maui-linux/Handlers/CollectionViewHandler.cs

375 lines
13 KiB
C#

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using Microsoft.Maui.Handlers;
using Microsoft.Maui.Graphics;
using Microsoft.Maui.Controls;
using Microsoft.Maui.Platform;
using SkiaSharp;
namespace Microsoft.Maui.Platform.Linux.Handlers;
/// <summary>
/// Handler for CollectionView on Linux using Skia rendering.
/// Maps CollectionView to SkiaCollectionView platform view.
/// </summary>
public partial class CollectionViewHandler : ViewHandler<CollectionView, SkiaCollectionView>
{
private bool _isUpdatingSelection;
public static IPropertyMapper<CollectionView, CollectionViewHandler> Mapper =
new PropertyMapper<CollectionView, CollectionViewHandler>(ViewHandler.ViewMapper)
{
// ItemsView properties
[nameof(ItemsView.ItemsSource)] = MapItemsSource,
[nameof(ItemsView.ItemTemplate)] = MapItemTemplate,
[nameof(ItemsView.EmptyView)] = MapEmptyView,
[nameof(ItemsView.HorizontalScrollBarVisibility)] = MapHorizontalScrollBarVisibility,
[nameof(ItemsView.VerticalScrollBarVisibility)] = MapVerticalScrollBarVisibility,
// SelectableItemsView properties
[nameof(SelectableItemsView.SelectedItem)] = MapSelectedItem,
[nameof(SelectableItemsView.SelectedItems)] = MapSelectedItems,
[nameof(SelectableItemsView.SelectionMode)] = MapSelectionMode,
// StructuredItemsView properties
[nameof(StructuredItemsView.Header)] = MapHeader,
[nameof(StructuredItemsView.Footer)] = MapFooter,
[nameof(StructuredItemsView.ItemsLayout)] = MapItemsLayout,
[nameof(IView.Background)] = MapBackground,
[nameof(CollectionView.BackgroundColor)] = MapBackgroundColor,
};
public static CommandMapper<CollectionView, CollectionViewHandler> CommandMapper =
new(ViewHandler.ViewCommandMapper)
{
["ScrollTo"] = MapScrollTo,
};
public CollectionViewHandler() : base(Mapper, CommandMapper)
{
}
public CollectionViewHandler(IPropertyMapper? mapper, CommandMapper? commandMapper = null)
: base(mapper ?? Mapper, commandMapper ?? CommandMapper)
{
}
protected override SkiaCollectionView CreatePlatformView()
{
return new SkiaCollectionView();
}
protected override void ConnectHandler(SkiaCollectionView platformView)
{
base.ConnectHandler(platformView);
platformView.SelectionChanged += OnSelectionChanged;
platformView.Scrolled += OnScrolled;
platformView.ItemTapped += OnItemTapped;
}
protected override void DisconnectHandler(SkiaCollectionView platformView)
{
platformView.SelectionChanged -= OnSelectionChanged;
platformView.Scrolled -= OnScrolled;
platformView.ItemTapped -= OnItemTapped;
base.DisconnectHandler(platformView);
}
private void OnSelectionChanged(object? sender, CollectionSelectionChangedEventArgs e)
{
if (VirtualView is null || _isUpdatingSelection) return;
try
{
_isUpdatingSelection = true;
// Update virtual view selection
if (VirtualView.SelectionMode == SelectionMode.Single)
{
var newItem = e.CurrentSelection.FirstOrDefault();
if (!Equals(VirtualView.SelectedItem, newItem))
{
VirtualView.SelectedItem = newItem;
}
}
else if (VirtualView.SelectionMode == SelectionMode.Multiple)
{
// Clear and update selected items
VirtualView.SelectedItems.Clear();
foreach (var item in e.CurrentSelection)
{
VirtualView.SelectedItems.Add(item);
}
}
}
finally
{
_isUpdatingSelection = false;
}
}
private void OnScrolled(object? sender, ItemsScrolledEventArgs e)
{
VirtualView?.SendScrolled(new ItemsViewScrolledEventArgs
{
VerticalOffset = e.ScrollOffset,
VerticalDelta = 0,
HorizontalOffset = 0,
HorizontalDelta = 0
});
}
private void OnItemTapped(object? sender, ItemsViewItemTappedEventArgs e)
{
// Item tap is handled through selection
}
public static void MapItemsSource(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null) return;
handler.PlatformView.ItemsSource = collectionView.ItemsSource;
}
public static void MapItemTemplate(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null || handler.MauiContext is null) return;
var template = collectionView.ItemTemplate;
if (template != null)
{
// Set up a renderer that creates views from the DataTemplate
handler.PlatformView.ItemViewCreator = (item) =>
{
try
{
// Create view from template
var content = template.CreateContent();
if (content is View view)
{
// Set binding context FIRST so bindings evaluate
view.BindingContext = item;
// Force binding evaluation by accessing the visual tree
// This ensures child bindings are evaluated before handler creation
PropagateBindingContext(view, item);
// Create handler for the view
if (view.Handler == null && handler.MauiContext != null)
{
view.Handler = view.ToHandler(handler.MauiContext);
}
if (view.Handler?.PlatformView is SkiaView skiaView)
{
return skiaView;
}
}
else if (content is ViewCell cell)
{
cell.BindingContext = item;
var cellView = cell.View;
if (cellView != null)
{
if (cellView.Handler == null && handler.MauiContext != null)
{
cellView.Handler = cellView.ToHandler(handler.MauiContext);
}
if (cellView.Handler?.PlatformView is SkiaView skiaView)
{
return skiaView;
}
}
}
}
catch
{
// Ignore template creation errors
}
return null;
};
}
handler.PlatformView.Invalidate();
}
public static void MapEmptyView(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null) return;
handler.PlatformView.EmptyView = collectionView.EmptyView;
if (collectionView.EmptyView is string text)
{
handler.PlatformView.EmptyViewText = text;
}
}
public static void MapHorizontalScrollBarVisibility(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null) return;
handler.PlatformView.HorizontalScrollBarVisibility = (ScrollBarVisibility)collectionView.HorizontalScrollBarVisibility;
}
public static void MapVerticalScrollBarVisibility(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null) return;
handler.PlatformView.VerticalScrollBarVisibility = (ScrollBarVisibility)collectionView.VerticalScrollBarVisibility;
}
public static void MapSelectedItem(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null || handler._isUpdatingSelection) return;
try
{
handler._isUpdatingSelection = true;
if (!Equals(handler.PlatformView.SelectedItem, collectionView.SelectedItem))
{
handler.PlatformView.SelectedItem = collectionView.SelectedItem;
}
}
finally
{
handler._isUpdatingSelection = false;
}
}
public static void MapSelectedItems(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null || handler._isUpdatingSelection) return;
try
{
handler._isUpdatingSelection = true;
// Sync selected items
var selectedItems = collectionView.SelectedItems;
if (selectedItems != null && selectedItems.Count > 0)
{
handler.PlatformView.SelectedItem = selectedItems.First();
}
}
finally
{
handler._isUpdatingSelection = false;
}
}
public static void MapSelectionMode(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null) return;
handler.PlatformView.SelectionMode = collectionView.SelectionMode switch
{
SelectionMode.None => SkiaSelectionMode.None,
SelectionMode.Single => SkiaSelectionMode.Single,
SelectionMode.Multiple => SkiaSelectionMode.Multiple,
_ => SkiaSelectionMode.None
};
}
public static void MapHeader(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null) return;
handler.PlatformView.Header = collectionView.Header;
}
public static void MapFooter(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null) return;
handler.PlatformView.Footer = collectionView.Footer;
}
public static void MapItemsLayout(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null) return;
var layout = collectionView.ItemsLayout;
if (layout is LinearItemsLayout linearLayout)
{
handler.PlatformView.Orientation = linearLayout.Orientation == Controls.ItemsLayoutOrientation.Vertical
? Platform.ItemsLayoutOrientation.Vertical
: Platform.ItemsLayoutOrientation.Horizontal;
handler.PlatformView.SpanCount = 1;
handler.PlatformView.ItemSpacing = (float)linearLayout.ItemSpacing;
}
else if (layout is GridItemsLayout gridLayout)
{
handler.PlatformView.Orientation = gridLayout.Orientation == Controls.ItemsLayoutOrientation.Vertical
? Platform.ItemsLayoutOrientation.Vertical
: Platform.ItemsLayoutOrientation.Horizontal;
handler.PlatformView.SpanCount = gridLayout.Span;
handler.PlatformView.ItemSpacing = (float)gridLayout.VerticalItemSpacing;
}
}
public static void MapBackground(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null) return;
// Don't override if BackgroundColor is explicitly set
if (collectionView.BackgroundColor is not null)
return;
if (collectionView.Background is SolidColorBrush solidBrush)
{
handler.PlatformView.BackgroundColor = solidBrush.Color.ToSKColor();
}
}
public static void MapBackgroundColor(CollectionViewHandler handler, CollectionView collectionView)
{
if (handler.PlatformView is null) return;
if (collectionView.BackgroundColor is not null)
{
handler.PlatformView.BackgroundColor = collectionView.BackgroundColor.ToSKColor();
}
}
public static void MapScrollTo(CollectionViewHandler handler, CollectionView collectionView, object? args)
{
if (handler.PlatformView is null || args is not ScrollToRequestEventArgs scrollArgs)
return;
if (scrollArgs.Mode == ScrollToMode.Position)
{
handler.PlatformView.ScrollToIndex(scrollArgs.Index, scrollArgs.IsAnimated);
}
else if (scrollArgs.Item != null)
{
handler.PlatformView.ScrollToItem(scrollArgs.Item, scrollArgs.IsAnimated);
}
}
/// <summary>
/// Recursively propagates binding context to all child views to force binding evaluation.
/// </summary>
private static void PropagateBindingContext(View view, object? bindingContext)
{
view.BindingContext = bindingContext;
// Propagate to children
if (view is Layout layout)
{
foreach (var child in layout.Children)
{
if (child is View childView)
{
PropagateBindingContext(childView, bindingContext);
}
}
}
else if (view is ContentView contentView && contentView.Content != null)
{
PropagateBindingContext(contentView.Content, bindingContext);
}
else if (view is Border border && border.Content is View borderContent)
{
PropagateBindingContext(borderContent, bindingContext);
}
}
}