зеркало из https://github.com/DeGsoft/maui-linux.git
815 строки
23 KiB
C#
815 строки
23 KiB
C#
using System;
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using System.Collections;
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using System.Collections.Generic;
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using System.Collections.Specialized;
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using System.ComponentModel;
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using System.Linq;
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using System.Threading.Tasks;
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using Windows.Foundation;
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using Windows.UI.Xaml;
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using Windows.UI.Xaml.Automation.Peers;
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using Windows.UI.Xaml.Controls;
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using Windows.UI.Xaml.Data;
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using Windows.UI.Xaml.Input;
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using Windows.UI.Xaml.Media;
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using WListView = Windows.UI.Xaml.Controls.ListView;
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using WBinding = Windows.UI.Xaml.Data.Binding;
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using WApp = Windows.UI.Xaml.Application;
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using Xamarin.Forms.Internals;
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using Xamarin.Forms.PlatformConfiguration.WindowsSpecific;
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using Specifics = Xamarin.Forms.PlatformConfiguration.WindowsSpecific.ListView;
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using System.Collections.ObjectModel;
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using UwpScrollBarVisibility = Windows.UI.Xaml.Controls.ScrollBarVisibility;
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using WSelectionChangedEventArgs = Windows.UI.Xaml.Controls.SelectionChangedEventArgs;
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namespace Xamarin.Forms.Platform.UWP
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{
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public class ListViewRenderer : ViewRenderer<ListView, FrameworkElement>
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{
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ITemplatedItemsView<Cell> TemplatedItemsView => Element;
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bool _collectionIsWrapped;
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IList _collection = null;
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bool _itemWasClicked;
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bool _subscribedToItemClick;
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bool _subscribedToTapped;
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bool _disposed;
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CollectionViewSource _collectionViewSource;
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UwpScrollBarVisibility? _defaultHorizontalScrollVisibility;
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UwpScrollBarVisibility? _defaultVerticalScrollVisibility;
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protected WListView List { get; private set; }
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protected class ListViewTransparent : WListView
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{
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public ListViewTransparent() : base() { }
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// Container is not created when the item is null.
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// To prevent this, base container preparationan receives an empty object.
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protected override void PrepareContainerForItemOverride(DependencyObject element, object item)
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=> base.PrepareContainerForItemOverride(element, item ?? new object());
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}
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protected override void OnElementChanged(ElementChangedEventArgs<ListView> e)
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{
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base.OnElementChanged(e);
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if (e.OldElement != null)
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{
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e.OldElement.ItemSelected -= OnElementItemSelected;
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e.OldElement.ScrollToRequested -= OnElementScrollToRequested;
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((ITemplatedItemsView<Cell>)e.OldElement).TemplatedItems.CollectionChanged -= OnCollectionChanged;
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if (Control != null)
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{
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Control.Loaded -= ControlOnLoaded;
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}
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}
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if (e.NewElement != null)
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{
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e.NewElement.ItemSelected += OnElementItemSelected;
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e.NewElement.ScrollToRequested += OnElementScrollToRequested;
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((ITemplatedItemsView<Cell>)e.NewElement).TemplatedItems.CollectionChanged += OnCollectionChanged;
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if (List == null)
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{
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List = new ListViewTransparent
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{
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IsSynchronizedWithCurrentItem = false,
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ItemTemplate = (Windows.UI.Xaml.DataTemplate)WApp.Current.Resources["CellTemplate"],
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HeaderTemplate = (Windows.UI.Xaml.DataTemplate)WApp.Current.Resources["View"],
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FooterTemplate = (Windows.UI.Xaml.DataTemplate)WApp.Current.Resources["View"],
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ItemContainerStyle = (Windows.UI.Xaml.Style)WApp.Current.Resources["FormsListViewItem"],
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GroupStyleSelector = (GroupStyleSelector)WApp.Current.Resources["ListViewGroupSelector"]
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};
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List.SelectionChanged += OnControlSelectionChanged;
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}
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ReloadData();
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UpdateGrouping();
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UpdateHeader();
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UpdateFooter();
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UpdateSelectionMode();
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UpdateWindowsSpecificSelectionMode();
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ClearSizeEstimate();
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UpdateVerticalScrollBarVisibility();
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UpdateHorizontalScrollBarVisibility();
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if (Control != null)
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{
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Control.Loaded += ControlOnLoaded;
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}
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}
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}
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void ControlOnLoaded(object sender, RoutedEventArgs e)
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{
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var scrollViewer = GetScrollViewer();
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scrollViewer?.RegisterPropertyChangedCallback(ScrollViewer.VerticalOffsetProperty, (o, dp) =>
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{
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var args = new ScrolledEventArgs(0, _scrollViewer.VerticalOffset);
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Element?.SendScrolled(args);
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});
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}
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bool IsObservableCollection(object source)
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{
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var type = source.GetType();
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return type.IsGenericType &&
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type.GetGenericTypeDefinition() == typeof(ObservableCollection<>);
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}
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void ReloadData()
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{
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if (Element?.ItemsSource == null)
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{
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_collection = null;
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}
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else
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{
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_collectionIsWrapped = !IsObservableCollection(Element.ItemsSource);
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if (_collectionIsWrapped)
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{
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_collection = new ObservableCollection<object>();
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foreach (var item in Element.ItemsSource)
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_collection.Add(item);
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}
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else
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{
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_collection = (IList)Element.ItemsSource;
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}
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}
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if (_collectionViewSource != null)
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_collectionViewSource.Source = null;
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_collectionViewSource = new CollectionViewSource
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{
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Source = _collection,
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IsSourceGrouped = Element.IsGroupingEnabled
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};
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List.ItemsSource = _collectionViewSource.View;
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}
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void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
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{
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if (_collectionIsWrapped && _collection != null)
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{
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switch (e.Action)
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{
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case NotifyCollectionChangedAction.Add:
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if (e.NewStartingIndex < 0)
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goto case NotifyCollectionChangedAction.Reset;
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// if a NewStartingIndex that's too high is passed in just add the items.
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// I realize this is enforcing bad behavior but prior to this synchronization
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// code being added it wouldn't cause the app to crash whereas now it does
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// so this code accounts for that in order to ensure smooth sailing for the user
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if (e.NewStartingIndex >= _collection.Count)
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{
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for (int i = 0; i < e.NewItems.Count; i++)
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_collection.Add((e.NewItems[i] as BindableObject).BindingContext);
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}
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else
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{
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for (int i = e.NewItems.Count - 1; i >= 0; i--)
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_collection.Insert(e.NewStartingIndex, (e.NewItems[i] as BindableObject).BindingContext);
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}
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break;
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case NotifyCollectionChangedAction.Remove:
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for (int i = e.OldItems.Count - 1; i >= 0; i--)
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_collection.RemoveAt(e.OldStartingIndex);
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break;
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case NotifyCollectionChangedAction.Move:
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{
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var collection = (ObservableCollection<object>)_collection;
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for (var i = 0; i < e.OldItems.Count; i++)
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{
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var oldi = e.OldStartingIndex;
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var newi = e.NewStartingIndex;
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if (e.NewStartingIndex < e.OldStartingIndex)
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{
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oldi += i;
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newi += i;
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}
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collection.Move(oldi, newi);
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}
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}
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break;
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case NotifyCollectionChangedAction.Replace:
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{
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var collection = (ObservableCollection<object>)_collection;
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var newi = e.NewStartingIndex;
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for (var i = 0; i < e.NewItems.Count; i++)
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{
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newi += i;
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collection[newi] = (e.NewItems[i] as BindableObject).BindingContext;
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}
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}
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break;
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case NotifyCollectionChangedAction.Reset:
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default:
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ClearSizeEstimate();
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ReloadData();
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break;
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}
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}
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else if (e.Action == NotifyCollectionChangedAction.Reset)
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{
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ClearSizeEstimate();
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ReloadData();
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}
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if (Element.Dispatcher == null)
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Device.BeginInvokeOnMainThread(() => List?.UpdateLayout());
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else
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Element.Dispatcher.BeginInvokeOnMainThread(() => List?.UpdateLayout());
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}
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protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
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{
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base.OnElementPropertyChanged(sender, e);
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if (e.PropertyName == ListView.IsGroupingEnabledProperty.PropertyName)
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{
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UpdateGrouping();
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}
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else if (e.PropertyName == ListView.HeaderProperty.PropertyName || e.PropertyName == "HeaderElement")
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{
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UpdateHeader();
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}
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else if (e.PropertyName == ListView.FooterProperty.PropertyName || e.PropertyName == "FooterElement")
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{
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UpdateFooter();
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}
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else if (e.PropertyName == ListView.RowHeightProperty.PropertyName)
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{
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ClearSizeEstimate();
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}
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else if (e.PropertyName == ListView.HasUnevenRowsProperty.PropertyName)
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{
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ClearSizeEstimate();
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}
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else if (e.PropertyName == ListView.ItemTemplateProperty.PropertyName)
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{
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ClearSizeEstimate();
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}
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else if (e.PropertyName == ListView.SelectionModeProperty.PropertyName)
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{
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UpdateSelectionMode();
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}
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else if (e.PropertyName == Specifics.SelectionModeProperty.PropertyName)
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{
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UpdateWindowsSpecificSelectionMode();
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}
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else if (e.PropertyName == ListView.VerticalScrollBarVisibilityProperty.PropertyName)
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{
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UpdateVerticalScrollBarVisibility();
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}
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else if (e.PropertyName == ListView.HorizontalScrollBarVisibilityProperty.PropertyName)
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{
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UpdateHorizontalScrollBarVisibility();
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}
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}
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protected override void Dispose(bool disposing)
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{
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if (_disposed)
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{
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return;
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}
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_disposed = true;
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if (disposing)
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{
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if (List != null)
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{
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foreach (ViewToRendererConverter.WrapperControl wrapperControl in FindDescendants<ViewToRendererConverter.WrapperControl>(List))
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{
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wrapperControl.CleanUp();
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}
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if (_subscribedToTapped)
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{
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_subscribedToTapped = false;
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List.Tapped -= ListOnTapped;
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}
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if (_subscribedToItemClick)
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{
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_subscribedToItemClick = false;
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List.ItemClick -= OnListItemClicked;
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}
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List.SelectionChanged -= OnControlSelectionChanged;
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if (_collectionViewSource != null)
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_collectionViewSource.Source = null;
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List.DataContext = null;
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// Leaving this here as a warning because setting this to null causes
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// an AccessViolationException if you run Issue1975
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// List.ItemsSource = null;
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List = null;
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}
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if (_zoom != null)
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{
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_zoom.ViewChangeCompleted -= OnViewChangeCompleted;
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_zoom = null;
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}
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}
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base.Dispose(disposing);
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}
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static IEnumerable<T> FindDescendants<T>(DependencyObject dobj) where T : DependencyObject
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{
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int count = VisualTreeHelper.GetChildrenCount(dobj);
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for (var i = 0; i < count; i++)
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{
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DependencyObject element = VisualTreeHelper.GetChild(dobj, i);
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if (element is T)
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yield return (T)element;
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foreach (T descendant in FindDescendants<T>(element))
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yield return descendant;
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}
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}
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sealed class BrushedElement
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{
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public BrushedElement(FrameworkElement element, WBinding brushBinding = null, Brush brush = null)
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{
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Element = element;
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BrushBinding = brushBinding;
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Brush = brush;
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}
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public Brush Brush { get; }
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public WBinding BrushBinding { get; }
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public FrameworkElement Element { get; }
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public bool IsBound
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{
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get { return BrushBinding != null; }
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}
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}
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SemanticZoom _zoom;
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ScrollViewer _scrollViewer;
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ContentControl _headerControl;
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readonly List<BrushedElement> _highlightedElements = new List<BrushedElement>();
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void ClearSizeEstimate()
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{
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Element.ClearValue(CellControl.MeasuredEstimateProperty);
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}
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void UpdateFooter()
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{
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List.Footer = Element.FooterElement;
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}
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void UpdateHeader()
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{
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List.Header = Element.HeaderElement;
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}
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void UpdateGrouping()
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{
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bool grouping = Element.IsGroupingEnabled;
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if (_collectionViewSource != null)
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_collectionViewSource.IsSourceGrouped = grouping;
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var templatedItems = TemplatedItemsView.TemplatedItems;
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if (grouping && templatedItems.ShortNames != null)
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{
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if (_zoom == null)
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{
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ScrollViewer.SetIsVerticalScrollChainingEnabled(List, false);
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var grid = new GridView { ItemsSource = templatedItems.ShortNames, Style = (Windows.UI.Xaml.Style)WApp.Current.Resources["JumpListGrid"] };
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ScrollViewer.SetIsHorizontalScrollChainingEnabled(grid, false);
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_zoom = new SemanticZoom { IsZoomOutButtonEnabled = false, ZoomedOutView = grid };
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// Since we reuse our ScrollTo, we have to wait until the change completes or ChangeView has odd behavior.
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_zoom.ViewChangeCompleted += OnViewChangeCompleted;
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// Specific order to let SNC unparent the ListView for us
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SetNativeControl(_zoom);
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_zoom.ZoomedInView = List;
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}
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else
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{
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_zoom.CanChangeViews = true;
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}
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}
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else
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{
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if (_zoom != null)
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_zoom.CanChangeViews = false;
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else if (List != Control)
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SetNativeControl(List);
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}
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}
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void UpdateSelectionMode()
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{
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if (Element.SelectionMode == ListViewSelectionMode.None)
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{
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List.SelectionMode = Windows.UI.Xaml.Controls.ListViewSelectionMode.None;
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List.SelectedIndex = -1;
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Element.SelectedItem = null;
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}
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else if (Element.SelectionMode == ListViewSelectionMode.Single)
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{
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List.SelectionMode = Windows.UI.Xaml.Controls.ListViewSelectionMode.Single;
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// UWP seems to reset the selected item when SelectionMode is set, make sure our items stays selected by doing this call
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if (Element.SelectedItem != null)
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OnElementItemSelected(null, new SelectedItemChangedEventArgs(Element.SelectedItem, TemplatedItemsView.TemplatedItems.GetGlobalIndexOfItem(Element.SelectedItem)));
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}
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}
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void UpdateWindowsSpecificSelectionMode()
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{
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if (Element.OnThisPlatform().GetSelectionMode() == PlatformConfiguration.WindowsSpecific.ListViewSelectionMode.Accessible)
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{
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// Using Tapped will disable the ability to use the Enter key
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List.IsItemClickEnabled = true;
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if (!_subscribedToItemClick)
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{
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_subscribedToItemClick = true;
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List.ItemClick += OnListItemClicked;
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}
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if (_subscribedToTapped)
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{
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_subscribedToTapped = false;
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List.Tapped -= ListOnTapped;
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}
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}
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else
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{
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// In order to support tapping on elements within a list item, we handle
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// ListView.Tapped (which can be handled by child elements in the list items
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// and prevented from bubbling up) rather than ListView.ItemClick
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if (!_subscribedToTapped)
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{
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_subscribedToTapped = true;
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List.Tapped += ListOnTapped;
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}
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List.IsItemClickEnabled = false;
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if (_subscribedToItemClick)
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{
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_subscribedToItemClick = false;
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List.ItemClick -= OnListItemClicked;
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}
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}
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}
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void UpdateVerticalScrollBarVisibility()
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{
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if (_defaultVerticalScrollVisibility == null)
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_defaultVerticalScrollVisibility = ScrollViewer.GetVerticalScrollBarVisibility(Control);
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switch (Element.VerticalScrollBarVisibility)
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{
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case (ScrollBarVisibility.Always):
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ScrollViewer.SetVerticalScrollBarVisibility(Control, UwpScrollBarVisibility.Visible);
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break;
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case (ScrollBarVisibility.Never):
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ScrollViewer.SetVerticalScrollBarVisibility(Control, UwpScrollBarVisibility.Hidden);
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break;
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case (ScrollBarVisibility.Default):
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ScrollViewer.SetVerticalScrollBarVisibility(Control, (UwpScrollBarVisibility)_defaultVerticalScrollVisibility);
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break;
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}
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}
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void UpdateHorizontalScrollBarVisibility()
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{
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if (_defaultHorizontalScrollVisibility == null)
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_defaultHorizontalScrollVisibility = ScrollViewer.GetHorizontalScrollBarVisibility(Control);
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switch (Element.HorizontalScrollBarVisibility)
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{
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case (ScrollBarVisibility.Always):
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ScrollViewer.SetHorizontalScrollBarVisibility(Control, UwpScrollBarVisibility.Visible);
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break;
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case (ScrollBarVisibility.Never):
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ScrollViewer.SetHorizontalScrollBarVisibility(Control, UwpScrollBarVisibility.Hidden);
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break;
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case (ScrollBarVisibility.Default):
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ScrollViewer.SetHorizontalScrollBarVisibility(Control, (UwpScrollBarVisibility)_defaultHorizontalScrollVisibility);
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break;
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}
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}
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async void OnViewChangeCompleted(object sender, SemanticZoomViewChangedEventArgs e)
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{
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if (e.IsSourceZoomedInView)
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return;
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// HACK: Technically more than one short name could be the same, this will potentially find the wrong one in that case
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var item = (string)e.SourceItem.Item;
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var templatedItems = TemplatedItemsView.TemplatedItems;
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int index = templatedItems.ShortNames.IndexOf(item);
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if (index == -1)
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return;
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var til = templatedItems.GetGroup(index);
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if (til.Count == 0)
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return; // FIXME
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// Delay until after the SemanticZoom change _actually_ finishes, fixes tons of odd issues on Phone w/ virtualization.
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if (Device.Idiom == TargetIdiom.Phone)
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await Task.Delay(1);
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IListProxy listProxy = til.ListProxy;
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ScrollTo(listProxy.ProxiedEnumerable, listProxy[0], ScrollToPosition.Start, true, true);
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}
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bool ScrollToItemWithAnimation(ScrollViewer viewer, object item)
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{
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var selectorItem = List.ContainerFromItem(item) as Windows.UI.Xaml.Controls.Primitives.SelectorItem;
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var transform = selectorItem?.TransformToVisual(viewer.Content as UIElement);
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var position = transform?.TransformPoint(new Windows.Foundation.Point(0, 0));
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if (!position.HasValue)
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return false;
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// scroll with animation
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viewer.ChangeView(position.Value.X, position.Value.Y, null);
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return true;
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}
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#pragma warning disable 1998 // considered for removal
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async void ScrollTo(object group, object item, ScrollToPosition toPosition, bool shouldAnimate, bool includeGroup = false, bool previouslyFailed = false)
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#pragma warning restore 1998
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{
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ScrollViewer viewer = GetScrollViewer();
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if (viewer == null)
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{
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RoutedEventHandler loadedHandler = null;
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loadedHandler = async (o, e) =>
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{
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List.Loaded -= loadedHandler;
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// Here we try to avoid an exception, see explanation at bottom
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await Dispatcher.RunIdleAsync(args => { ScrollTo(group, item, toPosition, shouldAnimate, includeGroup); });
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};
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List.Loaded += loadedHandler;
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return;
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}
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var templatedItems = TemplatedItemsView.TemplatedItems;
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Tuple<int, int> location = templatedItems.GetGroupAndIndexOfItem(group, item);
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if (location.Item1 == -1 || location.Item2 == -1)
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return;
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object[] t = templatedItems.GetGroup(location.Item1).ItemsSource.Cast<object>().ToArray();
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object c = t[location.Item2];
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// scroll to desired item with animation
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if (shouldAnimate && ScrollToItemWithAnimation(viewer, c))
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return;
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double viewportHeight = viewer.ViewportHeight;
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var semanticLocation = new SemanticZoomLocation { Item = c };
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// async scrolling
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await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
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{
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switch (toPosition)
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{
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case ScrollToPosition.Start:
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{
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List.ScrollIntoView(c, ScrollIntoViewAlignment.Leading);
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return;
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}
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case ScrollToPosition.MakeVisible:
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{
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List.ScrollIntoView(c, ScrollIntoViewAlignment.Default);
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return;
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}
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case ScrollToPosition.End:
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case ScrollToPosition.Center:
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{
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var content = (FrameworkElement)List.ItemTemplate.LoadContent();
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content.DataContext = c;
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content.Measure(new Windows.Foundation.Size(viewer.ActualWidth, double.PositiveInfinity));
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double tHeight = content.DesiredSize.Height;
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if (toPosition == ScrollToPosition.Center)
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semanticLocation.Bounds = new Rect(0, viewportHeight / 2 - tHeight / 2, 0, 0);
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else
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semanticLocation.Bounds = new Rect(0, viewportHeight - tHeight, 0, 0);
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break;
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}
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}
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});
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// Waiting for loaded doesn't seem to be enough anymore; the ScrollViewer does not appear until after Loaded.
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// Even if the ScrollViewer is present, an invoke at low priority fails (E_FAIL) presumably because the items are
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// still loading. An invoke at idle sometimes work, but isn't reliable enough, so we'll just have to commit
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// treason and use a blanket catch for the E_FAIL and try again.
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try
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{
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List.MakeVisible(semanticLocation);
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}
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catch (Exception)
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{
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if (previouslyFailed)
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return;
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Task.Delay(1).ContinueWith(ct => { ScrollTo(group, item, toPosition, shouldAnimate, includeGroup, true); }, TaskScheduler.FromCurrentSynchronizationContext()).WatchForError();
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}
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}
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void OnElementScrollToRequested(object sender, ScrollToRequestedEventArgs e)
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{
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var scrollArgs = (ITemplatedItemsListScrollToRequestedEventArgs)e;
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ScrollTo(scrollArgs.Group, scrollArgs.Item, e.Position, e.ShouldAnimate);
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}
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T GetFirstDescendant<T>(DependencyObject element) where T : FrameworkElement
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{
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int count = VisualTreeHelper.GetChildrenCount(element);
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for (var i = 0; i < count; i++)
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{
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DependencyObject child = VisualTreeHelper.GetChild(element, i);
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T target = child as T ?? GetFirstDescendant<T>(child);
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if (target != null)
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return target;
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}
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return null;
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}
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ContentControl GetHeaderControl()
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{
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if (_headerControl == null)
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{
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ScrollViewer viewer = GetScrollViewer();
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if (viewer == null)
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return null;
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var presenter = GetFirstDescendant<ItemsPresenter>(viewer);
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if (presenter == null)
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return null;
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_headerControl = GetFirstDescendant<ContentControl>(presenter);
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}
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return _headerControl;
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}
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ScrollViewer GetScrollViewer()
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{
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if (_scrollViewer == null)
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{
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_scrollViewer = List.GetFirstDescendant<ScrollViewer>();
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}
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return _scrollViewer;
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}
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void ListOnTapped(object sender, TappedRoutedEventArgs args)
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{
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var orig = args.OriginalSource as DependencyObject;
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int index = -1;
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// Work our way up the tree until we find the actual list item
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// the user tapped on
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while (orig != null && orig != List)
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{
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var lv = orig as ListViewItem;
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if (lv != null)
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{
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index = TemplatedItemsView.TemplatedItems.GetGlobalIndexOfItem(lv.Content);
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break;
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}
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orig = VisualTreeHelper.GetParent(orig);
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}
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if (index > -1)
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{
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OnListItemClicked(index);
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}
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}
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void OnElementItemSelected(object sender, SelectedItemChangedEventArgs e)
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{
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if (Element == null)
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return;
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if (_deferSelection)
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{
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// If we get more than one of these, that's okay; we only want the latest one
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_deferredSelectedItemChangedEvent = new Tuple<object, SelectedItemChangedEventArgs>(sender, e);
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return;
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}
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if (e.SelectedItem == null)
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{
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List.SelectedIndex = -1;
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return;
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}
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var templatedItems = TemplatedItemsView.TemplatedItems;
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var index = 0;
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if (Element.IsGroupingEnabled)
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{
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int selectedItemIndex = templatedItems.GetGlobalIndexOfItem(e.SelectedItem);
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var leftOver = 0;
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int groupIndex = templatedItems.GetGroupIndexFromGlobal(selectedItemIndex, out leftOver);
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index = selectedItemIndex - (groupIndex + 1);
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}
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else
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{
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index = templatedItems.GetGlobalIndexOfItem(e.SelectedItem);
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}
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List.SelectedIndex = index;
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}
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void OnListItemClicked(int index)
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{
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Element.NotifyRowTapped(index);
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_itemWasClicked = true;
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}
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void OnListItemClicked(object sender, ItemClickEventArgs e)
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{
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if (e.ClickedItem != null && TemplatedItemsView?.TemplatedItems != null)
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{
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var templatedItems = TemplatedItemsView.TemplatedItems;
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var selectedItemIndex = templatedItems.GetGlobalIndexOfItem(e.ClickedItem);
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OnListItemClicked(selectedItemIndex);
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}
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}
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void OnControlSelectionChanged(object sender, WSelectionChangedEventArgs e)
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{
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if (Element.SelectedItem != List.SelectedItem)
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{
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if (_itemWasClicked)
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List.SelectedItem = Element.SelectedItem;
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else
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((IElementController)Element).SetValueFromRenderer(ListView.SelectedItemProperty, List.SelectedItem);
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}
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_itemWasClicked = false;
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}
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FrameworkElement FindElement(object cell)
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{
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foreach (CellControl selector in FindDescendants<CellControl>(List))
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{
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if (ReferenceEquals(cell, selector.DataContext))
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return selector;
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}
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return null;
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}
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bool _deferSelection = false;
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Tuple<object, SelectedItemChangedEventArgs> _deferredSelectedItemChangedEvent;
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protected override AutomationPeer OnCreateAutomationPeer()
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{
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if (List == null)
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return new FrameworkElementAutomationPeer(this);
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var automationPeer = new ListViewAutomationPeer(List);
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// skip this renderer from automationPeer tree to avoid infinity loop
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automationPeer.SetParent(new FrameworkElementAutomationPeer(Parent as FrameworkElement));
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return automationPeer;
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}
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}
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}
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