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authorJason Smith <jason.smith@xamarin.com>2016-04-26 15:35:52 -0400
committerJason Smith <jason.smith@xamarin.com>2016-04-26 15:35:52 -0400
commit409e10528495238a680c1bf3867a71f758b0d452 (patch)
tree0cb19f682b0b192ebad3dc0c77cfe32974abe09c /Xamarin.Forms.Platform.Android
parent9ae4ea3c82444561353eb77bf746f96cdbfb4583 (diff)
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Carousel clean (#135)
CarouselView moving to preview repo
Diffstat (limited to 'Xamarin.Forms.Platform.Android')
-rw-r--r--Xamarin.Forms.Platform.Android/Renderers/CarouselViewRenderer.cs1246
-rw-r--r--Xamarin.Forms.Platform.Android/Xamarin.Forms.Platform.Android.csproj1
2 files changed, 0 insertions, 1247 deletions
diff --git a/Xamarin.Forms.Platform.Android/Renderers/CarouselViewRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/CarouselViewRenderer.cs
deleted file mode 100644
index 7b0da7aa..00000000
--- a/Xamarin.Forms.Platform.Android/Renderers/CarouselViewRenderer.cs
+++ /dev/null
@@ -1,1246 +0,0 @@
-using System;
-using System.Collections.Specialized;
-using System.ComponentModel;
-using System.Collections.Generic;
-using System.Linq;
-using Android.Content;
-using Android.Graphics;
-using Android.Views;
-using Android.Support.V7.Widget;
-using static System.Diagnostics.Debug;
-using IntRectangle = System.Drawing.Rectangle;
-using IntSize = System.Drawing.Size;
-using IntPoint = System.Drawing.Point;
-using AndroidView = Android.Views.View;
-using Adapter = Android.Support.V7.Widget.RecyclerView.Adapter;
-using Recycler = Android.Support.V7.Widget.RecyclerView.Recycler;
-using State = Android.Support.V7.Widget.RecyclerView.State;
-using ViewHolder = Android.Support.V7.Widget.RecyclerView.ViewHolder;
-using Observer = Android.Support.V7.Widget.RecyclerView.AdapterDataObserver;
-using LayoutManager = Android.Support.V7.Widget.RecyclerView.LayoutManager;
-using LayoutParams = Android.Support.V7.Widget.RecyclerView.LayoutParams;
-
-namespace Xamarin.Forms.Platform.Android
-{
- internal static class CarouselViewExtensions
- {
- internal static IntVector BoundTranslation(this IntRectangle viewport, IntVector delta, IntRectangle bound)
- {
- // TODO: generalize the math
- Assert(delta.X == 0 || delta.Y == 0);
-
- IntVector start = viewport.LeadingCorner(delta);
- IntVector end = start + delta;
- IntVector clampedEnd = end.Clamp(bound);
- IntVector clampedDelta = clampedEnd - start;
- return clampedDelta;
- }
- internal static IntVector Clamp(this IntVector position, IntRectangle bound)
- {
- return new IntVector(
- x: position.X.Clamp(bound.Left, bound.Right),
- y: position.Y.Clamp(bound.Top, bound.Bottom)
- );
- }
- internal static IntVector LeadingCorner(this IntRectangle rectangle, IntVector delta)
- {
- return new IntVector(
- x: delta.X < 0 ? rectangle.Left : rectangle.Right,
- y: delta.Y < 0 ? rectangle.Top : rectangle.Bottom
- );
- }
- internal static IntVector Center(this IntRectangle rectangle)
- {
- return (IntVector)rectangle.Location + (IntVector)rectangle.Size / 2;
- }
- internal static int Area(this IntRectangle rectangle)
- {
- return rectangle.Width * rectangle.Height;
- }
-
- internal static Rectangle ToFormsRectangle(this IntRectangle rectangle, Context context)
- {
- return new Rectangle(
- x: context.FromPixels(rectangle.Left),
- y: context.FromPixels(rectangle.Top),
- width: context.FromPixels(rectangle.Width),
- height: context.FromPixels(rectangle.Height)
- );
- }
- internal static Rect ToAndroidRectangle(this IntRectangle rectangle)
- {
- return new Rect(
- left: rectangle.Left,
- right: rectangle.Right,
- top: rectangle.Top,
- bottom: rectangle.Bottom
- );
- }
-
- internal static bool LexicographicallyLess(this IntPoint source, IntPoint target)
- {
- if (source.X < target.X)
- return true;
-
- if (source.X > target.X)
- return false;
-
- return source.Y < target.Y;
- }
- internal static int[] ToRange(this Tuple<int, int> startAndCount)
- {
- return Enumerable.Range(startAndCount.Item1, startAndCount.Item2).ToArray();
- }
- }
-
- internal struct IntVector
- {
- public static explicit operator IntVector(IntSize size)
- {
- return new IntVector(size.Width, size.Height);
- }
- public static explicit operator IntVector(IntPoint point)
- {
- return new IntVector(point.X, point.Y);
- }
- public static implicit operator IntPoint(IntVector vector)
- {
- return new IntPoint(vector.X, vector.Y);
- }
- public static implicit operator IntSize(IntVector vector)
- {
- return new IntSize(vector.X, vector.Y);
- }
-
- public static bool operator ==(IntVector lhs, IntVector rhs)
- {
- return lhs.X == rhs.X && lhs.Y == rhs.Y;
- }
- public static bool operator !=(IntVector lhs, IntVector rhs)
- {
- return !(lhs == rhs);
- }
- public static IntRectangle operator -(IntRectangle source, IntVector vector) => source + -vector;
- public static IntRectangle operator +(IntRectangle source, IntVector vector) =>
- new IntRectangle(source.Location + vector, source.Size);
-
- public static IntVector operator -(IntVector vector, IntVector other) => vector + -other;
- public static IntVector operator +(IntVector vector, IntVector other) =>
- new IntVector(
- x: vector.X + other.X,
- y: vector.Y + other.Y
- );
-
- public static IntPoint operator -(IntPoint point, IntVector delta) => point + -delta;
- public static IntPoint operator +(IntPoint point, IntVector delta) =>
- new IntPoint(
- x: point.X + delta.X,
- y: point.Y + delta.Y
- );
-
- public static IntVector operator -(IntVector vector) => vector * -1;
- public static IntVector operator *(IntVector vector, int scaler) =>
- new IntVector(
- x: vector.X * scaler,
- y: vector.Y * scaler
- );
- public static IntVector operator /(IntVector vector, int scaler) =>
- new IntVector(
- x: vector.X / scaler,
- y: vector.Y / scaler
- );
-
- public static IntVector operator *(IntVector vector, double scaler) =>
- new IntVector(
- x: (int)(vector.X * scaler),
- y: (int)(vector.Y * scaler)
- );
- public static IntVector operator /(IntVector vector, double scaler) => vector * (1 / scaler);
-
- internal static IntVector Origin = new IntVector(0, 0);
- internal static IntVector XUnit = new IntVector(1, 0);
- internal static IntVector YUnit = new IntVector(0, 1);
-
- #region Fields
- readonly int _x;
- readonly int _y;
- #endregion
-
- internal IntVector(int x, int y)
- {
- _x = x;
- _y = y;
- }
-
- internal int X => _x;
- internal int Y => _y;
-
- public override bool Equals(object obj)
- {
- return base.Equals(obj);
- }
- public override int GetHashCode()
- {
- return base.GetHashCode();
- }
- public override string ToString()
- {
- return $"{X},{Y}";
- }
- }
-
- [Flags]
- internal enum MeasureSpecificationType
- {
- Unspecified = 0,
- Exactly = 0x1 << 31,
- AtMost = 0x1 << 32,
- Mask = Exactly | AtMost
- }
- internal struct MeasureSpecification
- {
- public static explicit operator MeasureSpecification(int measureSpecification)
- {
- return new MeasureSpecification(measureSpecification);
- }
- public static implicit operator int(MeasureSpecification measureSpecification)
- {
- return measureSpecification.Encode();
- }
-
- #region Fields
- readonly int _value;
- readonly MeasureSpecificationType _type;
- #endregion
-
- internal MeasureSpecification(int measureSpecification)
- {
- _value = measureSpecification & (int)~MeasureSpecificationType.Mask;
- _type = (MeasureSpecificationType)(measureSpecification & (int)MeasureSpecificationType.Mask);
- }
- internal MeasureSpecification(int value, MeasureSpecificationType measureSpecification)
- {
- _value = value;
- _type = measureSpecification;
- }
-
- internal int Value => _value;
- internal MeasureSpecificationType Type => _type;
- internal int Encode() => Value | (int)Type;
-
- public override string ToString()
- {
- return string.Format("{0} {1}", Value, Type);
- }
- }
-
- public class CarouselViewRenderer : ViewRenderer<CarouselView, RecyclerView>
- {
- // http://developer.android.com/reference/android/support/v7/widget/RecyclerView.html
- // http://developer.android.com/training/material/lists-cards.html
- // http://wiresareobsolete.com/2014/09/building-a-recyclerview-layoutmanager-part-1/
-
- internal class VirtualLayoutManager : PhysicalLayoutManager.VirtualLayoutManager
- {
- #region Fields
- const int Columns = 1;
- IntSize _itemSize;
- #endregion
-
- #region Private Members
- int GetPosition(int itemCount, int positionOrigin, int x, bool exclusive = false)
- {
- int position = x / _itemSize.Width + positionOrigin;
- bool hasRemainder = x % _itemSize.Width != 0;
-
- if (hasRemainder && x < 0)
- position--;
-
- if (!hasRemainder && exclusive)
- position--;
-
- position = position.Clamp(0, itemCount - 1);
- return position;
- }
- #endregion
-
- internal override bool CanScrollHorizontally => true;
- internal override bool CanScrollVertically => false;
-
- internal override IntRectangle GetBounds(int originPosition, State state) =>
- new IntRectangle(
- LayoutItem(originPosition, 0).Location,
- new IntSize(_itemSize.Width * state.ItemCount, _itemSize.Height)
- );
-
- internal override Tuple<int, int> GetPositions(
- int positionOrigin,
- int itemCount,
- IntRectangle viewport,
- bool includeBuffer)
- {
- // returns one item off-screen in either direction.
- int buffer = includeBuffer ? 1 : 0;
- int left = GetPosition(itemCount, positionOrigin - buffer, viewport.Left);
- int right = GetPosition(itemCount, positionOrigin + buffer, viewport.Right, exclusive: true);
-
- int start = left;
- int count = right - left + 1;
- return new Tuple<int, int>(start, count);
- }
- internal override void Layout(int positionOffset, IntSize viewportSize, ref IntVector offset)
- {
- int width = viewportSize.Width / Columns;
- int height = viewportSize.Height;
-
- if (_itemSize.Width != 0)
- offset *= (double)width / _itemSize.Width;
-
- _itemSize = new IntSize(width, height);
- }
- internal override IntRectangle LayoutItem(int positionOffset, int position)
- {
- // measure
- IntSize size = _itemSize;
-
- // layout
- var location = new IntVector((position - positionOffset) * size.Width, 0);
-
- // allocate
- return new IntRectangle(location, size);
- }
-
- public override string ToString()
- {
- return $"itemSize={_itemSize}";
- }
- }
-
- #region Private Definitions
- class OnScrollListener : RecyclerView.OnScrollListener
- {
- enum ScrollState
- {
- Idle,
- Dragging,
- Settling
- }
-
- readonly Action _onDragEnd;
- readonly Action _onDragStart;
- ScrollState _lastScrollState;
-
- internal OnScrollListener(
- Action onDragEnd,
- Action onDragStart)
- {
- _onDragEnd = onDragEnd;
- _onDragStart = onDragStart;
- }
-
- public override void OnScrollStateChanged(RecyclerView recyclerView, int newState)
- {
- var state = (ScrollState)newState;
- if (_lastScrollState != ScrollState.Dragging && state == ScrollState.Dragging)
- _onDragStart();
-
- if (_lastScrollState == ScrollState.Dragging && state != ScrollState.Dragging)
- _onDragEnd();
-
- _lastScrollState = state;
- base.OnScrollStateChanged(recyclerView, newState);
- }
- }
- class PositionUpdater : Observer
- {
- #region Fields
- readonly CarouselViewRenderer _carouselView;
- #endregion
-
- internal PositionUpdater(CarouselViewRenderer carouselView)
- {
- _carouselView = carouselView;
- }
-
- public override void OnItemRangeInserted(int positionStart, int itemCount)
- {
- if (positionStart > _carouselView._position)
- {
- // removal after the current position won't change current position
- }
- else
- {
- // raise position changed
- _carouselView._position += itemCount;
- _carouselView.OnPositionChanged();
- }
-
- base.OnItemRangeInserted(positionStart, itemCount);
- }
- public override void OnItemRangeRemoved(int positionStart, int itemCount)
- {
- Assert(itemCount == 1);
-
- if (positionStart > _carouselView._position)
- {
- // removal after the current position won't change current position
- }
- else if (positionStart == _carouselView._position &&
- positionStart != _carouselView.Adapter.ItemCount)
- {
- // raise item changed
- _carouselView.OnItemChanged();
- return;
- }
- else
- {
- // raise position changed
- _carouselView._position -= itemCount;
- _carouselView.OnPositionChanged();
- }
-
- base.OnItemRangeRemoved(positionStart, itemCount);
- }
- }
- #endregion
-
- #region Fields
- PhysicalLayoutManager _physicalLayout;
- int _position;
- bool _disposed;
- #endregion
-
- public CarouselViewRenderer()
- {
- AutoPackage = false;
- }
-
- protected override void Dispose(bool disposing)
- {
- if (disposing && !_disposed)
- {
- _disposed = true;
- if (Element != null)
- Element.CollectionChanged -= OnCollectionChanged;
- }
-
- base.Dispose(disposing);
- }
-
- #region Private Members
- void Initialize()
- {
- // cache hit? Check if the view page is already created
- RecyclerView recyclerView = Control;
- if (recyclerView != null)
- return;
-
- // cache miss
- recyclerView = new RecyclerView(Context);
- SetNativeControl(recyclerView);
-
- // layoutManager
- recyclerView.SetLayoutManager(
- layout: _physicalLayout = new PhysicalLayoutManager(
- context: Context,
- virtualLayout: new VirtualLayoutManager(),
- positionOrigin: Element.Position
- )
- );
-
- // swiping
- var dragging = false;
- recyclerView.AddOnScrollListener(
- new OnScrollListener(
- onDragStart: () => dragging = true,
- onDragEnd: () =>
- {
- dragging = false;
- var velocity = _physicalLayout.Velocity;
-
- var target = velocity.X > 0 ?
- _physicalLayout.VisiblePositions().Max() :
- _physicalLayout.VisiblePositions().Min();
- _physicalLayout.ScrollToPosition(target);
- }
- )
- );
-
- // scrolling
- var scrolling = false;
- _physicalLayout.OnBeginScroll += position => scrolling = true;
- _physicalLayout.OnEndScroll += position => scrolling = false;
-
- // appearing
- _physicalLayout.OnAppearing += appearingPosition =>
- {
- Controller.SendPositionAppearing(appearingPosition);
- };
-
- // disappearing
- _physicalLayout.OnDisappearing += disappearingPosition =>
- {
- Controller.SendPositionDisappearing(disappearingPosition);
-
- // animation completed
- if (!scrolling && !dragging)
- {
- _position = _physicalLayout.VisiblePositions().Single();
-
- OnPositionChanged();
- OnItemChanged();
- }
- };
-
- // adapter
- var adapter = new ItemViewAdapter(this);
- adapter.RegisterAdapterDataObserver(new PositionUpdater(this));
- recyclerView.SetAdapter(adapter);
- }
-
- ItemViewAdapter Adapter => (ItemViewAdapter)Control.GetAdapter();
- PhysicalLayoutManager LayoutManager => (PhysicalLayoutManager)Control.GetLayoutManager();
-
- void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
- {
- switch (e.Action)
- {
- case NotifyCollectionChangedAction.Add:
- Adapter.NotifyItemRangeInserted(
- positionStart: e.NewStartingIndex,
- itemCount: e.NewItems.Count
- );
- break;
-
- case NotifyCollectionChangedAction.Move:
- for (var i = 0; i < e.NewItems.Count; i++)
- Adapter.NotifyItemMoved(
- fromPosition: e.OldStartingIndex + i,
- toPosition: e.NewStartingIndex + i
- );
- break;
-
- case NotifyCollectionChangedAction.Remove:
- if (Controller.Count == 0)
- throw new InvalidOperationException("CarouselView must retain a least one item.");
-
- Adapter.NotifyItemRangeRemoved(
- positionStart: e.OldStartingIndex,
- itemCount: e.OldItems.Count
- );
- break;
-
- case NotifyCollectionChangedAction.Replace:
- Adapter.NotifyItemRangeChanged(
- positionStart: e.OldStartingIndex,
- itemCount: e.OldItems.Count
- );
- break;
-
- case NotifyCollectionChangedAction.Reset:
- Adapter.NotifyDataSetChanged();
- break;
-
- default:
- throw new Exception($"Enum value '{(int)e.Action}' is not a member of NotifyCollectionChangedAction enumeration.");
- }
- }
- ICarouselViewController Controller => Element;
- IVisualElementController VisualElementController => Element;
- void OnPositionChanged()
- {
- Element.Position = _position;
- Controller.SendSelectedPositionChanged(_position);
- }
- void OnItemChanged()
- {
- object item = ((IItemViewController)Element).GetItem(_position);
- Controller.SendSelectedItemChanged(item);
- }
- #endregion
-
- protected override void OnElementChanged(ElementChangedEventArgs<CarouselView> e)
- {
- base.OnElementChanged(e);
-
- CarouselView oldElement = e.OldElement;
- CarouselView newElement = e.NewElement;
- if (oldElement != null)
- {
- e.OldElement.CollectionChanged -= OnCollectionChanged;
- }
-
- if (newElement != null)
- {
- if (Control == null)
- {
- Initialize();
- }
-
- // initialize properties
- _position = Element.Position;
-
- // initialize events
- Element.CollectionChanged += OnCollectionChanged;
- }
- }
- protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
- {
- if (e.PropertyName == "Position" && _position != Element.Position)
- _physicalLayout.ScrollToPosition(Element.Position);
-
- base.OnElementPropertyChanged(sender, e);
- }
- protected override void OnLayout(bool changed, int left, int top, int right, int bottom)
- {
- int width = right - left;
- int height = bottom - top;
-
- LayoutManager.Layout(width, height);
-
- base.OnLayout(changed, left, top, right, bottom);
-
- Control.Measure(
- widthMeasureSpec: new MeasureSpecification(width, MeasureSpecificationType.Exactly),
- heightMeasureSpec: new MeasureSpecification(height, MeasureSpecificationType.Exactly)
- );
-
- Control.Layout(0, 0, width, height);
- }
- protected override Size MinimumSize()
- {
- return new Size(40, 40);
- }
- }
-
- // RecyclerView virtualizes indexes (adapter position <-> viewGroup child index)
- // PhysicalLayoutManager virtualizes location (regular layout <-> screen)
- internal class PhysicalLayoutManager : LayoutManager
- {
- // ObservableCollection is our public entryway to this method and it only supports single item removal
- internal const int MaxItemsRemoved = 1;
-
- internal struct DecoratedView
- {
- public static implicit operator AndroidView(DecoratedView view)
- {
- return view._view;
- }
-
- #region Fields
- readonly PhysicalLayoutManager _layout;
- readonly AndroidView _view;
- #endregion
-
- internal DecoratedView(
- PhysicalLayoutManager layout,
- AndroidView view)
- {
- _layout = layout;
- _view = view;
- }
-
- internal int Left => _layout.GetDecoratedLeft(_view);
- internal int Top => _layout.GetDecoratedTop(_view);
- internal int Bottom => _layout.GetDecoratedBottom(_view);
- internal int Right => _layout.GetDecoratedRight(_view);
- internal int Width => Right - Left;
- internal int Height => Bottom - Top;
- internal IntRectangle Rectangle => new IntRectangle(Left, Top, Width, Height);
-
- internal void Measure(int widthUsed, int heightUsed)
- {
- _layout.MeasureChild(_view, widthUsed, heightUsed);
- }
- internal void MeasureWithMargins(int widthUsed, int heightUsed)
- {
- _layout.MeasureChildWithMargins(_view, widthUsed, heightUsed);
- }
- internal void Layout(IntRectangle position)
- {
- var renderer = _view as IVisualElementRenderer;
- renderer.Element.Layout(position.ToFormsRectangle(_layout._context));
-
- // causes the private LAYOUT_REQUIRED flag to be set so we can be sure the Layout call will properly chain through to all children
- Measure(position.Width, position.Height);
- _layout.LayoutDecorated(_view,
- left: position.Left,
- top: position.Top,
- right: position.Right,
- bottom: position.Bottom
- );
- }
- internal void Add()
- {
- _layout.AddView(_view);
- }
- internal void DetachAndScrap(Recycler recycler)
- {
- _layout.DetachAndScrapView(_view, recycler);
- }
- }
- internal abstract class VirtualLayoutManager
- {
- internal abstract Tuple<int, int> GetPositions(
- int positionOrigin,
- int itemCount,
- IntRectangle viewport,
- bool isPreLayout
- );
-
- internal abstract IntRectangle LayoutItem(int positionOrigin, int position);
- internal abstract bool CanScrollHorizontally
- {
- get;
- }
- internal abstract bool CanScrollVertically
- {
- get;
- }
-
- internal abstract void Layout(int positionOrigin, IntSize viewportSize, ref IntVector offset);
- internal abstract IntRectangle GetBounds(int positionOrigin, State state);
- }
-
- #region Private Defintions
- enum AdapterChangeType
- {
- Removed = 1,
- Added,
- Moved,
- Updated,
- Changed
- }
- enum SnapPreference
- {
- None = 0,
- Begin = 1,
- End = -1
- }
- sealed class SeekAndSnapScroller : LinearSmoothScroller
- {
- #region Fields
- readonly SnapPreference _snapPreference;
- readonly Func<int, IntVector> _vectorToPosition;
- #endregion
-
- internal SeekAndSnapScroller(
- Context context,
- Func<int, IntVector> vectorToPosition,
- SnapPreference snapPreference = SnapPreference.None)
- : base(context)
- {
- _vectorToPosition = vectorToPosition;
- _snapPreference = snapPreference;
- }
-
- protected override int HorizontalSnapPreference => (int)_snapPreference;
- protected override void OnStart()
- {
- OnBeginScroll?.Invoke(TargetPosition);
- base.OnStart();
- }
- protected override void OnStop()
- {
- // expected this to be triggered with the animation stops but it
- // actually seems to be triggered when the target is found
- OnEndScroll?.Invoke(TargetPosition);
- base.OnStop();
- }
-
- public event Action<int> OnBeginScroll;
- public event Action<int> OnEndScroll;
-
- public override PointF ComputeScrollVectorForPosition(int targetPosition)
- {
- var vector = _vectorToPosition(targetPosition);
- return new PointF(vector.X, vector.Y);
- }
-
- }
- #endregion
-
- #region Static Fields
- readonly static int s_samplesCount = 5;
- #endregion
-
- #region Fields
- readonly Context _context;
- readonly VirtualLayoutManager _virtualLayout;
- readonly Queue<Action<Recycler, State>> _deferredLayout;
- readonly Dictionary<int, AndroidView> _viewByAdaptorPosition;
- readonly HashSet<int> _visibleAdapterPosition;
- readonly SeekAndSnapScroller _scroller;
-
- int _positionOrigin; // coordinates are relative to the upper left corner of this element
- IntVector _locationOffset; // upper left corner of screen is positionOrigin + locationOffset
- List<IntVector> _samples;
- AdapterChangeType _adapterChangeType;
- #endregion
-
- internal PhysicalLayoutManager(Context context, VirtualLayoutManager virtualLayout, int positionOrigin)
- {
- _positionOrigin = positionOrigin;
- _context = context;
- _virtualLayout = virtualLayout;
- _viewByAdaptorPosition = new Dictionary<int, AndroidView>();
- _visibleAdapterPosition = new HashSet<int>();
- _samples = Enumerable.Repeat(IntVector.Origin, s_samplesCount).ToList();
- _deferredLayout = new Queue<Action<Recycler, State>>();
- _scroller = new SeekAndSnapScroller(
- context: context,
- vectorToPosition: adapterPosition =>
- {
- var end = virtualLayout.LayoutItem(_positionOrigin, adapterPosition).Center();
- var begin = Viewport.Center();
- return end - begin;
- }
- );
-
- _scroller.OnBeginScroll += adapterPosition => OnBeginScroll?.Invoke(adapterPosition);
- _scroller.OnEndScroll += adapterPosition => OnEndScroll?.Invoke(adapterPosition);
- }
-
- #region Private Members
- // helpers to deal with locations as IntRectangles and IntVectors
- IntRectangle Rectangle => new IntRectangle(0, 0, Width, Height);
- void OffsetChildren(IntVector delta)
- {
- OffsetChildrenHorizontal(-delta.X);
- OffsetChildrenVertical(-delta.Y);
- }
- void ScrollBy(ref IntVector delta, Recycler recycler, State state)
- {
- _adapterChangeType = default(AdapterChangeType);
-
- delta = Viewport.BoundTranslation(
- delta: delta,
- bound: _virtualLayout.GetBounds(_positionOrigin, state)
- );
-
- _locationOffset += delta;
- _samples.Insert(0, delta);
- _samples.RemoveAt(_samples.Count - 1);
-
- OffsetChildren(delta);
- OnLayoutChildren(recycler, state);
- }
- void OnAppearingOrDisappearing(int position, bool isAppearing)
- {
- if (isAppearing)
- {
- if (!_visibleAdapterPosition.Contains(position))
- {
- _visibleAdapterPosition.Add(position);
- OnAppearing?.Invoke(position);
- }
- }
- else
- {
- if (_visibleAdapterPosition.Contains(position))
- {
- _visibleAdapterPosition.Remove(position);
- OnDisappearing?.Invoke(position);
- }
- }
- }
- #endregion
-
- protected override void Dispose(bool disposing)
- {
- base.Dispose(disposing);
- }
-
- internal event Action<int> OnAppearing;
- internal event Action<int> OnBeginScroll;
- internal event Action<int> OnDisappearing;
- internal event Action<int> OnEndScroll;
-
- internal IntVector Velocity => _samples.Aggregate((o, a) => o + a) / _samples.Count;
- internal void Layout(int width, int height)
- {
- // e.g. when rotated the width and height are updated the virtual layout will
- // need to resize and provide a new viewport offset given the current one.
- _virtualLayout.Layout(_positionOrigin, new IntSize(width, height), ref _locationOffset);
- }
- internal IntRectangle Viewport => Rectangle + _locationOffset;
- internal IEnumerable<int> VisiblePositions()
- {
- return _visibleAdapterPosition;
- }
- internal IEnumerable<AndroidView> Views()
- {
- return _viewByAdaptorPosition.Values;
- }
-
- public override void OnAdapterChanged(Adapter oldAdapter, Adapter newAdapter)
- {
- RemoveAllViews();
- }
- public override void OnItemsChanged(RecyclerView recyclerView)
- {
- _adapterChangeType = AdapterChangeType.Changed;
-
- // low-fidelity change event; assume everything has changed. If adapter reports it has "stable IDs" then
- // RecyclerView will attempt to synthesize high-fidelity change events: added, removed, moved, updated.
- base.OnItemsChanged(recyclerView);
- }
- public override void OnItemsAdded(RecyclerView recyclerView, int positionStart, int itemCount)
- {
- _adapterChangeType = AdapterChangeType.Added;
-
- _deferredLayout.Enqueue((recycler, state) =>
- {
-
- var viewByAdaptorPositionCopy = _viewByAdaptorPosition.ToArray();
- _viewByAdaptorPosition.Clear();
- foreach (KeyValuePair<int, AndroidView> pair in viewByAdaptorPositionCopy)
- {
- var view = pair.Value;
- var position = pair.Key;
-
- // position unchanged
- if (position < positionStart)
- _viewByAdaptorPosition[position] = view;
-
- // position changed
- else
- _viewByAdaptorPosition[position + itemCount] = view;
- }
-
- if (_positionOrigin >= positionStart)
- _positionOrigin += itemCount;
- });
- base.OnItemsAdded(recyclerView, positionStart, itemCount);
- }
- public override void OnItemsRemoved(RecyclerView recyclerView, int positionStart, int itemCount)
- {
- Assert(itemCount == MaxItemsRemoved);
- _adapterChangeType = AdapterChangeType.Removed;
-
- var positionEnd = positionStart + itemCount;
-
- _deferredLayout.Enqueue((recycler, state) =>
- {
- if (state.ItemCount == 0)
- throw new InvalidOperationException("Cannot delete all items.");
-
- // re-map views to their new positions
- var viewByAdaptorPositionCopy = _viewByAdaptorPosition.ToArray();
- _viewByAdaptorPosition.Clear();
- foreach (var pair in viewByAdaptorPositionCopy)
- {
- var view = pair.Value;
- var position = pair.Key;
-
- // position unchanged
- if (position < positionStart)
- _viewByAdaptorPosition[position] = view;
-
- // position changed
- else if (position >= positionEnd)
- _viewByAdaptorPosition[position - itemCount] = view;
-
- // removed
- else
- {
- _viewByAdaptorPosition[-1] = view;
- if (_visibleAdapterPosition.Contains(position))
- _visibleAdapterPosition.Remove(position);
- }
- }
-
- // if removed origin then shift origin to first removed position
- if (_positionOrigin >= positionStart && _positionOrigin < positionEnd)
- {
- _positionOrigin = positionStart;
-
- // if no items to right of removed origin then set origin to item prior to removed set
- if (_positionOrigin >= state.ItemCount)
- {
- _positionOrigin = state.ItemCount - 1;
-
- if (!_viewByAdaptorPosition.ContainsKey(_positionOrigin))
- throw new InvalidOperationException(
- "VirtualLayoutManager must add items to the left and right of the origin"
- );
- }
- }
-
- // if removed before origin then shift origin left
- else if (_positionOrigin >= positionEnd)
- _positionOrigin -= itemCount;
- });
-
- base.OnItemsRemoved(recyclerView, positionStart, itemCount);
- }
- public override void OnItemsMoved(RecyclerView recyclerView, int from, int toValue, int itemCount)
- {
- _adapterChangeType = AdapterChangeType.Moved;
- base.OnItemsMoved(recyclerView, from, toValue, itemCount);
- }
- public override void OnItemsUpdated(RecyclerView recyclerView, int positionStart, int itemCount)
- {
- _adapterChangeType = AdapterChangeType.Updated;
-
- // rebind rendered updated elements
- _deferredLayout.Enqueue((recycler, state) =>
- {
- for (var i = 0; i < itemCount; i++)
- {
- var position = positionStart + i;
-
- AndroidView view;
- if (!_viewByAdaptorPosition.TryGetValue(position, out view))
- continue;
-
- recycler.BindViewToPosition(view, position);
- }
- });
-
- base.OnItemsUpdated(recyclerView, positionStart, itemCount);
- }
-
- public override LayoutParams GenerateDefaultLayoutParams()
- {
- return new LayoutParams(ViewGroup.LayoutParams.WrapContent, ViewGroup.LayoutParams.WrapContent);
- }
- public override AndroidView FindViewByPosition(int adapterPosition)
- {
- // Used by SmoothScrollToPosition to know when the view
- // for the targeted adapterPosition has been attached.
-
- AndroidView view;
- if (!_viewByAdaptorPosition.TryGetValue(adapterPosition, out view))
- return null;
- return view;
- }
-
- public override void ScrollToPosition(int adapterPosition)
- {
- if (adapterPosition < 0 || adapterPosition >= ItemCount)
- throw new ArgumentException(nameof(adapterPosition));
-
- _scroller.TargetPosition = adapterPosition;
- StartSmoothScroll(_scroller);
- }
- public override void SmoothScrollToPosition(RecyclerView recyclerView, State state, int adapterPosition)
- {
- ScrollToPosition(adapterPosition);
- }
- public override bool CanScrollHorizontally() => _virtualLayout.CanScrollHorizontally;
- public override bool CanScrollVertically() => _virtualLayout.CanScrollVertically;
-
- // entry points
- public override bool SupportsPredictiveItemAnimations() => true;
- public override void OnLayoutChildren(Recycler recycler, State state)
- {
- var adapterChangeType = _adapterChangeType;
- if (state.IsPreLayout)
- adapterChangeType = default(AdapterChangeType);
-
- // adapter updates
- if (!state.IsPreLayout)
- {
- while (_deferredLayout.Count > 0)
- _deferredLayout.Dequeue()(recycler, state);
- }
-
- // get visible items
- var positions = _virtualLayout.GetPositions(
- positionOrigin: _positionOrigin,
- itemCount: state.ItemCount,
- viewport: Viewport,
- // IsPreLayout => some type of data update of yet unknown type. Must assume update
- // could be remove so virtualLayout must +1 off-screen left in case origin is
- // removed and +n off-screen right to slide onscreen if a big item is removed
- isPreLayout: state.IsPreLayout || adapterChangeType == AdapterChangeType.Removed
- ).ToRange();
-
- // disappearing
- var disappearing = _viewByAdaptorPosition.Keys.Except(positions).ToList();
-
- // defer cleanup of displaced items and lay them out off-screen so they animate off-screen
- if (adapterChangeType == AdapterChangeType.Added)
- {
- positions = positions.Concat(disappearing).OrderBy(o => o).ToArray();
- disappearing.Clear();
- }
-
- // recycle
- foreach (var position in disappearing)
- {
- var view = _viewByAdaptorPosition[position];
-
- // remove
- _viewByAdaptorPosition.Remove(position);
- OnAppearingOrDisappearing(position, false);
-
- // scrap
- new DecoratedView(this, view).DetachAndScrap(recycler);
- }
-
- // TODO: Generalize
- if (adapterChangeType == AdapterChangeType.Removed && _positionOrigin == state.ItemCount - 1)
- {
- var vlayout = _virtualLayout.LayoutItem(_positionOrigin, _positionOrigin);
- _locationOffset = new IntVector(vlayout.Width - Width, _locationOffset.Y);
- }
-
- var nextLocationOffset = new IntPoint(int.MaxValue, int.MaxValue);
- var nextPositionOrigin = int.MaxValue;
- foreach (var position in positions)
- {
- // attach
- AndroidView view;
- if (!_viewByAdaptorPosition.TryGetValue(position, out view))
- AddView(_viewByAdaptorPosition[position] = view = recycler.GetViewForPosition(position));
-
- // layout
- var decoratedView = new DecoratedView(this, view);
- var layout = _virtualLayout.LayoutItem(_positionOrigin, position);
- var physicalLayout = layout - _locationOffset;
- decoratedView.Layout(physicalLayout);
-
- var isVisible = Viewport.IntersectsWith(layout);
- if (isVisible)
- OnAppearingOrDisappearing(position, true);
-
- // update offsets
- if (isVisible && position < nextPositionOrigin)
- {
- nextLocationOffset = layout.Location;
- nextPositionOrigin = position;
- }
- }
-
- // update origin
- if (nextPositionOrigin != int.MaxValue)
- {
- _positionOrigin = nextPositionOrigin;
- _locationOffset -= (IntVector)nextLocationOffset;
- }
-
- // scrapped views not re-attached must be recycled (why isn't this done by Android, I dunno)
- foreach (var viewHolder in recycler.ScrapList.ToArray())
- recycler.RecycleView(viewHolder.ItemView);
- }
-
- public override int ScrollHorizontallyBy(int dx, Recycler recycler, State state)
- {
- var delta = new IntVector(dx, 0);
- ScrollBy(ref delta, recycler, state);
- return delta.X;
- }
- public override int ScrollVerticallyBy(int dy, Recycler recycler, State state)
- {
- var delta = new IntVector(0, dy);
- ScrollBy(ref delta, recycler, state);
- return delta.Y;
- }
-
- public override string ToString()
- {
- return $"offset={_locationOffset}";
- }
- }
-
- internal class ItemViewAdapter : Adapter
- {
- #region Private Definitions
- class CarouselViewHolder : ViewHolder
- {
- #region Fields
- readonly View _view;
- readonly IVisualElementRenderer _visualElementRenderer;
- #endregion
-
- public CarouselViewHolder(View view, IVisualElementRenderer renderer)
- : base(renderer.ViewGroup)
- {
- _visualElementRenderer = renderer;
- _view = view;
- }
-
- public View View => _view;
- public IVisualElementRenderer VisualElementRenderer => _visualElementRenderer;
- }
- #endregion
-
- #region Fields
- readonly IVisualElementRenderer _renderer;
- readonly Dictionary<int, object> _typeByTypeId;
- readonly Dictionary<object, int> _typeIdByType;
- int _nextItemTypeId;
- #endregion
-
- public ItemViewAdapter(IVisualElementRenderer carouselRenderer)
- {
- _renderer = carouselRenderer;
- _typeByTypeId = new Dictionary<int, object>();
- _typeIdByType = new Dictionary<object, int>();
- _nextItemTypeId = 0;
- }
-
- #region Private Members
- ItemsView Element
- {
- get
- {
- return (ItemsView)_renderer.Element;
- }
- }
- IItemViewController Controller
- {
- get
- {
- return Element;
- }
- }
- #endregion
-
- public override int ItemCount
- {
- get
- {
- return Controller.Count;
- }
- }
- public override int GetItemViewType(int position)
- {
- // get item and type from ItemSource and ItemTemplate
- object item = Controller.GetItem(position);
- object type = Controller.GetItemType(item);
-
- // map type as DataTemplate to type as Id
- int id = default(int);
- if (!_typeIdByType.TryGetValue(type, out id))
- {
- id = _nextItemTypeId++;
- _typeByTypeId[id] = type;
- _typeIdByType[type] = id;
- }
- return id;
- }
- public override ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
- {
- // create view from type
- var type = _typeByTypeId[viewType];
- var view = Controller.CreateView(type);
-
- // create renderer for view
- var renderer = Platform.CreateRenderer(view);
- Platform.SetRenderer(view, renderer);
-
- // package renderer + view
- return new CarouselViewHolder(view, renderer);
- }
- public override void OnBindViewHolder(ViewHolder holder, int position)
- {
- var carouselHolder = (CarouselViewHolder)holder;
-
- var item = Controller.GetItem(position);
- Controller.BindView(carouselHolder.View, item);
- }
- }
-} \ No newline at end of file
diff --git a/Xamarin.Forms.Platform.Android/Xamarin.Forms.Platform.Android.csproj b/Xamarin.Forms.Platform.Android/Xamarin.Forms.Platform.Android.csproj
index 44bac817..4c8351bd 100644
--- a/Xamarin.Forms.Platform.Android/Xamarin.Forms.Platform.Android.csproj
+++ b/Xamarin.Forms.Platform.Android/Xamarin.Forms.Platform.Android.csproj
@@ -150,7 +150,6 @@
<Compile Include="LayoutExtensions.cs" />
<Compile Include="Renderers\AHorizontalScrollView.cs" />
<Compile Include="Renderers\ButtonDrawable.cs" />
- <Compile Include="Renderers\CarouselViewRenderer.cs" />
<Compile Include="Renderers\AlignmentExtensions.cs" />
<Compile Include="IStartActivityForResult.cs" />
<Compile Include="Renderers\ConditionalFocusLayout.cs" />