// <since_tizen> 8 </since_tizen>
196 /// Scrolling direction mode.
197 /// Default is Vertical scrolling.
199 /// <since_tizen> 8 </since_tizen>
200 public Direction ScrollingDirection
204 return mScrollingDirection;
208 if (value != mScrollingDirection)
210 mScrollingDirection = value;
211 mPanGestureDetector.RemoveDirection(value == Direction.Horizontal ?
212 PanGestureDetector.DirectionVertical : PanGestureDetector.DirectionHorizontal);
213 mPanGestureDetector.AddDirection(value == Direction.Horizontal ?
214 PanGestureDetector.DirectionHorizontal : PanGestureDetector.DirectionVertical);
216 ContentContainer.WidthSpecification = mScrollingDirection == Direction.Vertical ?
217 LayoutParamPolicies.MatchParent : LayoutParamPolicies.WrapContent;
218 ContentContainer.HeightSpecification = mScrollingDirection == Direction.Vertical ?
219 LayoutParamPolicies.WrapContent : LayoutParamPolicies.MatchParent;
225 /// Enable or disable scrolling.
227 /// <since_tizen> 8 </since_tizen>
228 public bool ScrollEnabled
232 return mScrollEnabled;
236 if (value != mScrollEnabled)
238 mScrollEnabled = value;
241 mPanGestureDetector.Detected += OnPanGestureDetected;
245 mPanGestureDetector.Detected -= OnPanGestureDetected;
252 /// Pages mode, enables moving to the next or return to current page depending on pan displacement.
253 /// Default is false.
255 /// <since_tizen> 8 </since_tizen>
256 public bool SnapToPage { set; get; } = false;
259 /// Get current page.
260 /// Working property with SnapToPage property.
262 /// <since_tizen> 8 </since_tizen>
263 public int CurrentPage { get; private set; } = 0;
266 /// Duration of scroll animation.
267 /// Default value is 125ms.
269 /// <since_tizen> 8 </since_tizen>
270 public int ScrollDuration
274 mScrollDuration = value >= 0 ? value : mScrollDuration;
278 return mScrollDuration;
283 /// Scroll Available area.
285 /// <since_tizen> 8 </since_tizen>
286 public Vector2 ScrollAvailableArea { set; get; }
289 /// An event emitted when user starts dragging ScrollableBase, user can subscribe or unsubscribe to this event handler.<br />
291 /// <since_tizen> 8 </since_tizen>
292 public event EventHandler<ScrollEventArgs> ScrollDragStarted;
295 /// An event emitted when user stops dragging ScrollableBase, user can subscribe or unsubscribe to this event handler.<br />
297 /// <since_tizen> 8 </since_tizen>
298 public event EventHandler<ScrollEventArgs> ScrollDragEnded;
302 /// An event emitted when the scrolling slide animation starts, user can subscribe or unsubscribe to this event handler.<br />
304 /// <since_tizen> 8 </since_tizen>
305 public event EventHandler<ScrollEventArgs> ScrollAnimationStarted;
308 /// An event emitted when the scrolling slide animation ends, user can subscribe or unsubscribe to this event handler.<br />
310 /// <since_tizen> 8 </since_tizen>
311 public event EventHandler<ScrollEventArgs> ScrollAnimationEnded;
315 /// An event emitted when scrolling, user can subscribe or unsubscribe to this event handler.<br />
317 /// <since_tizen> 8 </since_tizen>
318 public event EventHandler<ScrollEventArgs> Scrolling;
322 /// Scrollbar for ScrollableBase.
324 /// <since_tizen> 8 </since_tizen>
325 public ScrollbarBase Scrollbar
335 scrollBar.Unparent();
339 scrollBar.Name = "ScrollBar";
356 /// Always hide Scrollbar.
358 /// <since_tizen> 8 </since_tizen>
359 public bool HideScrollbar
363 return hideScrollbar;
367 hideScrollbar = value;
384 /// Container which has content of ScrollableBase.
386 /// <since_tizen> 8 </since_tizen>
387 public View ContentContainer { get; private set; }
390 /// Set the layout on this View. Replaces any existing Layout.
392 /// <since_tizen> 8 </since_tizen>
393 public new LayoutItem Layout
397 return ContentContainer.Layout;
401 ContentContainer.Layout = value;
402 if (ContentContainer.Layout != null)
404 ContentContainer.Layout.SetPositionByLayout = false;
410 /// List of children of Container.
412 /// <since_tizen> 8 </since_tizen>
413 public new List<View> Children
417 return ContentContainer.Children;
422 /// Deceleration rate of scrolling by finger.
423 /// Rate should be bigger than 0 and smaller than 1.
424 /// Default value is 0.998f;
426 /// <since_tizen> 8 </since_tizen>
427 public float DecelerationRate
431 return decelerationRate;
435 decelerationRate = (value < 1 && value > 0) ? value : decelerationRate;
436 logValueOfDeceleration = (float)Math.Log(value);
441 /// Threashold not to go infinit at the end of scrolling animation.
443 [EditorBrowsable(EditorBrowsableState.Never)]
444 public float DecelerationThreshold { get; set; } = 0.1f;
447 /// Scrolling event will be thrown when this amount of scroll positino is changed.
449 [EditorBrowsable(EditorBrowsableState.Never)]
450 public float ScrollingEventThreshold
454 return mScrollingEventThreshold;
458 if (mScrollingEventThreshold != value && value > 0)
460 ContentContainer.RemovePropertyNotification(propertyNotification);
461 propertyNotification = ContentContainer.AddPropertyNotification("position", PropertyCondition.Step(value));
462 propertyNotification.Notified += OnPropertyChanged;
463 mScrollingEventThreshold = value;
470 /// Page will be changed when velocity of panning is over threshold.
471 /// The unit of threshold is pixel per milisec.
473 /// <since_tizen> 8 </since_tizen>
474 public float PageFlickThreshold
478 return mPageFlickThreshold;
482 mPageFlickThreshold = value >= 0f ? value : mPageFlickThreshold;
487 /// Alphafunction for scroll animation.
489 [EditorBrowsable(EditorBrowsableState.Never)]
490 public AlphaFunction ScrollAlphaFunction { get; set; } = new AlphaFunction(AlphaFunction.BuiltinFunctions.Linear);
492 private bool hideScrollbar = true;
493 private float maxScrollDistance;
494 private float childTargetPosition = 0.0f;
495 private PanGestureDetector mPanGestureDetector;
496 private View mInterruptTouchingChild;
497 private ScrollbarBase scrollBar;
498 private bool scrolling = false;
499 private float ratioOfScreenWidthToCompleteScroll = 0.5f;
500 private float totalDisplacementForPan = 0.0f;
501 private Size previousContainerSize = new Size();
502 private Size previousSize = new Size();
503 private PropertyNotification propertyNotification;
504 private float noticeAnimationEndBeforePosition = 0.0f;
505 private bool readyToNotice = false;
508 /// Notice before animation is finished.
510 [EditorBrowsable(EditorBrowsableState.Never)]
511 // Let's consider more whether this needs to be set as protected.
512 public float NoticeAnimationEndBeforePosition { get => noticeAnimationEndBeforePosition; set => noticeAnimationEndBeforePosition = value; }
514 // Let's consider more whether this needs to be set as protected.
515 private float finalTargetPosition;
517 private Animation scrollAnimation;
518 // Declare user alpha function delegate
519 [UnmanagedFunctionPointer(CallingConvention.StdCall)]
520 private delegate float UserAlphaFunctionDelegate(float progress);
521 private UserAlphaFunctionDelegate customScrollAlphaFunction;
522 private float velocityOfLastPan = 0.0f;
523 private float panAnimationDuration = 0.0f;
524 private float panAnimationDelta = 0.0f;
525 private float logValueOfDeceleration = 0.0f;
526 private float decelerationRate = 0.0f;
529 /// Default Constructor
531 /// <since_tizen> 8 </since_tizen>
532 public ScrollableBase() : base()
534 DecelerationRate = 0.998f;
536 base.Layout = new ScrollableBaseCustomLayout();
537 mPanGestureDetector = new PanGestureDetector();
538 mPanGestureDetector.Attach(this);
539 mPanGestureDetector.AddDirection(PanGestureDetector.DirectionVertical);
540 mPanGestureDetector.Detected += OnPanGestureDetected;
542 ClippingMode = ClippingModeType.ClipChildren;
544 //Default Scrolling child
545 ContentContainer = new View()
547 WidthSpecification = ScrollingDirection == Direction.Vertical ? LayoutParamPolicies.MatchParent : LayoutParamPolicies.WrapContent,
548 HeightSpecification = ScrollingDirection == Direction.Vertical ? LayoutParamPolicies.WrapContent : LayoutParamPolicies.MatchParent,
549 Layout = new AbsoluteLayout() { SetPositionByLayout = false },
551 ContentContainer.Relayout += OnScrollingChildRelayout;
552 propertyNotification = ContentContainer.AddPropertyNotification("position", PropertyCondition.Step(mScrollingEventThreshold));
553 propertyNotification.Notified += OnPropertyChanged;
554 base.Add(ContentContainer);
556 //Interrupt touching when panning is started
557 mInterruptTouchingChild = new View()
559 Size = new Size(Window.Instance.WindowSize),
560 BackgroundColor = Color.Transparent,
562 mInterruptTouchingChild.TouchEvent += OnIterruptTouchingChildTouched;
563 Scrollbar = new Scrollbar();
565 AccessibilityManager.Instance.SetAccessibilityAttribute(this, AccessibilityManager.AccessibilityAttribute.Trait, "ScrollableBase");
568 private bool OnIterruptTouchingChildTouched(object source, View.TouchEventArgs args)
570 if (args.Touch.GetState(0) == PointStateType.Down)
572 if (scrolling && !SnapToPage)
580 private void OnPropertyChanged(object source, PropertyNotification.NotifyEventArgs args)
586 /// Called after a child has been added to the owning view.
588 /// <param name="view">The child which has been added.</param>
589 /// <since_tizen> 8 </since_tizen>
590 public override void Add(View view)
592 ContentContainer.Add(view);
596 /// Called after a child has been removed from the owning view.
598 /// <param name="view">The child which has been removed.</param>
599 /// <since_tizen> 8 </since_tizen>
600 public override void Remove(View view)
602 if (SnapToPage && CurrentPage == Children.IndexOf(view) && CurrentPage == Children.Count - 1)
604 // Target View is current page and also last child.
605 // CurrentPage should be changed to previous page.
606 CurrentPage = Math.Max(0, CurrentPage - 1);
607 ScrollToIndex(CurrentPage);
610 ContentContainer.Remove(view);
613 private void OnScrollingChildRelayout(object source, EventArgs args)
615 // Size is changed. Calculate maxScrollDistance.
616 bool isSizeChanged = previousContainerSize.Width != ContentContainer.Size.Width || previousContainerSize.Height != ContentContainer.Size.Height
617 || previousSize.Width != Size.Width || previousSize.Height != Size.Height;
621 maxScrollDistance = CalculateMaximumScrollDistance();
625 previousContainerSize = ContentContainer.Size;
630 /// The composition of a Scrollbar can vary depending on how you use ScrollableBase.
631 /// Set the composition that will go into the ScrollableBase according to your ScrollableBase.
633 /// <since_tizen> 8 </since_tizen>
634 [EditorBrowsable(EditorBrowsableState.Never)]
635 protected virtual void SetScrollbar()
639 bool isHorizontal = ScrollingDirection == Direction.Horizontal;
640 float contentLength = isHorizontal ? ContentContainer.Size.Width : ContentContainer.Size.Height;
641 float viewportLength = isHorizontal ? Size.Width : Size.Height;
642 float currentPosition = isHorizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y;
643 Scrollbar.Initialize(contentLength, viewportLength, currentPosition, isHorizontal);
648 /// Scrolls to the item at the specified index.
650 /// <param name="index">Index of item.</param>
651 /// <since_tizen> 8 </since_tizen>
652 public void ScrollToIndex(int index)
654 if (ContentContainer.ChildCount - 1 < index || index < 0)
664 float targetPosition = Math.Min(ScrollingDirection == Direction.Vertical ? Children[index].Position.Y : Children[index].Position.X, maxScrollDistance);
665 AnimateChildTo(ScrollDuration, -targetPosition);
668 private void OnScrollDragStarted()
670 ScrollEventArgs eventArgs = new ScrollEventArgs(ContentContainer.CurrentPosition);
671 ScrollDragStarted?.Invoke(this, eventArgs);
674 private void OnScrollDragEnded()
676 ScrollEventArgs eventArgs = new ScrollEventArgs(ContentContainer.CurrentPosition);
677 ScrollDragEnded?.Invoke(this, eventArgs);
680 private void OnScrollAnimationStarted()
682 ScrollEventArgs eventArgs = new ScrollEventArgs(ContentContainer.CurrentPosition);
683 ScrollAnimationStarted?.Invoke(this, eventArgs);
686 private void OnScrollAnimationEnded()
689 base.Remove(mInterruptTouchingChild);
691 ScrollEventArgs eventArgs = new ScrollEventArgs(ContentContainer.CurrentPosition);
692 ScrollAnimationEnded?.Invoke(this, eventArgs);
695 private void OnScroll()
697 ScrollEventArgs eventArgs = new ScrollEventArgs(ContentContainer.CurrentPosition);
698 Scrolling?.Invoke(this, eventArgs);
700 bool isHorizontal = ScrollingDirection == Direction.Horizontal;
701 float contentLength = isHorizontal ? ContentContainer.Size.Width : ContentContainer.Size.Height;
702 float currentPosition = isHorizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y;
704 scrollBar.Update(contentLength, Math.Abs(currentPosition));
705 CheckPreReachedTargetPosition();
708 private void CheckPreReachedTargetPosition()
710 // Check whether we reached pre-reached target position
712 ContentContainer.CurrentPosition.Y <= finalTargetPosition + NoticeAnimationEndBeforePosition &&
713 ContentContainer.CurrentPosition.Y >= finalTargetPosition - NoticeAnimationEndBeforePosition)
716 readyToNotice = false;
717 OnPreReachedTargetPosition(finalTargetPosition);
722 /// This helps developer who wants to know before scroll is reaching target position.
724 /// <param name="targetPosition">Index of item.</param>
725 /// This may be public opened in tizen_6.0 after ACR done. Before ACR, need to be hidden as inhouse API
726 [EditorBrowsable(EditorBrowsableState.Never)]
727 protected virtual void OnPreReachedTargetPosition(float targetPosition)
732 private void StopScroll()
734 if (scrollAnimation != null)
736 if (scrollAnimation.State == Animation.States.Playing)
738 Debug.WriteLineIf(LayoutDebugScrollableBase, "StopScroll Animation Playing");
739 scrollAnimation.Stop(Animation.EndActions.Cancel);
740 OnScrollAnimationEnded();
742 scrollAnimation.Clear();
746 private void AnimateChildTo(int duration, float axisPosition)
748 Debug.WriteLineIf(LayoutDebugScrollableBase, "AnimationTo Animation Duration:" + duration + " Destination:" + axisPosition);
749 finalTargetPosition = axisPosition;
751 StopScroll(); // Will replace previous animation so will stop existing one.
753 if (scrollAnimation == null)
755 scrollAnimation = new Animation();
756 scrollAnimation.Finished += ScrollAnimationFinished;
759 scrollAnimation.Duration = duration;
760 scrollAnimation.DefaultAlphaFunction = new AlphaFunction(AlphaFunction.BuiltinFunctions.EaseOutSquare);
761 scrollAnimation.AnimateTo(ContentContainer, (ScrollingDirection == Direction.Horizontal) ? "PositionX" : "PositionY", axisPosition, ScrollAlphaFunction);
763 OnScrollAnimationStarted();
764 scrollAnimation.Play();
768 /// Scroll to specific position with or without animation.
770 /// <param name="position">Destination.</param>
771 /// <param name="animate">Scroll with or without animation</param>
772 /// <since_tizen> 8 </since_tizen>
773 public void ScrollTo(float position, bool animate)
775 float currentPositionX = ContentContainer.CurrentPosition.X != 0 ? ContentContainer.CurrentPosition.X : ContentContainer.Position.X;
776 float currentPositionY = ContentContainer.CurrentPosition.Y != 0 ? ContentContainer.CurrentPosition.Y : ContentContainer.Position.Y;
777 float delta = ScrollingDirection == Direction.Horizontal ? currentPositionX : currentPositionY;
778 // The argument position is the new pan position. So the new position of ScrollableBase becomes (-position).
779 // To move ScrollableBase's position to (-position), it moves by (-position - currentPosition).
780 delta = -position - delta;
782 ScrollBy(delta, animate);
785 private float BoundScrollPosition(float targetPosition)
787 if (ScrollAvailableArea != null)
789 float minScrollPosition = ScrollAvailableArea.X;
790 float maxScrollPosition = ScrollAvailableArea.Y;
792 targetPosition = Math.Min(-minScrollPosition, targetPosition);
793 targetPosition = Math.Max(-maxScrollPosition, targetPosition);
797 targetPosition = Math.Min(0, targetPosition);
798 targetPosition = Math.Max(-maxScrollDistance, targetPosition);
801 return targetPosition;
804 private void ScrollBy(float displacement, bool animate)
806 if (GetChildCount() == 0 || maxScrollDistance < 0)
811 float childCurrentPosition = (ScrollingDirection == Direction.Horizontal) ? ContentContainer.PositionX : ContentContainer.PositionY;
813 Debug.WriteLineIf(LayoutDebugScrollableBase, "ScrollBy childCurrentPosition:" + childCurrentPosition +
814 " displacement:" + displacement,
815 " maxScrollDistance:" + maxScrollDistance);
817 childTargetPosition = childCurrentPosition + displacement; // child current position + gesture displacement
820 Debug.WriteLineIf(LayoutDebugScrollableBase, "ScrollBy currentAxisPosition:" + childCurrentPosition + "childTargetPosition:" + childTargetPosition);
824 // Calculate scroll animaton duration
825 float scrollDistance = Math.Abs(displacement);
826 readyToNotice = true;
828 AnimateChildTo(ScrollDuration, BoundScrollPosition(AdjustTargetPositionOfScrollAnimation(BoundScrollPosition(childTargetPosition))));
832 finalTargetPosition = BoundScrollPosition(childTargetPosition);
834 // Set position of scrolling child without an animation
835 if (ScrollingDirection == Direction.Horizontal)
837 ContentContainer.PositionX = finalTargetPosition;
841 ContentContainer.PositionY = finalTargetPosition;
848 /// you can override it to clean-up your own resources.
850 /// <param name="type">DisposeTypes</param>
851 /// This will be public opened in tizen_5.5 after ACR done. Before ACR, need to be hidden as inhouse API.
852 [EditorBrowsable(EditorBrowsableState.Never)]
853 protected override void Dispose(DisposeTypes type)
860 if (type == DisposeTypes.Explicit)
864 if (mPanGestureDetector != null)
866 mPanGestureDetector.Detected -= OnPanGestureDetected;
867 mPanGestureDetector.Dispose();
868 mPanGestureDetector = null;
871 propertyNotification.Dispose();
876 private float CalculateMaximumScrollDistance()
878 float scrollingChildLength = 0;
879 float scrollerLength = 0;
880 if (ScrollingDirection == Direction.Horizontal)
882 Debug.WriteLineIf(LayoutDebugScrollableBase, "Horizontal");
884 scrollingChildLength = ContentContainer.Size.Width;
885 scrollerLength = Size.Width;
889 Debug.WriteLineIf(LayoutDebugScrollableBase, "Vertical");
890 scrollingChildLength = ContentContainer.Size.Height;
891 scrollerLength = Size.Height;
894 Debug.WriteLineIf(LayoutDebugScrollableBase, "ScrollBy maxScrollDistance:" + (scrollingChildLength - scrollerLength) +
895 " parent length:" + scrollerLength +
896 " scrolling child length:" + scrollingChildLength);
898 return Math.Max(scrollingChildLength - scrollerLength, 0);
901 private void PageSnap(float velocity)
903 Debug.WriteLineIf(LayoutDebugScrollableBase, "PageSnap with pan candidate totalDisplacement:" + totalDisplacementForPan +
904 " currentPage[" + CurrentPage + "]");
906 //Increment current page if total displacement enough to warrant a page change.
907 if (Math.Abs(totalDisplacementForPan) > (mPageWidth * ratioOfScreenWidthToCompleteScroll))
909 if (totalDisplacementForPan < 0)
911 CurrentPage = Math.Min(Math.Max(Children.Count - 1, 0), ++CurrentPage);
915 CurrentPage = Math.Max(0, --CurrentPage);
918 else if (Math.Abs(velocity) > PageFlickThreshold)
922 CurrentPage = Math.Min(Math.Max(Children.Count - 1, 0), ++CurrentPage);
926 CurrentPage = Math.Max(0, --CurrentPage);
930 // Animate to new page or reposition to current page
931 float destinationX = -(Children[CurrentPage].Position.X + Children[CurrentPage].CurrentSize.Width / 2 - CurrentSize.Width / 2); // set to middle of current page
932 Debug.WriteLineIf(LayoutDebugScrollableBase, "Snapping to page[" + CurrentPage + "] to:" + destinationX + " from:" + ContentContainer.PositionX);
933 AnimateChildTo(ScrollDuration, destinationX);
936 private void OnPanGestureDetected(object source, PanGestureDetector.DetectedEventArgs e)
938 OnPanGesture(e.PanGesture);
941 private void OnPanGesture(PanGesture panGesture)
943 if (SnapToPage && scrollAnimation != null && scrollAnimation.State == Animation.States.Playing)
948 if (panGesture.State == Gesture.StateType.Started)
950 readyToNotice = false;
951 base.Add(mInterruptTouchingChild);
952 Debug.WriteLineIf(LayoutDebugScrollableBase, "Gesture Start");
953 if (scrolling && !SnapToPage)
957 totalDisplacementForPan = 0.0f;
958 OnScrollDragStarted();
960 else if (panGesture.State == Gesture.StateType.Continuing)
962 if (ScrollingDirection == Direction.Horizontal)
964 ScrollBy(panGesture.Displacement.X, false);
965 totalDisplacementForPan += panGesture.Displacement.X;
969 ScrollBy(panGesture.Displacement.Y, false);
970 totalDisplacementForPan += panGesture.Displacement.Y;
972 Debug.WriteLineIf(LayoutDebugScrollableBase, "OnPanGestureDetected Continue totalDisplacementForPan:" + totalDisplacementForPan);
974 else if (panGesture.State == Gesture.StateType.Finished || panGesture.State == Gesture.StateType.Cancelled)
977 StopScroll(); // Will replace previous animation so will stop existing one.
979 if (scrollAnimation == null)
981 scrollAnimation = new Animation();
982 scrollAnimation.Finished += ScrollAnimationFinished;
985 float panVelocity = (ScrollingDirection == Direction.Horizontal) ? panGesture.Velocity.X : panGesture.Velocity.Y;
989 PageSnap(panVelocity);
993 if (panVelocity == 0)
995 float currentScrollPosition = (ScrollingDirection == Direction.Horizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y);
996 scrollAnimation.DefaultAlphaFunction = new AlphaFunction(AlphaFunction.BuiltinFunctions.Linear);
997 scrollAnimation.Duration = 0;
998 scrollAnimation.AnimateTo(ContentContainer, (ScrollingDirection == Direction.Horizontal) ? "PositionX" : "PositionY", currentScrollPosition);
999 scrollAnimation.Play();
1003 Decelerating(panVelocity, scrollAnimation);
1007 totalDisplacementForPan = 0;
1009 readyToNotice = true;
1010 OnScrollAnimationStarted();
1014 internal override bool OnAccessibilityPan(PanGesture gestures)
1016 if (SnapToPage && scrollAnimation != null && scrollAnimation.State == Animation.States.Playing)
1021 OnPanGesture(gestures);
1025 private float CustomScrollAlphaFunction(float progress)
1027 if (panAnimationDelta == 0)
1033 // Parameter "progress" is normalized value. We need to multiply target duration to calculate distance.
1034 // Can get real distance using equation of deceleration (check Decelerating function)
1035 // After get real distance, normalize it
1036 float realDuration = progress * panAnimationDuration;
1037 float realDistance = velocityOfLastPan * ((float)Math.Pow(decelerationRate, realDuration) - 1) / logValueOfDeceleration;
1038 float result = Math.Min(realDistance / Math.Abs(panAnimationDelta), 1.0f);
1044 /// you can override it to custom your decelerating
1046 /// <param name="velocity">Velocity of current pan.</param>
1047 /// <param name="animation">Scroll animation.</param>
1048 [EditorBrowsable(EditorBrowsableState.Never)]
1049 protected virtual void Decelerating(float velocity, Animation animation)
1051 // Decelerating using deceleration equation ===========
1053 // V : velocity (pixel per milisecond)
1054 // V0 : initial velocity
1055 // d : deceleration rate,
1057 // X : final position after decelerating
1058 // log : natural logarithm
1060 // V(t) = V0 * d pow t;
1061 // X(t) = V0 * (d pow t - 1) / log d; <-- Integrate the velocity function
1062 // X(∞) = V0 * d / (1 - d); <-- Result using inifit T can be final position because T is tending to infinity.
1064 // Because of final T is tending to inifity, we should use threshold value to finish.
1065 // Final T = log(-threshold * log d / |V0| ) / log d;
1067 velocityOfLastPan = Math.Abs(velocity);
1069 float currentScrollPosition = -(ScrollingDirection == Direction.Horizontal ? ContentContainer.CurrentPosition.X : ContentContainer.CurrentPosition.Y);
1070 panAnimationDelta = (velocityOfLastPan * decelerationRate) / (1 - decelerationRate);
1071 panAnimationDelta = velocity > 0 ? -panAnimationDelta : panAnimationDelta;
1073 float destination = -(panAnimationDelta + currentScrollPosition);
1074 float adjustDestination = AdjustTargetPositionOfScrollAnimation(destination);
1075 float maxPosition = ScrollAvailableArea != null ? ScrollAvailableArea.Y : maxScrollDistance;
1076 float minPosition = ScrollAvailableArea != null ? ScrollAvailableArea.X : 0;
1078 if (destination < -maxPosition || destination > minPosition)
1080 panAnimationDelta = velocity > 0 ? (currentScrollPosition - minPosition) : (maxPosition - currentScrollPosition);
1081 destination = velocity > 0 ? minPosition : -maxPosition;
1083 if (panAnimationDelta == 0)
1085 panAnimationDuration = 0.0f;
1089 panAnimationDuration = (float)Math.Log((panAnimationDelta * logValueOfDeceleration / velocityOfLastPan + 1), decelerationRate);
1092 Debug.WriteLineIf(LayoutDebugScrollableBase, "\n" +
1093 "OverRange======================= \n" +
1094 "[decelerationRate] " + decelerationRate + "\n" +
1095 "[logValueOfDeceleration] " + logValueOfDeceleration + "\n" +
1096 "[Velocity] " + velocityOfLastPan + "\n" +
1097 "[CurrentPosition] " + currentScrollPosition + "\n" +
1098 "[CandidateDelta] " + panAnimationDelta + "\n" +
1099 "[Destination] " + destination + "\n" +
1100 "[Duration] " + panAnimationDuration + "\n" +
1101 "================================ \n"
1106 panAnimationDuration = (float)Math.Log(-DecelerationThreshold * logValueOfDeceleration / velocityOfLastPan) / logValueOfDeceleration;
1108 if (adjustDestination != destination)
1110 destination = adjustDestination;
1111 panAnimationDelta = destination + currentScrollPosition;
1112 velocityOfLastPan = Math.Abs(panAnimationDelta * logValueOfDeceleration / ((float)Math.Pow(decelerationRate, panAnimationDuration) - 1));
1113 panAnimationDuration = (float)Math.Log(-DecelerationThreshold * logValueOfDeceleration / velocityOfLastPan) / logValueOfDeceleration;
1116 Debug.WriteLineIf(LayoutDebugScrollableBase, "\n" +
1117 "================================ \n" +
1118 "[decelerationRate] " + decelerationRate + "\n" +
1119 "[logValueOfDeceleration] " + logValueOfDeceleration + "\n" +
1120 "[Velocity] " + velocityOfLastPan + "\n" +
1121 "[CurrentPosition] " + currentScrollPosition + "\n" +
1122 "[CandidateDelta] " + panAnimationDelta + "\n" +
1123 "[Destination] " + destination + "\n" +
1124 "[Duration] " + panAnimationDuration + "\n" +
1125 "================================ \n"
1129 finalTargetPosition = destination;
1131 customScrollAlphaFunction = new UserAlphaFunctionDelegate(CustomScrollAlphaFunction);
1132 animation.DefaultAlphaFunction = new AlphaFunction(customScrollAlphaFunction);
1133 GC.KeepAlive(customScrollAlphaFunction);
1134 animation.Duration = (int)panAnimationDuration;
1135 animation.AnimateTo(ContentContainer, (ScrollingDirection == Direction.Horizontal) ? "PositionX" : "PositionY", destination);
1139 private void ScrollAnimationFinished(object sender, EventArgs e)
1141 OnScrollAnimationEnded();
1145 /// Adjust scrolling position by own scrolling rules.
1146 /// Override this function when developer wants to change destination of flicking.(e.g. always snap to center of item)
1148 /// This may be public opened in tizen_6.0 after ACR done. Before ACR, need to be hidden as inhouse API
1149 [EditorBrowsable(EditorBrowsableState.Never)]
1150 protected virtual float AdjustTargetPositionOfScrollAnimation(float position)
1156 /// Scroll position given to ScrollTo.
1157 /// This is the position in the opposite direction to the position of ContentContainer.
1159 /// <since_tizen> 8 </since_tizen>
1160 public Position ScrollPosition
1164 return new Position(-ContentContainer.Position);
1169 /// Current scroll position in the middle of ScrollTo animation.
1170 /// This is the position in the opposite direction to the current position of ContentContainer.
1172 /// <since_tizen> 8 </since_tizen>
1173 public Position ScrollCurrentPosition
1177 return new Position(-ContentContainer.CurrentPosition);