diff options
Diffstat (limited to 'Xamarin.Forms.Platform.Android/Renderers/CarouselPageAdapter.cs')
| -rw-r--r-- | Xamarin.Forms.Platform.Android/Renderers/CarouselPageAdapter.cs | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/Xamarin.Forms.Platform.Android/Renderers/CarouselPageAdapter.cs b/Xamarin.Forms.Platform.Android/Renderers/CarouselPageAdapter.cs new file mode 100644 index 00000000..345501d5 --- /dev/null +++ b/Xamarin.Forms.Platform.Android/Renderers/CarouselPageAdapter.cs @@ -0,0 +1,155 @@ +using System; +using System.Collections.Specialized; +using System.Linq; +using Android.Content; +using Android.Support.V4.View; +using Android.Views; +using Object = Java.Lang.Object; + +namespace Xamarin.Forms.Platform.Android +{ + internal class CarouselPageAdapter : PagerAdapter, ViewPager.IOnPageChangeListener + { + readonly Context _context; + readonly ViewPager _pager; + bool _ignoreAndroidSelection; + CarouselPage _page; + + public CarouselPageAdapter(ViewPager pager, CarouselPage page, Context context) + { + _pager = pager; + _page = page; + _context = context; + + page.PagesChanged += OnPagesChanged; + } + + public override int Count + { + get { return _page.Children.Count(); } + } + + public void OnPageScrolled(int position, float positionOffset, int positionOffsetPixels) + { + } + + public void OnPageScrollStateChanged(int state) + { + } + + public void OnPageSelected(int position) + { + if (_ignoreAndroidSelection) + return; + + int currentItem = _pager.CurrentItem; + _page.CurrentPage = currentItem >= 0 && currentItem < _page.LogicalChildren.Count ? _page.LogicalChildren[currentItem] as ContentPage : null; + } + + public override void DestroyItem(ViewGroup p0, int p1, Object p2) + { + var holder = (ObjectJavaBox<Tuple<ViewGroup, Page, int>>)p2; + Page destroyedPage = holder.Instance.Item2; + + IVisualElementRenderer renderer = Platform.GetRenderer(destroyedPage); + renderer.ViewGroup.RemoveFromParent(); + holder.Instance.Item1.RemoveFromParent(); + } + + public override int GetItemPosition(Object item) + { + // The int is the current index. + var holder = (ObjectJavaBox<Tuple<ViewGroup, Page, int>>)item; + Element parent = holder.Instance.Item2.RealParent; + if (parent == null) + return PositionNone; + + // Unfortunately we can't just call CarouselPage.GetIndex, because we need to know + // if the item has been removed. We could update MultiPage<T> to set removed items' index + // to -1 to support this if it ever becomes an issue. + int index = ((CarouselPage)parent).Children.IndexOf(holder.Instance.Item2); + if (index == -1) + return PositionNone; + + if (index != holder.Instance.Item3) + { + holder.Instance = new Tuple<ViewGroup, Page, int>(holder.Instance.Item1, holder.Instance.Item2, index); + return index; + } + + return PositionUnchanged; + } + + public override Object InstantiateItem(ViewGroup container, int position) + { + ContentPage child = _page.Children.ElementAt(position); + if (Platform.GetRenderer(child) == null) + Platform.SetRenderer(child, Platform.CreateRenderer(child)); + + IVisualElementRenderer renderer = Platform.GetRenderer(child); + renderer.ViewGroup.RemoveFromParent(); + + ViewGroup frame = new PageContainer(_context, renderer); + + container.AddView(frame); + + return new ObjectJavaBox<Tuple<ViewGroup, Page, int>>(new Tuple<ViewGroup, Page, int>(frame, child, position)); + } + + public override bool IsViewFromObject(global::Android.Views.View p0, Object p1) + { + var holder = (ObjectJavaBox<Tuple<ViewGroup, Page, int>>)p1; + ViewGroup frame = holder.Instance.Item1; + return p0 == frame; + } + + public void UpdateCurrentItem() + { + if (_page.CurrentPage == null) + throw new InvalidOperationException("CarouselPage has no children."); + + int index = CarouselPage.GetIndex(_page.CurrentPage); + if (index >= 0 && index < _page.Children.Count) + _pager.CurrentItem = index; + } + + protected override void Dispose(bool disposing) + { + if (disposing && _page != null) + { + foreach (Element element in _page.LogicalChildren) + { + var childPage = element as VisualElement; + + if (childPage == null) + continue; + + IVisualElementRenderer childPageRenderer = Platform.GetRenderer(childPage); + if (childPageRenderer != null) + { + childPageRenderer.ViewGroup.RemoveFromParent(); + childPageRenderer.Dispose(); + Platform.SetRenderer(childPage, null); + } + } + _page.PagesChanged -= OnPagesChanged; + _page = null; + } + base.Dispose(disposing); + } + + void OnPagesChanged(object sender, NotifyCollectionChangedEventArgs e) + { + _ignoreAndroidSelection = true; + + NotifyDataSetChanged(); + + _ignoreAndroidSelection = false; + + if (_page.CurrentPage == null) + return; + + UpdateCurrentItem(); + } + } +}
\ No newline at end of file |