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.
18 using System.Collections;
19 using System.Collections.Generic;
20 using System.Collections.Specialized;
21 using System.Windows.Input;
22 using System.ComponentModel;
23 using Tizen.NUI.BaseComponents;
24 using Tizen.NUI.Binding;
26 namespace Tizen.NUI.Components
29 /// This class provides a View that can layouting items in list and grid with high performance.
31 [EditorBrowsable(EditorBrowsableState.Never)]
32 public class CollectionView : RecyclerView
35 /// Binding Property of selected item in single selection.
37 [EditorBrowsable(EditorBrowsableState.Never)]
38 public static readonly BindableProperty SelectedItemProperty =
39 BindableProperty.Create(nameof(SelectedItem), typeof(object), typeof(CollectionView), null,
40 propertyChanged: (bindable, oldValue, newValue) =>
42 var colView = (CollectionView)bindable;
43 oldValue = colView.selectedItem;
44 colView.selectedItem = newValue;
45 var args = new SelectionChangedEventArgs(oldValue, newValue);
47 foreach (RecyclerViewItem item in colView.ContentContainer.Children.Where((item) => item is RecyclerViewItem))
49 if (item.BindingContext == null) continue;
50 if (item.BindingContext == oldValue) item.IsSelected = false;
51 else if (item.BindingContext == newValue) item.IsSelected = true;
54 SelectionPropertyChanged(colView, args);
56 defaultValueCreator: (bindable) =>
58 var colView = (CollectionView)bindable;
59 return colView.selectedItem;
63 /// Binding Property of selected items list in multiple selection.
65 [EditorBrowsable(EditorBrowsableState.Never)]
66 public static readonly BindableProperty SelectedItemsProperty =
67 BindableProperty.Create(nameof(SelectedItems), typeof(IList<object>), typeof(CollectionView), null,
68 propertyChanged: (bindable, oldValue, newValue) =>
70 var colView = (CollectionView)bindable;
71 var oldSelection = colView.selectedItems ?? selectEmpty;
72 //FIXME : CoerceSelectedItems calls only isCreatedByXaml
73 var newSelection = (SelectionList)CoerceSelectedItems(colView, newValue);
74 colView.selectedItems = newSelection;
75 colView.SelectedItemsPropertyChanged(oldSelection, newSelection);
77 defaultValueCreator: (bindable) =>
79 var colView = (CollectionView)bindable;
80 colView.selectedItems = colView.selectedItems ?? new SelectionList(colView);
81 return colView.selectedItems;
85 /// Binding Property of selected items list in multiple selection.
87 [EditorBrowsable(EditorBrowsableState.Never)]
88 public static readonly BindableProperty SelectionModeProperty =
89 BindableProperty.Create(nameof(SelectionMode), typeof(ItemSelectionMode), typeof(CollectionView), ItemSelectionMode.None,
90 propertyChanged: (bindable, oldValue, newValue) =>
92 var colView = (CollectionView)bindable;
93 oldValue = colView.selectionMode;
94 colView.selectionMode = (ItemSelectionMode)newValue;
95 SelectionModePropertyChanged(colView, oldValue, newValue);
97 defaultValueCreator: (bindable) =>
99 var colView = (CollectionView)bindable;
100 return colView.selectionMode;
104 private static readonly IList<object> selectEmpty = new List<object>(0);
105 private DataTemplate itemTemplate = null;
106 private IEnumerable itemsSource = null;
107 private ItemsLayouter itemsLayouter = null;
108 private DataTemplate groupHeaderTemplate;
109 private DataTemplate groupFooterTemplate;
110 private bool isGrouped;
111 private bool wasRelayouted = false;
112 private bool needInitalizeLayouter = false;
113 private object selectedItem;
114 private SelectionList selectedItems;
115 private bool suppressSelectionChangeNotification;
116 private ItemSelectionMode selectionMode = ItemSelectionMode.None;
117 private RecyclerViewItem header;
118 private RecyclerViewItem footer;
119 private View focusedView;
120 private int prevFocusedDataIndex = 0;
121 private List<RecyclerViewItem> recycleGroupHeaderCache { get; } = new List<RecyclerViewItem>();
122 private List<RecyclerViewItem> recycleGroupFooterCache { get; } = new List<RecyclerViewItem>();
125 /// Base constructor.
127 [EditorBrowsable(EditorBrowsableState.Never)]
128 public CollectionView() : base()
131 SetKeyboardNavigationSupport(true);
135 /// Base constructor with ItemsSource
137 /// <param name="itemsSource">item's data source</param>
138 [EditorBrowsable(EditorBrowsableState.Never)]
139 public CollectionView(IEnumerable itemsSource) : this()
141 ItemsSource = itemsSource;
145 /// Base constructor with ItemsSource, ItemsLayouter and ItemTemplate
147 /// <param name="itemsSource">item's data source</param>
148 /// <param name="layouter">item's layout manager</param>
149 /// <param name="template">item's view template with data bindings</param>
150 [EditorBrowsable(EditorBrowsableState.Never)]
151 public CollectionView(IEnumerable itemsSource, ItemsLayouter layouter, DataTemplate template) : this()
153 ItemsSource = itemsSource;
154 ItemTemplate = template;
155 ItemsLayouter = layouter;
159 /// Event of Selection changed.
160 /// old selection list and new selection will be provided.
162 [EditorBrowsable(EditorBrowsableState.Never)]
163 public event EventHandler<SelectionChangedEventArgs> SelectionChanged;
166 /// Align item in the viewport when ScrollTo() calls.
168 [EditorBrowsable(EditorBrowsableState.Never)]
169 public enum ItemScrollTo
172 /// Scroll to show item in nearest viewport on scroll direction.
173 /// item is above the scroll viewport, item will be came into front,
174 /// item is under the scroll viewport, item will be came into end,
175 /// item is in the scroll viewport, no scroll.
179 /// Scroll to show item in start of the viewport.
183 /// Scroll to show item in center of the viewport.
187 /// Scroll to show item in end of the viewport.
193 /// Item's source data.
195 [EditorBrowsable(EditorBrowsableState.Never)]
196 public override IEnumerable ItemsSource
204 if (itemsSource != null)
206 // Clearing old data!
207 if (itemsSource is INotifyCollectionChanged prevNotifyCollectionChanged)
209 prevNotifyCollectionChanged.CollectionChanged -= CollectionChanged;
211 itemsLayouter.Clear();
212 if (selectedItem != null) selectedItem = null;
213 if (selectedItems != null)
215 selectedItems.Clear();
222 if (InternalItemSource != null) InternalItemSource.Dispose();
226 if (itemsSource is INotifyCollectionChanged newNotifyCollectionChanged)
228 newNotifyCollectionChanged.CollectionChanged += CollectionChanged;
231 if (InternalItemSource != null) InternalItemSource.Dispose();
232 InternalItemSource = ItemsSourceFactory.Create(this);
234 if (itemsLayouter == null) return;
236 needInitalizeLayouter = true;
242 /// DataTemplate for items.
244 [EditorBrowsable(EditorBrowsableState.Never)]
245 public override DataTemplate ItemTemplate
253 itemTemplate = value;
260 needInitalizeLayouter = true;
268 [EditorBrowsable(EditorBrowsableState.Never)]
269 public virtual ItemsLayouter ItemsLayouter
273 return itemsLayouter;
277 itemsLayouter = value;
278 base.InternalItemsLayouter = ItemsLayouter;
281 needInitalizeLayouter = false;
285 needInitalizeLayouter = true;
287 var styleName = "Tizen.NUI.Components." + (itemsLayouter is LinearLayouter? "LinearLayouter" : (itemsLayouter is GridLayouter ? "GridLayouter" : "ItemsLayouter"));
288 ViewStyle layouterStyle = ThemeManager.GetStyle(styleName);
289 if (layouterStyle != null)
291 itemsLayouter.Padding = new Extents(layouterStyle.Padding);
298 /// Scrolling direction to display items layout.
300 [EditorBrowsable(EditorBrowsableState.Never)]
301 public new Direction ScrollingDirection
305 return base.ScrollingDirection;
309 if (base.ScrollingDirection != value)
311 base.ScrollingDirection = value;
312 needInitalizeLayouter = true;
319 /// Selected item in single selection.
321 [EditorBrowsable(EditorBrowsableState.Never)]
322 public object SelectedItem
324 get => GetValue(SelectedItemProperty);
325 set => SetValue(SelectedItemProperty, value);
329 /// Selected items list in multiple selection.
331 [EditorBrowsable(EditorBrowsableState.Never)]
332 public IList<object> SelectedItems
334 get => (IList<object>)GetValue(SelectedItemsProperty);
335 // set => SetValue(SelectedItemsProperty, new SelectionList(this, value));
339 /// Selection mode to handle items selection. See ItemSelectionMode for details.
341 [EditorBrowsable(EditorBrowsableState.Never)]
342 public ItemSelectionMode SelectionMode
344 get => (ItemSelectionMode)GetValue(SelectionModeProperty);
345 set => SetValue(SelectionModeProperty, value);
349 /// Command of selection changed.
351 [EditorBrowsable(EditorBrowsableState.Never)]
352 public ICommand SelectionChangedCommand { set; get; }
355 /// Command parameter of selection changed.
357 [EditorBrowsable(EditorBrowsableState.Never)]
358 public object SelectionChangedCommandParameter { set; get; }
361 /// Header item which placed in top-most position.
362 /// note : internal index and count will be increased.
364 [EditorBrowsable(EditorBrowsableState.Never)]
365 public RecyclerViewItem Header
372 //ContentContainer.Remove(header);
373 Utility.Dispose(header);
378 value.ParentItemsView = this;
379 value.IsHeader = true;
380 ContentContainer.Add(value);
383 needInitalizeLayouter = true;
389 /// Footer item which placed in bottom-most position.
390 /// note : internal count will be increased.
392 [EditorBrowsable(EditorBrowsableState.Never)]
393 public RecyclerViewItem Footer
400 //ContentContainer.Remove(footer);
401 Utility.Dispose(footer);
405 value.Index = InternalItemSource?.Count ?? 0;
406 value.ParentItemsView = this;
407 value.IsFooter = true;
408 ContentContainer.Add(value);
411 needInitalizeLayouter = true;
417 /// Boolean flag of group feature existence.
419 [EditorBrowsable(EditorBrowsableState.Never)]
420 public bool IsGrouped
426 needInitalizeLayouter = true;
427 //Need to re-intialize Internal Item Source.
428 if (InternalItemSource != null)
430 InternalItemSource.Dispose();
431 InternalItemSource = null;
433 if (ItemsSource != null)
434 InternalItemSource = ItemsSourceFactory.Create(this);
440 /// DataTemplate of group header. Group feature is not supported yet.
442 [EditorBrowsable(EditorBrowsableState.Never)]
443 public DataTemplate GroupHeaderTemplate
447 return groupHeaderTemplate;
451 groupHeaderTemplate = value;
452 needInitalizeLayouter = true;
458 /// DataTemplate of group footer. Group feature is not supported yet.
460 [EditorBrowsable(EditorBrowsableState.Never)]
461 public DataTemplate GroupFooterTemplate
465 return groupFooterTemplate;
469 groupFooterTemplate = value;
470 needInitalizeLayouter = true;
476 /// Internal encapsulated items data source.
478 internal new IGroupableItemSource InternalItemSource
482 return (base.InternalItemSource as IGroupableItemSource);
486 base.InternalItemSource = value;
491 /// Size strategy of measuring scroll content. see details in ItemSizingStrategy.
493 [EditorBrowsable(EditorBrowsableState.Never)]
494 internal ItemSizingStrategy SizingStrategy { get; set; }
497 [EditorBrowsable(EditorBrowsableState.Never)]
498 public override void OnRelayout(Vector2 size, RelayoutContainer container)
500 base.OnRelayout(size, container);
502 wasRelayouted = true;
503 if (needInitalizeLayouter) Init();
507 [EditorBrowsable(EditorBrowsableState.Never)]
508 public override void NotifyDataSetChanged()
510 if (selectedItem != null)
514 if (selectedItems != null)
516 selectedItems.Clear();
519 base.NotifyDataSetChanged();
523 [EditorBrowsable(EditorBrowsableState.Never)]
524 public override View GetNextFocusableView(View currentFocusedView, View.FocusDirection direction, bool loopEnabled)
526 View nextFocusedView = null;
528 if (focusedView == null)
530 // If focusedView is null, find child which has previous data index
531 if (ContentContainer.Children.Count > 0 && InternalItemSource.Count > 0)
533 for (int i = 0; i < ContentContainer.Children.Count; i++)
535 RecyclerViewItem item = Children[i] as RecyclerViewItem;
536 if (item?.Index == prevFocusedDataIndex)
538 nextFocusedView = item;
546 // If this is not first focus, request next focus to Layouter
547 nextFocusedView = ItemsLayouter.RequestNextFocusableView(currentFocusedView, direction, loopEnabled);
550 if (nextFocusedView != null)
552 // Check next focused view is inside of visible area.
553 // If it is not, move scroll position to make it visible.
554 Position scrollPosition = ContentContainer.CurrentPosition;
555 float targetPosition = -(ScrollingDirection == Direction.Horizontal ? scrollPosition.X : scrollPosition.Y);
557 float left = nextFocusedView.Position.X;
558 float right = nextFocusedView.Position.X + nextFocusedView.Size.Width;
559 float top = nextFocusedView.Position.Y;
560 float bottom = nextFocusedView.Position.Y + nextFocusedView.Size.Height;
562 float visibleRectangleLeft = -scrollPosition.X;
563 float visibleRectangleRight = -scrollPosition.X + Size.Width;
564 float visibleRectangleTop = -scrollPosition.Y;
565 float visibleRectangleBottom = -scrollPosition.Y + Size.Height;
567 if (ScrollingDirection == Direction.Horizontal)
569 if ((direction == View.FocusDirection.Left || direction == View.FocusDirection.Up) && left < visibleRectangleLeft)
571 targetPosition = left;
573 else if ((direction == View.FocusDirection.Right || direction == View.FocusDirection.Down) && right > visibleRectangleRight)
575 targetPosition = right - Size.Width;
580 if ((direction == View.FocusDirection.Up || direction == View.FocusDirection.Left) && top < visibleRectangleTop)
582 targetPosition = top;
584 else if ((direction == View.FocusDirection.Down || direction == View.FocusDirection.Right) && bottom > visibleRectangleBottom)
586 targetPosition = bottom - Size.Height;
590 focusedView = nextFocusedView;
591 prevFocusedDataIndex = (nextFocusedView as RecyclerViewItem)?.Index ?? -1;
593 ScrollTo(targetPosition, true);
597 // If nextView is null, it means that we should move focus to outside of Control.
598 // Return FocusableView depending on direction.
601 case View.FocusDirection.Left:
603 nextFocusedView = LeftFocusableView;
606 case View.FocusDirection.Right:
608 nextFocusedView = RightFocusableView;
611 case View.FocusDirection.Up:
613 nextFocusedView = UpFocusableView;
616 case View.FocusDirection.Down:
618 nextFocusedView = DownFocusableView;
623 if (nextFocusedView != null)
629 //If FocusableView doesn't exist, not move focus.
630 nextFocusedView = focusedView;
634 return nextFocusedView;
638 /// Update selected items list in multiple selection.
640 /// <param name="newSelection">updated selection list by user</param>
641 [EditorBrowsable(EditorBrowsableState.Never)]
642 public void UpdateSelectedItems(IList<object> newSelection)
644 var oldSelection = new List<object>(SelectedItems);
646 suppressSelectionChangeNotification = true;
648 SelectedItems.Clear();
650 if (newSelection?.Count > 0)
652 for (int n = 0; n < newSelection.Count; n++)
654 SelectedItems.Add(newSelection[n]);
658 suppressSelectionChangeNotification = false;
660 SelectedItemsPropertyChanged(oldSelection, newSelection);
664 /// Scroll to specific position with or without animation.
666 /// <param name="position">Destination.</param>
667 /// <param name="animate">Scroll with or without animation</param>
668 [EditorBrowsable(EditorBrowsableState.Never)]
669 public new void ScrollTo(float position, bool animate) => base.ScrollTo(position, animate);
672 /// Scroll to specific item's aligned position with or without animation.
674 /// <param name="index">Target item index of dataset.</param>
675 /// <param name="animate">Boolean flag of animation.</param>
676 /// <param name="align">Align state of item. see details in ItemScrollTo.</param>
677 [EditorBrowsable(EditorBrowsableState.Never)]
678 public virtual void ScrollTo(int index, bool animate = false, ItemScrollTo align = ItemScrollTo.Nearest)
680 if (ItemsLayouter == null) throw new Exception("Item Layouter must exist.");
682 float scrollPos, curPos, curSize, curItemSize;
683 (float x, float y) = ItemsLayouter.GetItemPosition(index);
684 (float width, float height) = ItemsLayouter.GetItemSize(index);
685 if (ScrollingDirection == Direction.Horizontal)
688 curPos = ScrollPosition.X;
689 curSize = Size.Width;
695 curPos = ScrollPosition.Y;
696 curSize = Size.Height;
697 curItemSize = height;
700 //Console.WriteLine("[NUI] ScrollTo [{0}:{1}], curPos{2}, itemPos{3}, curSize{4}, itemSize{5}", InternalItemSource.GetPosition(item), align, curPos, scrollPos, curSize, curItemSize);
703 case ItemScrollTo.Start:
706 case ItemScrollTo.Center:
707 scrollPos = scrollPos - (curSize / 2) + (curItemSize / 2);
709 case ItemScrollTo.End:
710 scrollPos = scrollPos - curSize + curItemSize;
712 case ItemScrollTo.Nearest:
713 if (scrollPos < curPos - curItemSize)
715 // item is placed before the current screen. scrollTo.Top
717 else if (scrollPos >= curPos + curSize + curItemSize)
719 // item is placed after the current screen. scrollTo.End
720 scrollPos = scrollPos - curSize + curItemSize;
724 // item is in the scroller. ScrollTo() is ignored.
730 //Console.WriteLine("[NUI] ScrollTo [{0}]-------------------", scrollPos);
731 base.ScrollTo(scrollPos, animate);
735 /// Apply style to CollectionView
737 /// <param name="viewStyle">The style to apply.</param>
738 [EditorBrowsable(EditorBrowsableState.Never)]
739 public override void ApplyStyle(ViewStyle viewStyle)
741 base.ApplyStyle(viewStyle);
742 if (viewStyle != null)
744 //Extension = RecyclerViewItemStyle.CreateExtension();
746 if (itemsLayouter != null)
748 string styleName = "Tizen.NUI.Compoenents." + (itemsLayouter is LinearLayouter? "LinearLayouter" : (itemsLayouter is GridLayouter ? "GridLayouter" : "ItemsLayouter"));
749 ViewStyle layouterStyle = ThemeManager.GetStyle(styleName);
750 if (layouterStyle != null)
751 itemsLayouter.Padding = new Extents(layouterStyle.Padding);
755 // Realize and Decorate the item.
756 internal override RecyclerViewItem RealizeItem(int index)
758 RecyclerViewItem item;
759 if (index == 0 && Header != null)
765 if (index == InternalItemSource.Count - 1 && Footer != null)
773 var context = InternalItemSource.GetItem(index);
774 if (InternalItemSource.IsGroupHeader(index))
776 DataTemplate templ = (groupHeaderTemplate as DataTemplateSelector)?.SelectDataTemplate(context, this) ?? groupHeaderTemplate;
778 RecyclerViewItem groupHeader = PopRecycleGroupCache(templ, true);
779 if (groupHeader == null)
781 groupHeader = (RecyclerViewItem)DataTemplateExtensions.CreateContent(groupHeaderTemplate, context, this);
783 groupHeader.Template = templ;
784 groupHeader.isGroupHeader = true;
785 groupHeader.isGroupFooter = false;
786 ContentContainer.Add(groupHeader);
788 groupHeader.ParentItemsView = this;
789 groupHeader.Index = index;
790 groupHeader.ParentGroup = context;
791 groupHeader.BindingContext = context;
795 else if (InternalItemSource.IsGroupFooter(index))
797 DataTemplate templ = (groupFooterTemplate as DataTemplateSelector)?.SelectDataTemplate(context, this) ?? groupFooterTemplate;
799 RecyclerViewItem groupFooter = PopRecycleGroupCache(templ, false);
800 if (groupFooter == null)
802 groupFooter = (RecyclerViewItem)DataTemplateExtensions.CreateContent(groupFooterTemplate, context, this);
804 groupFooter.Template = templ;
805 groupFooter.isGroupHeader = false;
806 groupFooter.isGroupFooter = true;
807 ContentContainer.Add(groupFooter);
809 groupFooter.ParentItemsView = this;
810 groupFooter.Index = index;
811 groupFooter.ParentGroup = context;
812 groupFooter.BindingContext = context;
819 item = base.RealizeItem(index);
820 item.ParentGroup = InternalItemSource.GetGroupParent(index);
825 item = base.RealizeItem(index);
828 switch (SelectionMode)
830 case ItemSelectionMode.Single:
831 case ItemSelectionMode.SingleAlways:
832 if (item.BindingContext != null && item.BindingContext == SelectedItem)
834 item.IsSelected = true;
838 case ItemSelectionMode.Multiple:
839 if ((item.BindingContext != null) && (SelectedItems?.Contains(item.BindingContext) ?? false))
841 item.IsSelected = true;
844 case ItemSelectionMode.None:
845 item.IsSelectable = false;
851 // Unrealize and caching the item.
852 internal override void UnrealizeItem(RecyclerViewItem item, bool recycle = true)
854 if (item == null) return;
865 if (item.isGroupHeader || item.isGroupFooter)
868 item.ParentItemsView = null;
869 item.BindingContext = null;
870 item.IsPressed = false;
871 item.IsSelected = false;
872 item.IsEnabled = true;
874 //item.Relayout -= OnItemRelayout;
875 if (!recycle || !PushRecycleGroupCache(item))
876 Utility.Dispose(item);
880 base.UnrealizeItem(item, recycle);
883 internal void SelectedItemsPropertyChanged(IList<object> oldSelection, IList<object> newSelection)
885 if (suppressSelectionChangeNotification)
890 foreach (RecyclerViewItem item in ContentContainer.Children.Where((item) => item is RecyclerViewItem))
892 if (item.BindingContext == null) continue;
893 if (newSelection.Contains(item.BindingContext))
895 if (!item.IsSelected) item.IsSelected = true;
899 if (item.IsSelected) item.IsSelected = false;
902 SelectionPropertyChanged(this, new SelectionChangedEventArgs(oldSelection, newSelection));
904 OnPropertyChanged(SelectedItemsProperty.PropertyName);
908 /// Internal selection callback.
910 [EditorBrowsable(EditorBrowsableState.Never)]
911 protected virtual void OnSelectionChanged(SelectionChangedEventArgs args)
917 /// Adjust scrolling position by own scrolling rules.
918 /// Override this function when developer wants to change destination of flicking.(e.g. always snap to center of item)
920 /// <param name="position">Scroll position which is calculated by ScrollableBase</param>
921 /// <returns>Adjusted scroll destination</returns>
922 [EditorBrowsable(EditorBrowsableState.Never)]
923 protected override float AdjustTargetPositionOfScrollAnimation(float position)
925 // Destination is depending on implementation of layout manager.
926 // Get destination from layout manager.
927 return ItemsLayouter.CalculateCandidateScrollPosition(position);
931 /// OnScroll event callback.
933 /// <param name="source">Scroll source object</param>
934 /// <param name="args">Scroll event argument</param>
935 [EditorBrowsable(EditorBrowsableState.Never)]
936 protected override void OnScrolling(object source, ScrollEventArgs args)
938 if (disposed) return;
940 if (needInitalizeLayouter)
942 ItemsLayouter.Initialize(this);
943 needInitalizeLayouter = false;
946 base.OnScrolling(source, args);
950 /// Dispose ItemsView and all children on it.
952 /// <param name="type">Dispose type.</param>
953 protected override void Dispose(DisposeTypes type)
960 if (type == DisposeTypes.Explicit)
962 // From now on, no need to use this properties,
963 // so remove reference, to push it into garbage collector.
965 // Arugable to disposing user-created members.
969 Utility.Dispose(Header);
974 Utility.Dispose(Footer);
979 groupHeaderTemplate = null;
980 groupFooterTemplate = null;
982 if (selectedItem != null)
986 if (selectedItems != null)
988 selectedItems.Clear();
989 selectedItems = null;
991 if (InternalItemSource != null)
993 InternalItemSource.Dispose();
994 InternalItemSource = null;
996 if (recycleGroupHeaderCache != null)
998 foreach(RecyclerViewItem item in recycleGroupHeaderCache)
1000 UnrealizeItem(item, false);
1002 recycleGroupHeaderCache.Clear();
1004 if (recycleGroupFooterCache != null)
1006 foreach(RecyclerViewItem item in recycleGroupFooterCache)
1008 UnrealizeItem(item, false);
1010 recycleGroupFooterCache.Clear();
1017 private static void SelectionPropertyChanged(CollectionView colView, SelectionChangedEventArgs args)
1019 var command = colView.SelectionChangedCommand;
1021 if (command != null)
1023 var commandParameter = colView.SelectionChangedCommandParameter;
1025 if (command.CanExecute(commandParameter))
1027 command.Execute(commandParameter);
1030 colView.SelectionChanged?.Invoke(colView, args);
1031 colView.OnSelectionChanged(args);
1034 private static object CoerceSelectedItems(BindableObject bindable, object value)
1038 return new SelectionList((CollectionView)bindable);
1041 if (value is SelectionList)
1046 return new SelectionList((CollectionView)bindable, value as IList<object>);
1049 private static void SelectionModePropertyChanged(BindableObject bindable, object oldValue, object newValue)
1051 var colView = (CollectionView)bindable;
1053 var oldMode = (ItemSelectionMode)oldValue;
1054 var newMode = (ItemSelectionMode)newValue;
1056 IList<object> previousSelection = new List<object>();
1057 IList<object> newSelection = new List<object>();
1061 case ItemSelectionMode.None:
1063 case ItemSelectionMode.Single:
1064 if (colView.SelectedItem != null)
1066 previousSelection.Add(colView.SelectedItem);
1069 case ItemSelectionMode.Multiple:
1070 previousSelection = colView.SelectedItems;
1076 case ItemSelectionMode.None:
1078 case ItemSelectionMode.Single:
1079 if (colView.SelectedItem != null)
1081 newSelection.Add(colView.SelectedItem);
1084 case ItemSelectionMode.Multiple:
1085 newSelection = colView.SelectedItems;
1089 if (previousSelection.Count == newSelection.Count)
1091 if (previousSelection.Count == 0 || (previousSelection[0] == newSelection[0]))
1093 // Both selections are empty or have the same single item; no reason to signal a change
1098 var args = new SelectionChangedEventArgs(previousSelection, newSelection);
1099 SelectionPropertyChanged(colView, args);
1104 if (ItemsSource == null) return;
1105 if (ItemsLayouter == null) return;
1106 if (ItemTemplate == null) return;
1108 if (disposed) return;
1109 if (needInitalizeLayouter)
1111 if (InternalItemSource == null) return;
1113 InternalItemSource.HasHeader = (header != null);
1114 InternalItemSource.HasFooter = (footer != null);
1117 if (!wasRelayouted) return;
1119 if (needInitalizeLayouter)
1121 ItemsLayouter.Initialize(this);
1122 needInitalizeLayouter = false;
1124 ItemsLayouter.RequestLayout(0.0f, true);
1126 if (ScrollingDirection == Direction.Horizontal)
1128 ContentContainer.SizeWidth = ItemsLayouter.CalculateLayoutOrientationSize();
1132 ContentContainer.SizeHeight = ItemsLayouter.CalculateLayoutOrientationSize();
1136 private bool PushRecycleGroupCache(RecyclerViewItem item)
1138 if (item == null) throw new ArgumentNullException(nameof(item));
1139 if (RecycleCache.Count >= 20) return false;
1140 if (item.Template == null) return false;
1141 if (item.isGroupHeader)
1143 recycleGroupHeaderCache.Add(item);
1145 else if (item.isGroupFooter)
1147 recycleGroupFooterCache.Add(item);
1155 private RecyclerViewItem PopRecycleGroupCache(DataTemplate Template, bool isHeader)
1157 RecyclerViewItem viewItem = null;
1159 var Cache = (isHeader ? recycleGroupHeaderCache : recycleGroupFooterCache);
1160 for (int i = 0; i < Cache.Count; i++)
1162 viewItem = Cache[i];
1163 if (Template == viewItem.Template) break;
1166 if (viewItem != null)
1168 Cache.Remove(viewItem);
1173 private void CollectionChanged(object sender, NotifyCollectionChangedEventArgs args)
1175 switch (args.Action)
1177 case NotifyCollectionChangedAction.Add:
1179 case NotifyCollectionChangedAction.Remove:
1180 // Clear removed items.
1181 if (args.OldItems != null)
1183 if (args.OldItems.Contains(selectedItem))
1185 selectedItem = null;
1188 if (selectedItems != null)
1190 foreach (object removed in args.OldItems)
1192 if (selectedItems.Contains(removed))
1194 selectedItems.Remove(removed);
1200 case NotifyCollectionChangedAction.Replace:
1202 case NotifyCollectionChangedAction.Move:
1204 case NotifyCollectionChangedAction.Reset:
1207 throw new ArgumentOutOfRangeException(nameof(args));