internal void UpdateSnapBehavior(IItemsLayout iitemsLayout)
{
if (iitemsLayout is not ItemsLayout itemsLayout)
{
return;
}
var snapPointsType = itemsLayout.SnapPointsType;
// Clear our the existing snap helper (if any)
DetachSnapHelper();
if (snapPointsType == SnapPointsType.None)
{
return;
}
var alignment = itemsLayout.SnapPointsAlignment;
// Create a new snap helper
_snapHelper = CreateSnapHelper(snapPointsType, alignment);
// And attach it to this RecyclerView
_snapHelper.AttachToRecyclerView(_recyclerView);
}
void SetUpNewElement(ItemsView newElement)
{
if (newElement == null)
{
return;
}
newElement.PropertyChanged += OnElementPropertyChanged;
// TODO hartez 2018/06/06 20:49:14 Review whether we can just do this in the constructor
if (Tracker == null)
{
Tracker = new VisualElementTracker(this);
}
this.EnsureId();
UpdateItemsSource();
_layout = newElement.ItemsLayout;
SetLayoutManager(SelectLayoutManager(_layout));
UpdateSnapBehavior();
// Keep track of the ItemsLayout's property changes
_layout.PropertyChanged += LayoutOnPropertyChanged;
// TODO hartez 2018/09/17 13:16:12 This propertychanged handler needs to be torn down in Dispose and TearDownElement
// Listen for ScrollTo requests
newElement.ScrollToRequested += ScrollToRequested;
}
public static T ItemsLayout <T>(this T structuredElement, IItemsLayout itemsLayout)
where T : StructuredItemsView
{
structuredElement.ItemsLayout = itemsLayout;
return(structuredElement);
}
public CarouselSpacingItemDecoration(IItemsLayout itemsLayout)
{
var layout = itemsLayout ?? throw new ArgumentNullException(nameof(itemsLayout));
switch (layout)
{
case GridItemsLayout gridItemsLayout:
_orientation = gridItemsLayout.Orientation;
_horizontalSpacing = gridItemsLayout.HorizontalItemSpacing;
_verticalSpacing = gridItemsLayout.VerticalItemSpacing;
break;
case ListItemsLayout listItemsLayout:
_orientation = listItemsLayout.Orientation;
if (_orientation == ItemsLayoutOrientation.Horizontal)
{
_horizontalSpacing = listItemsLayout.ItemSpacing;
}
else
{
_verticalSpacing = listItemsLayout.ItemSpacing;
}
break;
}
}
public TemplateCodeCollectionViewGallery(IItemsLayout itemsLayout)
{
var layout = new Grid
{
RowDefinitions = new RowDefinitionCollection
{
new RowDefinition {
Height = GridLength.Auto
},
new RowDefinition {
Height = GridLength.Star
}
}
};
var itemTemplate = ExampleTemplates.PhotoTemplate();
var collectionView = new CollectionView
{
ItemsLayout = itemsLayout,
ItemTemplate = itemTemplate
};
var generator = new ItemsSourceGenerator(collectionView, initialItems: 20);
layout.Children.Add(generator);
layout.Children.Add(collectionView);
Grid.SetRow(collectionView, 1);
Content = layout;
generator.GenerateItems();
}
void SetUpNewElement(ItemsView newElement)
{
if (newElement == null)
{
return;
}
if (ListViewBase == null)
{
ListViewBase = SelectLayout(newElement.ItemsLayout);
_layout = newElement.ItemsLayout;
_layout.PropertyChanged += LayoutOnPropertyChanged;
SetNativeControl(ListViewBase);
}
UpdateItemTemplate();
UpdateItemsSource();
UpdateVerticalScrollBarVisibility();
UpdateHorizontalScrollBarVisibility();
// Listen for ScrollTo requests
newElement.ScrollToRequested += ScrollToRequested;
}
protected virtual void SetUpNewElement(ItemsView newElement)
{
if (newElement == null)
{
return;
}
if (ListViewBase == null)
{
ListViewBase = SelectLayout(newElement.ItemsLayout);
ListViewBase.IsSynchronizedWithCurrentItem = false;
_layout = newElement.ItemsLayout;
_layout.PropertyChanged += LayoutPropertyChanged;
SetNativeControl(ListViewBase);
}
UpdateItemTemplate();
UpdateItemsSource();
UpdateHeader();
UpdateFooter();
UpdateVerticalScrollBarVisibility();
UpdateHorizontalScrollBarVisibility();
// Listen for ScrollTo requests
newElement.ScrollToRequested += ScrollToRequested;
}
public SpacingModifier(IItemsLayout itemsLayout, string buttonText)
{
ItemsLayout = itemsLayout;
var layout = new StackLayout
{
Orientation = StackOrientation.Horizontal,
HorizontalOptions = LayoutOptions.Fill
};
var button = new Button {
Text = buttonText, AutomationId = $"btn{buttonText}"
};
var label = new Label {
Text = LabelText, VerticalTextAlignment = TextAlignment.Center
};
Entry = new Entry {
Text = InitialEntryText, WidthRequest = 100, AutomationId = $"entry{buttonText}"
};
layout.Children.Add(label);
layout.Children.Add(Entry);
layout.Children.Add(button);
button.Clicked += ButtonOnClicked;
Content = layout;
}
public TextCodeCollectionViewGallery(IItemsLayout itemsLayout)
{
var layout = new Grid
{
RowDefinitions = new RowDefinitionCollection
{
new RowDefinition {
Height = GridLength.Auto
},
new RowDefinition {
Height = GridLength.Star
}
}
};
var collectionView = new CollectionView
{
ItemsLayout = itemsLayout,
SelectionMode = SelectionMode.Single,
AutomationId = "collectionview"
};
var generator = new ItemsSourceGenerator(collectionView);
layout.Children.Add(generator);
layout.Children.Add(collectionView);
Grid.SetRow(collectionView, 1);
Content = layout;
generator.GenerateItems();
}
public SpacingItemDecoration(IItemsLayout itemsLayout)
{
if (itemsLayout == null)
{
throw new ArgumentNullException(nameof(itemsLayout));
}
switch (itemsLayout)
{
case GridItemsLayout gridItemsLayout:
_orientation = gridItemsLayout.Orientation;
_horizontalSpacing = gridItemsLayout.HorizontalItemSpacing;
_verticalSpacing = gridItemsLayout.VerticalItemSpacing;
_span = gridItemsLayout.Span;
break;
case ListItemsLayout listItemsLayout:
_orientation = listItemsLayout.Orientation;
if (_orientation == ItemsLayoutOrientation.Horizontal)
{
_horizontalSpacing = listItemsLayout.ItemSpacing;
}
else
{
_verticalSpacing = listItemsLayout.ItemSpacing;
}
break;
}
}
public SpacingGallery(IItemsLayout itemsLayout)
{
var layout = new Grid
{
RowDefinitions = new RowDefinitionCollection
{
new RowDefinition {
Height = GridLength.Auto
},
new RowDefinition {
Height = GridLength.Auto
},
new RowDefinition {
Height = GridLength.Auto
},
new RowDefinition {
Height = GridLength.Star
}
}
};
var instructions = new Label
{
Text = "Use the control below to update the spacing between items."
};
if (itemsLayout is GridItemsLayout)
{
instructions.Text += " Format is '[vertical], [horizontal]'";
}
var itemTemplate = ExampleTemplates.SpacingTemplate();
var collectionView = new CollectionView
{
ItemsLayout = itemsLayout,
ItemTemplate = itemTemplate,
AutomationId = "collectionview",
Margin = 10
};
var generator = new ItemsSourceGenerator(collectionView, initialItems: 20);
var spacingModifier = new SpacingModifier(collectionView.ItemsLayout, "Update_Spacing");
layout.Children.Add(generator);
layout.Children.Add(instructions);
layout.Children.Add(spacingModifier);
layout.Children.Add(collectionView);
Grid.SetRow(instructions, 1);
Grid.SetRow(spacingModifier, 2);
Grid.SetRow(collectionView, 3);
Content = layout;
generator.GenerateItems();
}
protected override ItemsViewLayout SelectLayout(IItemsLayout layoutSpecification, ItemSizingStrategy itemSizingStrategy)
{
if (layoutSpecification is ListItemsLayout listItemsLayout)
{
return(new CarouselViewLayout(listItemsLayout, itemSizingStrategy, CarouselView));
}
// Fall back to horizontal carousel
return(new CarouselViewLayout(new ListItemsLayout(ItemsLayoutOrientation.Horizontal), itemSizingStrategy, CarouselView));
}
public ScrollToCodeGallery(IItemsLayout itemsLayout, ScrollToMode mode = ScrollToMode.Position, Func <DataTemplate> dataTemplate = null, Func <CollectionView> createCollectionView = null)
{
createCollectionView = createCollectionView ?? (() => new CollectionView());
Title = $"ScrollTo (Code, {itemsLayout})";
var layout = new Grid
{
RowDefinitions = new RowDefinitionCollection
{
new RowDefinition {
Height = GridLength.Auto
},
new RowDefinition {
Height = GridLength.Auto
},
new RowDefinition {
Height = GridLength.Star
}
}
};
var itemTemplate = dataTemplate == null?ExampleTemplates.ScrollToIndexTemplate() : dataTemplate();
var collectionView = createCollectionView();
collectionView.ItemsLayout = itemsLayout;
collectionView.ItemTemplate = itemTemplate;
var generator = new ItemsSourceGenerator(collectionView, initialItems: 50);
layout.Children.Add(generator);
if (mode == ScrollToMode.Position)
{
var scrollToControl = new ScrollToIndexControl(collectionView);
layout.Children.Add(scrollToControl);
Grid.SetRow(scrollToControl, 1);
}
else
{
var scrollToControl = new ScrollToItemControl(collectionView);
layout.Children.Add(scrollToControl);
Grid.SetRow(scrollToControl, 1);
}
layout.Children.Add(collectionView);
Grid.SetRow(collectionView, 2);
Content = layout;
generator.GenerateItems();
}
void SetupColletionViewLayout()
{
disableUpdates = true;
var resetCV = cv;
if (linearLayout == null && cv.ItemsLayout is LinearItemsLayout linear)
{
linearLayout = cv.ItemsLayout;
linear.SnapPointsType = SnapPointsType.None;
linear.SnapPointsAlignment = SnapPointsAlignment.Start;
}
if (gridLayout == null && cv.ItemsLayout is GridItemsLayout)
{
gridLayout = cv.ItemsLayout;
}
if (FormsWindow.IsLandscape)
{
if (cv.ItemsLayout != linearLayout)
{
resetCV.ItemsSource = null;
resetCV.ItemsLayout = linearLayout;
Content = null;
}
}
else
{
if (cv.ItemsLayout != gridLayout)
{
resetCV.ItemsSource = null;
resetCV.ItemsLayout = gridLayout;
Content = null;
}
}
if (Content == null)
{
Device.BeginInvokeOnMainThread(() =>
{
Content = resetCV;
resetCV.ItemsSource =
Enumerable.Range(0, 1000)
.Select(i => $"Page {i}")
.ToList();
disableUpdates = false;
});
}
else
{
disableUpdates = false;
}
}
protected override void OnElementChanged(ElementChangedEventArgs <TItemsView> e)
{
if (Control == null)
{
SetNativeControl(CreateNativeControl(Forms.NativeParent));
}
if (e.NewElement != null)
{
e.NewElement.ScrollToRequested += OnScrollToRequest;
}
base.OnElementChanged(e);
ItemsLayout = GetItemsLayout();
UpdateAdaptor(false);
}
protected void UpdateItemsLayout()
{
if (ItemsLayout != null)
{
ItemsLayout.PropertyChanged -= OnLayoutPropertyChanged;
}
ItemsLayout = GetItemsLayout();
if (ItemsLayout != null)
{
Control.LayoutManager = ItemsLayout.ToLayoutManager((Element as CollectionView)?.ItemSizingStrategy ?? ItemSizingStrategy.MeasureFirstItem);
Control.SnapPointsType = ((ItemsLayout)ItemsLayout)?.SnapPointsType ?? SnapPointsType.None;
ItemsLayout.PropertyChanged += OnLayoutPropertyChanged;
}
}
protected virtual ItemsViewLayout SelectLayout(IItemsLayout layoutSpecification)
{
if (layoutSpecification is GridItemsLayout gridItemsLayout)
{
return(new GridViewLayout(gridItemsLayout));
}
if (layoutSpecification is ListItemsLayout listItemsLayout)
{
return(new ListViewLayout(listItemsLayout));
}
// Fall back to vertical list
return(new ListViewLayout(new ListItemsLayout(ItemsLayoutOrientation.Vertical)));
}
protected virtual ListViewBase SelectLayout(IItemsLayout layoutSpecification)
{
switch (layoutSpecification)
{
case GridItemsLayout gridItemsLayout:
return(CreateGridView(gridItemsLayout));
case ListItemsLayout listItemsLayout
when listItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal:
return(CreateHorizontalListView());
}
// Default to a plain old vertical ListView
return(new Windows.UI.Xaml.Controls.ListView());
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
if (_itemDecoration != null)
{
_itemDecoration.Dispose();
_itemDecoration = null;
}
_layout = null;
}
base.Dispose(disposing);
}
public static ICollectionViewLayoutManager ToLayoutManager(this IItemsLayout layout)
{
switch (layout)
{
case ListItemsLayout listItemsLayout:
return(new LinearLayoutManager(listItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal));
case GridItemsLayout gridItemsLayout:
return(new GridLayoutManager(gridItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal, gridItemsLayout.Span));
default:
break;
}
return(new LinearLayoutManager(false));
}
public static ICollectionViewLayoutManager ToLayoutManager(this IItemsLayout layout, ItemSizingStrategy sizing = ItemSizingStrategy.MeasureFirstItem)
{
switch (layout)
{
case LinearItemsLayout listItemsLayout:
return(new LinearLayoutManager(listItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal, sizing));
case GridItemsLayout gridItemsLayout:
return(new GridLayoutManager(gridItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal, gridItemsLayout.Span, sizing));
default:
break;
}
return(new LinearLayoutManager(false));
}
protected override LayoutManager SelectLayoutManager(IItemsLayout layoutSpecification)
{
if (layoutSpecification is StaggeredGridItemsLayout staggeredGridLayout)
{
var manager = new StaggeredGridLayoutManager(staggeredGridLayout.Span,
staggeredGridLayout.Orientation == ItemsLayoutOrientation.Horizontal
? LinearLayoutManager.Horizontal
: LinearLayoutManager.Vertical);
manager.GapStrategy = StaggeredGridLayoutManager.GapHandlingNone;
return(manager);
}
return(base.SelectLayoutManager(layoutSpecification));
}
public SpacingItemDecoration(Context context, IItemsLayout itemsLayout)
{
// The original "SpacingItemDecoration" applied spacing based on an item's current span index.
// It did not apply any spacing to items currently at span index 0 which can create an issue for us with grid layouts.
// If one of those items at span index 0 were to move to another column, it would result in misaligned items.
// It's better to just apply equal spacing to all items so we can avoid that issue (even the ones at span index 0).
// The reason they didn't do this originally, I suspect, is that they didn't want spacing around the edge of the RecyclerView.
// That however can be corrected by adjusting the padding on the RecyclerView which we are now doing.
if (itemsLayout == null)
{
throw new ArgumentNullException(nameof(itemsLayout));
}
double horizontalOffset;
double verticalOffset;
switch (itemsLayout)
{
case GridItemsLayout gridItemsLayout:
horizontalOffset = gridItemsLayout.HorizontalItemSpacing / 2.0;
verticalOffset = gridItemsLayout.VerticalItemSpacing / 2.0;
break;
case LinearItemsLayout listItemsLayout:
if (listItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal)
{
horizontalOffset = listItemsLayout.ItemSpacing / 2.0;
verticalOffset = 0;
}
else
{
horizontalOffset = 0;
verticalOffset = listItemsLayout.ItemSpacing / 2.0;
}
break;
default:
horizontalOffset = 0;
verticalOffset = 0;
break;
}
HorizontalOffset = (int)context.ToPixels(horizontalOffset);
VerticalOffset = (int)context.ToPixels(verticalOffset);
}
protected override void SetUpNewElement(ItemsView newElement)
{
base.SetUpNewElement(newElement);
if (newElement == null)
{
Carousel = null;
return;
}
Carousel = newElement as CarouselView;
_layout = ItemsView.ItemsLayout;
UpdateIsSwipeEnabled();
UpdateInitialPosition();
UpdateItemSpacing();
}
void TearDownOldElement(ItemsView oldElement)
{
if (oldElement == null)
{
return;
}
if (_layout != null)
{
// Stop tracking the old layout
_layout.PropertyChanged -= LayoutOnPropertyChanged;
_layout = null;
}
// Stop listening for ScrollTo requests
oldElement.ScrollToRequested -= ScrollToRequested;
}
public DynamicItemSizeGallery(IItemsLayout itemsLayout)
{
var layout = new Grid
{
RowDefinitions = new RowDefinitionCollection
{
new RowDefinition {
Height = GridLength.Auto
},
new RowDefinition {
Height = GridLength.Auto
},
new RowDefinition {
Height = GridLength.Star
}
}
};
var instructions = new Label
{
Text = "Tap the buttons in each item to increase/decrease the amount of text. The items should expand and contract to accommodate the text."
};
var itemTemplate = ExampleTemplates.DynamicTextTemplate();
var collectionView = new CollectionView
{
ItemsLayout = itemsLayout,
ItemTemplate = itemTemplate,
AutomationId = "collectionview"
};
var generator = new ItemsSourceGenerator(collectionView, initialItems: 20);
layout.Children.Add(generator);
layout.Children.Add(instructions);
layout.Children.Add(collectionView);
Grid.SetRow(instructions, 1);
Grid.SetRow(collectionView, 2);
Content = layout;
generator.GenerateItems();
}
protected virtual void SetUpNewElement(TItemsView newElement)
{
if (newElement == null)
{
ItemsView = null;
return;
}
ItemsView = newElement;
ItemsView.PropertyChanged += OnElementPropertyChanged;
// TODO hartez 2018/06/06 20:49:14 Review whether we can just do this in the constructor
if (Tracker == null)
{
Tracker = new VisualElementTracker(this);
}
this.EnsureId();
UpdateItemsSource();
_layout = GetItemsLayout();
SetLayoutManager(SelectLayoutManager(_layout));
UpdateSnapBehavior();
UpdateBackgroundColor();
UpdateFlowDirection();
UpdateItemSpacing();
UpdateHorizontalScrollBarVisibility();
UpdateVerticalScrollBarVisibility();
// Keep track of the ItemsLayout's property changes
if (_layout != null)
{
_layout.PropertyChanged += LayoutPropertyChanged;
}
// Listen for ScrollTo requests
ItemsView.ScrollToRequested += ScrollToRequested;
_recyclerViewScrollListener = new RecyclerViewScrollListener <TItemsView, TItemsViewSource>(ItemsView, ItemsViewAdapter);
AddOnScrollListener(_recyclerViewScrollListener);
}
void SetUpNewElement(CollectionView newElement)
{
if (newElement == null)
{
return;
}
_layout = newElement.ItemsLayout;
_flowLayout = SelectLayout(_layout);
_collectionViewController = new CollectionViewController(newElement, _flowLayout);
SetNativeControl(_collectionViewController.View);
_collectionViewController.CollectionView.BackgroundColor = UIColor.Clear;
_collectionViewController.CollectionView.WeakDelegate = _flowLayout;
_collectionViewController.UpdateEmptyView();
// Listen for ScrollTo requests
newElement.ScrollToRequested += ScrollToRequested;
}
protected virtual LayoutManager SelectLayoutManager(IItemsLayout layoutSpecification)
{
switch (layoutSpecification)
{
case GridItemsLayout gridItemsLayout:
return CreateGridLayout(gridItemsLayout);
case LinearItemsLayout listItemsLayout:
var orientation = listItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal
? LinearLayoutManager.Horizontal
: LinearLayoutManager.Vertical;
return new LinearLayoutManager(Context, orientation, false);
}
// Fall back to plain old vertical list
// TODO hartez 2018/08/30 19:34:36 Log a warning when we have to fall back because of an unknown layout
return new LinearLayoutManager(Context);
}
public virtual void UpdateLayoutManager()
{
if (ItemsLayout != null)
{
ItemsLayout.PropertyChanged -= LayoutPropertyChanged;
}
ItemsLayout = GetItemsLayout();
// Keep track of the ItemsLayout's property changes
if (ItemsLayout != null)
{
ItemsLayout.PropertyChanged += LayoutPropertyChanged;
}
SetLayoutManager(SelectLayoutManager(ItemsLayout));
UpdateFlowDirection();
UpdateItemSpacing();
}
