CarouselViewRendererFix for iOS

CarouselViewRendererFix.cs

using CoreGraphics;
using System;
using System.Reflection;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;
[assembly: ExportRenderer(typeof(CarouselView), typeof(YourNameSpace.iOS.Renderers.CarouselViewRendererFix))]
namespace YourNameSpace.iOS.Renderers
{
    // this is an implementation of this pull request: https://github.com/xamarin/Xamarin.Forms.CarouselView/pull/13/files
    public class CarouselViewRendererFix : Xamarin.Forms.Platform.CarouselViewRenderer
    {
        private CGRect? _lastBounds;
        private UICollectionViewController _controller = null;
        private MethodInfo _controllerReloadDataMethod = null;
        private MethodInfo _controllerScrollToPositionMethod = null;
        private Type _controllerType = null;
        
        /// <summary>
        /// The underlying controller of the view
        /// </summary>
        protected UICollectionViewController Controller
        {
            get
            {
                if (_controller == null)
                {
                    FieldInfo fi = typeof(Xamarin.Forms.Platform.CarouselViewRenderer).GetField(nameof(_controller), BindingFlags.NonPublic | BindingFlags.Instance);
                    object cvc = fi?.GetValue(this);
                    _controller = (UICollectionViewController)cvc;
                }
                return _controller;
            }
        }
        /// <summary>
        /// The underlying controller has an internal type, so I have to get it by reflection
        /// </summary>
        protected Type ControllerType
        {
            get
            {
                if (_controllerType == null)
                {
                    _controllerType = Controller?.GetType();
                }
                return _controllerType;
            }
        }
        /// <summary>
        /// The method that reloads the data on the Controller, it is an internal method so I have to get it by reflection
        /// </summary>
        protected MethodInfo ControllerReloadDataMethod
        {
            get
            {
                if (_controllerReloadDataMethod == null)
                {
                    _controllerReloadDataMethod = ControllerType?.GetMethod(nameof(ReloadData), BindingFlags.Instance | BindingFlags.NonPublic);
                }
                return _controllerReloadDataMethod;
            }
        }
        /// <summary>
        /// The method that scrolls to position on the Controller, it is an internal method so I have to get it by reflection
        /// </summary>
        protected MethodInfo ControllerScrollToPositionMethod
        {
            get
            {
                if (_controllerScrollToPositionMethod == null)
                {
                    _controllerScrollToPositionMethod = ControllerType?.GetMethod(nameof(ScrollToPosition), BindingFlags.Instance | BindingFlags.NonPublic);
                }
                return _controllerScrollToPositionMethod;
            }
        }
        /// <summary>
        /// Reload the data in the controller
        /// </summary>
        /// <param name="position">current position in the data</param>
        protected void ReloadData(int position)
        {
            var parameters = new object[1];
            parameters[0] = position;
            ControllerReloadDataMethod?.Invoke(Controller, parameters);
        }
        /// <summary>
        /// Scroll to a position on the controller
        /// </summary>
        /// <param name="position">position to scroll to</param>
        /// <param name="animate">show animations when scrolling</param>
        protected void ScrollToPosition(int position, bool animate)
        {
            var parameters = new object[2];
            parameters[0] = position;
            parameters[1] = animate;
            ControllerScrollToPositionMethod?.Invoke(Controller, parameters);
        }
        /// <summary>
        /// This override will adjust the layout on rotation (code in the base implementation doesn't work)
        /// </summary>
        public override void LayoutSubviews()
        {
            bool? wasPortrait = null;
            if ( _lastBounds != null )
            {
                wasPortrait = _lastBounds.Value.Height > _lastBounds.Value.Width;
            }
            base.LayoutSubviews();
            var nowPortrait = Bounds.Height > Bounds.Width;
            if ( wasPortrait == null || wasPortrait != nowPortrait )
            {
                ScrollToPosition(Element.Position, false);
            }
            _lastBounds = Bounds;
        }
        /// <summary>
        /// This forces reload of the data when the Element Changes
        /// </summary>
        /// <param name="e"></param>
        protected override void OnElementChanged(ElementChangedEventArgs<CarouselView> e)
        {
            base.OnElementChanged(e);
            if (e.NewElement != null)
            {
                ReloadData(Element.Position);
            }
        }
        /// <summary>
        /// Cleans up the controller and control
        /// </summary>
        /// <param name="disposing"></param>
        protected override void Dispose(bool disposing)
        {
            var control = Control;
            base.Dispose(disposing);
            if ( disposing )
            {
                if( Controller != null)
                {
                    Controller.Dispose();
                }
                if (control != null)
                {
                    control.Dispose();
                }
            }
        }
    }
}