internal void UpdateSubview(object view, DataTemplate viewTemplate, nint viewTag, ref UIView uiView, ref VisualElement formsElement)
{
uiView?.RemoveFromSuperview();
if (formsElement != null)
{
ItemsView.RemoveLogicalChild(formsElement);
formsElement.MeasureInvalidated -= OnFormsElementMeasureInvalidated;
}
UpdateView(view, viewTemplate, ref uiView, ref formsElement);
if (uiView != null)
{
uiView.Tag = viewTag;
CollectionView.AddSubview(uiView);
}
if (formsElement != null)
{
ItemsView.AddLogicalChild(formsElement);
}
if (formsElement != null)
{
RemeasureLayout(formsElement);
formsElement.MeasureInvalidated += OnFormsElementMeasureInvalidated;
}
else if (uiView != null)
{
uiView.SizeToFit();
}
}
protected void UpdateSubview(object view, DataTemplate viewTemplate, ref UIView uiView, ref VisualElement formsElement)
{
if (uiView != null)
{
CollectionView.Subviews.Remove(uiView);
}
if (formsElement != null)
{
ItemsView.RemoveLogicalChild(formsElement);
formsElement.MeasureInvalidated -= OnFormsElementMeasureInvalidated;
}
UpdateView(view, viewTemplate, ref uiView, ref formsElement);
if (uiView != null)
{
CollectionView.AddSubview(uiView);
}
if (formsElement != null)
{
ItemsView.AddLogicalChild(formsElement);
}
if (formsElement != null)
{
RemeasureLayout(formsElement);
formsElement.MeasureInvalidated += OnFormsElementMeasureInvalidated;
}
else if (uiView != null)
{
uiView.SizeToFit();
}
}
public void Bind(object itemBindingContext, ItemsView itemsView,
Action <Size> reportMeasure = null, Size?size = null)
{
var template = _template.SelectDataTemplate(itemBindingContext, itemsView);
var templateChanging = template != _selectedTemplate;
if (templateChanging)
{
// Clean up any content we're still holding on to
_itemContentView.Recycle();
// Create the new content
View = (View)template.CreateContent();
// Set the binding context _before_ we create the renderer; that way, the bound data will be
// available during OnElementChanged
View.BindingContext = itemBindingContext;
// Actually create the native renderer
_itemContentView.RealizeContent(View);
_selectedTemplate = template;
}
_itemContentView.HandleItemSizingStrategy(reportMeasure, size);
if (!templateChanging)
{
// Same template, new data
View.BindingContext = itemBindingContext;
}
itemsView.AddLogicalChild(View);
}
public void Bind(DataTemplate template, object bindingContext, ItemsView itemsView)
{
var oldElement = VisualElementRenderer?.Element;
// Run this through the extension method in case it's really a DataTemplateSelector
var itemTemplate = template.SelectDataTemplate(bindingContext, itemsView);
if (itemTemplate != _currentTemplate)
{
// Remove the old view, if it exists
if (oldElement != null)
{
oldElement.MeasureInvalidated -= MeasureInvalidated;
itemsView.RemoveLogicalChild(oldElement);
ClearSubviews();
_size = Size.Zero;
}
// Create the content and renderer for the view
var view = itemTemplate.CreateContent() as View;
// Prevents the use of default color when there are VisualStateManager with Selected state setting the background color
// First we check whether the cell has the default selected background color; if it does, then we should check
// to see if the cell content is the VSM to set a selected color
if (SelectedBackgroundView.BackgroundColor == ColorExtensions.Gray && IsUsingVSMForSelectionColor(view))
{
SelectedBackgroundView = new UIView
{
BackgroundColor = UIColor.Clear
};
}
// Set the binding context _before_ we create the renderer; that way, it's available during OnElementChanged
view.BindingContext = bindingContext;
var renderer = TemplateHelpers.CreateRenderer(view);
SetRenderer(renderer);
// And make the new Element a "child" of the ItemsView
// We deliberately do this _after_ setting the binding context for the new element;
// if we do it before, the element briefly inherits the ItemsView's bindingcontext and we
// emit a bunch of needless binding errors
itemsView.AddLogicalChild(view);
}
else
{
// Same template, different data
var currentElement = VisualElementRenderer?.Element;
if (currentElement != null)
{
currentElement.BindingContext = bindingContext;
}
}
_currentTemplate = itemTemplate;
}
void ApplyTemplateAndDataContext(TemplatedCell cell, NSIndexPath indexPath)
{
// We need to create a renderer, which means we need a template
var view = _itemsView.ItemTemplate.CreateContent() as View;
_itemsView.AddLogicalChild(view);
var renderer = CreateRenderer(view);
BindableObject.SetInheritedBindingContext(view, _itemsSource[indexPath.Row]);
cell.SetRenderer(renderer);
}
public override void SetBinding(EvasObject native, int index)
{
if (_nativeFormsTable.TryGetValue(native, out View view))
{
ResetBindedView(view);
view.BindingContext = this[index];
_dataBindedViewTable[this[index]] = view;
view.MeasureInvalidated += OnItemMeasureInvalidated;
_itemsView.AddLogicalChild(view);
}
}
public void Bind(object itemBindingContext, ItemsView itemsView)
{
var template = _template.SelectDataTemplate(itemBindingContext, itemsView);
View = (View)template.CreateContent();
_itemContentView.RealizeContent(View);
// Set the binding context before we add it as a child of the ItemsView; otherwise, it will
// inherit the ItemsView's binding context
View.BindingContext = itemBindingContext;
itemsView.AddLogicalChild(View);
}
public void Bind(DataTemplate template, object bindingContext, ItemsView itemsView)
{
var oldElement = VisualElementRenderer?.Element;
// Run this through the extension method in case it's really a DataTemplateSelector
var itemTemplate = template.SelectDataTemplate(bindingContext, itemsView);
if (itemTemplate != _currentTemplate)
{
// Remove the old view, if it exists
if (oldElement != null)
{
oldElement.MeasureInvalidated -= MeasureInvalidated;
itemsView.RemoveLogicalChild(oldElement);
ClearSubviews();
_size = Size.Zero;
}
// Create the content and renderer for the view
var view = itemTemplate.CreateContent() as View;
// Set the binding context _before_ we create the renderer; that way, it's available during OnElementChanged
view.BindingContext = bindingContext;
var renderer = TemplateHelpers.CreateRenderer(view);
SetRenderer(renderer);
// And make the new Element a "child" of the ItemsView
// We deliberately do this _after_ setting the binding context for the new element;
// if we do it before, the element briefly inherits the ItemsView's bindingcontext and we
// emit a bunch of needless binding errors
itemsView.AddLogicalChild(view);
}
else
{
// Same template, different data
var currentElement = VisualElementRenderer?.Element;
if (currentElement != null)
{
currentElement.BindingContext = bindingContext;
}
}
_currentTemplate = itemTemplate;
}
protected virtual void UpdateEmptyViewVisibility()
{
bool isEmpty = (CollectionViewSource?.View?.Count ?? 0) == 0;
if (isEmpty)
{
if (_formsEmptyView != null)
{
if (_emptyViewDisplayed)
{
ItemsView.RemoveLogicalChild(_formsEmptyView);
}
if (ItemsView.EmptyViewTemplate == null)
{
ItemsView.AddLogicalChild(_formsEmptyView);
}
}
if (_emptyView != null && ListViewBase is IEmptyView emptyView)
{
emptyView.EmptyViewVisibility = WVisibility.Visible;
if (ActualWidth >= 0 && ActualHeight >= 0)
{
_formsEmptyView?.Layout(new Rect(0, 0, ActualWidth, ActualHeight));
}
}
_emptyViewDisplayed = true;
}
else
{
if (_emptyViewDisplayed)
{
if (_emptyView != null && ListViewBase is IEmptyView emptyView)
{
emptyView.EmptyViewVisibility = WVisibility.Collapsed;
}
ItemsView.RemoveLogicalChild(_formsEmptyView);
}
_emptyViewDisplayed = false;
}
}
void UpdateEmptyViewVisibility(bool isEmpty)
{
if (isEmpty && _emptyUIView != null)
{
var emptyView = CollectionView.ViewWithTag(EmptyTag);
if (emptyView != null)
{
emptyView.RemoveFromSuperview();
ItemsView.RemoveLogicalChild(_emptyViewFormsElement);
}
_emptyUIView.Tag = EmptyTag;
CollectionView.AddSubview(_emptyUIView);
LayoutEmptyView();
if (_emptyViewFormsElement != null)
{
if (ItemsView.EmptyViewTemplate == null)
{
ItemsView.AddLogicalChild(_emptyViewFormsElement);
}
// Now that the native empty view's frame is sized to the UICollectionView, we need to handle
// the Forms layout for its content
_emptyViewFormsElement.Layout(_emptyUIView.Frame.ToRectangle());
}
_emptyViewDisplayed = true;
}
else
{
// Is the empty view currently in the background? Swap back to the default.
if (_emptyViewDisplayed)
{
_emptyUIView.RemoveFromSuperview();
_emptyUIView.Dispose();
_emptyUIView = null;
ItemsView.RemoveLogicalChild(_emptyViewFormsElement);
}
_emptyViewDisplayed = false;
}
}
void ShowEmptyView()
{
if (_emptyViewDisplayed || _emptyUIView == null)
{
return;
}
_emptyUIView.Tag = EmptyTag;
CollectionView.AddSubview(_emptyUIView);
if (((IElementController)ItemsView).LogicalChildren.IndexOf(_emptyViewFormsElement) == -1)
{
ItemsView.AddLogicalChild(_emptyViewFormsElement);
}
LayoutEmptyView();
AlignEmptyView();
_emptyViewDisplayed = true;
}
void ApplyTemplateAndDataContext(TemplatedCell cell, NSIndexPath indexPath)
{
var template = _itemsView.ItemTemplate;
var item = _itemsSource[indexPath.Row];
// Run this through the extension method in case it's really a DataTemplateSelector
template = template.SelectDataTemplate(item, _itemsView);
// Create the content and renderer for the view and
var view = template.CreateContent() as View;
var renderer = CreateRenderer(view);
cell.SetRenderer(renderer);
// Bind the view to the data item
view.BindingContext = _itemsSource[indexPath.Row];
// And make sure it's a "child" of the ItemsView
_itemsView.AddLogicalChild(view);
}
void ShowEmptyView()
{
if (_emptyViewDisplayed || _emptyUIView == null)
{
return;
}
_emptyUIView.Tag = EmptyTag;
CollectionView.AddSubview(_emptyUIView);
if (!ItemsView.LogicalChildren.Contains(_emptyViewFormsElement))
{
ItemsView.AddLogicalChild(_emptyViewFormsElement);
}
LayoutEmptyView();
AlignEmptyView();
_emptyViewDisplayed = true;
}
protected RecyclerView.ViewHolder CreateHeaderFooterViewHolder(object content, DataTemplate template, Context context)
{
if (template != null)
{
var footerContentView = new ItemContentView(context);
return(new TemplatedItemViewHolder(footerContentView, template, isSelectionEnabled: false));
}
if (content is View formsView)
{
var viewHolder = SimpleViewHolder.FromFormsView(formsView, context);
// Propagate the binding context, visual, etc. from the ItemsView to the header/footer
ItemsView.AddLogicalChild(viewHolder.View);
return(viewHolder);
}
// No template, Footer is not a Forms View, so just display Footer.ToString
return(SimpleViewHolder.FromText(content?.ToString(), context, fill: false));
}
public void Bind(object itemBindingContext, ItemsView itemsView,
Action <Size> reportMeasure = null, Size?size = null)
{
var template = _template.SelectDataTemplate(itemBindingContext, itemsView);
if (template != _selectedTemplate)
{
_itemContentView.Recycle();
View = (View)template.CreateContent();
_itemContentView.RealizeContent(View);
_selectedTemplate = template;
}
_itemContentView.HandleItemSizingStrategy(reportMeasure, size);
// Set the binding context before we add it as a child of the ItemsView; otherwise, it will
// inherit the ItemsView's binding context
View.BindingContext = itemBindingContext;
itemsView.AddLogicalChild(View);
}
void UpdateEmptyViewVisibility(bool isEmpty)
{
if (isEmpty && _emptyUIView != null)
{
if (!_currentBackgroundIsEmptyView)
{
// Cache any existing background view so we can restore it later
_backgroundUIView = CollectionView.BackgroundView;
}
// Replace any current background with the EmptyView. This will also set the native empty view's frame
// to match the UICollectionView's frame
CollectionView.BackgroundView = _emptyUIView;
if (_emptyViewFormsElement != null)
{
if (ItemsView.EmptyViewTemplate == null)
{
ItemsView.AddLogicalChild(_emptyViewFormsElement);
}
// Now that the native empty view's frame is sized to the UICollectionView, we need to handle
// the Forms layout for its content
_emptyViewFormsElement.Layout(_emptyUIView.Frame.ToRectangle());
}
_currentBackgroundIsEmptyView = true;
}
else
{
// Is the empty view currently in the background? Swap back to the default.
if (_currentBackgroundIsEmptyView)
{
CollectionView.BackgroundView = _backgroundUIView;
ItemsView.RemoveLogicalChild(_emptyViewFormsElement);
}
_currentBackgroundIsEmptyView = false;
}
}
public void Bind(DataTemplate template, object bindingContext, ItemsView itemsView)
{
var oldElement = VisualElementRenderer?.Element;
if (template != _currentTemplate)
{
// Remove the old view, if it exists
if (oldElement != null)
{
oldElement.MeasureInvalidated -= MeasureInvalidated;
itemsView.RemoveLogicalChild(oldElement);
ClearSubviews();
_size = Size.Zero;
}
// Create the content and renderer for the view
var view = template.CreateContent() as View;
var renderer = TemplateHelpers.CreateRenderer(view);
SetRenderer(renderer);
}
var currentElement = VisualElementRenderer?.Element;
// Bind the view to the data item
if (currentElement != null)
{
currentElement.BindingContext = bindingContext;
}
if (template != _currentTemplate)
{
// And make the Element a "child" of the ItemsView
// We deliberately do this _after_ setting the binding context for the new element;
// if we do it before, the element briefly inherits the ItemsView's bindingcontext and we
// emit a bunch of needless binding errors
itemsView.AddLogicalChild(currentElement);
}
_currentTemplate = template;
}
public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
{
var context = parent.Context;
// Does the ItemsView have a DataTemplate?
var template = ItemsView.ItemTemplate;
if (template == null)
{
// No template, just use the ToString view
var view = new TextView(context);
return(new TextViewHolder(view));
}
// Realize the content, create a renderer out of it, and use that
var templateElement = (View)template.CreateContent();
ItemsView.AddLogicalChild(templateElement);
var itemContentControl = _createView(CreateRenderer(templateElement, context), context);
return(new TemplatedItemViewHolder(itemContentControl, templateElement));
}
internal void UpdateSubview(object view, DataTemplate viewTemplate, ref UIView uiView, ref VisualElement formsElement)
{
if (uiView != null)
{
CollectionView.Subviews.Remove(uiView);
}
if (formsElement != null)
{
ItemsView.RemoveLogicalChild(formsElement);
formsElement.MeasureInvalidated -= OnFormsElementMeasureInvalidated;
}
UpdateView(view, viewTemplate, ref uiView, ref formsElement);
if (uiView != null)
{
CollectionView.AddSubview(uiView);
}
if (formsElement != null)
{
ItemsView.AddLogicalChild(formsElement);
}
if (formsElement != null)
{
var request = formsElement.Measure(CollectionView.Frame.Width, double.PositiveInfinity, MeasureFlags.IncludeMargins);
Xamarin.Forms.Layout.LayoutChildIntoBoundingRegion(formsElement, new Rectangle(0, -request.Request.Height, CollectionView.Frame.Width, request.Request.Height));
formsElement.MeasureInvalidated += OnFormsElementMeasureInvalidated;
}
else if (uiView != null)
{
uiView.SizeToFit();
}
}
