A virtual viewport onto an extremely large or infinite list of equally sized children.
LazyListViewport differs from ListViewport in that LazyListViewport uses an ItemListBuilder to lazily create children. That makes LazyListViewport suitable for an extremely large or infinite list of children but also makes it more verbose than ListViewport.
LazyListViewport differs from LazyBlockViewport in that LazyListViewport requires each of its children to be the same size. That makes LazyListViewport more efficient but less flexible than LazyBlockViewport.
Used by ScrollableLazyList.
See also:
- Mixes-in
- VirtualViewportFromBuilder
Constructors
- LazyListViewport({ExtentsChangedCallback onExtentsChanged, double scrollOffset: 0.0, Axis mainAxis: Axis.vertical, ViewportAnchor anchor: ViewportAnchor.start, @required double itemExtent, EdgeInsets padding, int itemCount, @required ItemListBuilder itemBuilder })
-
Creates a virtual viewport onto an extremely large or infinite list of equally sized children.
Properties
- itemBuilder → ItemListBuilder
-
read-only
- itemCount → int
-
read-only
- anchor → ViewportAnchor
-
Whether to place first child at the start of the container or the last child at the end of the container, when the viewport has not been offset.
read-only, inherited - hashCode → int
-
Get a hash code for this object.
read-only, inherited - itemExtent → double
-
The height of each item if
scrollDirectionis Axis.vertical, otherwise the width of each item.read-only, inherited - itemsWrap → bool
-
Whether the first item should be revealed after scrolling past the last item.
read-only, inherited - key → Key
-
Controls how one widget replaces another widget in the tree.
read-only, inherited - mainAxis → Axis
-
The direction in which the children are permitted to be larger than the viewport.
read-only, inherited - onExtentsChanged → ExtentsChangedCallback
-
Called when the interior or exterior dimensions of the viewport change.
read-only, inherited - padding → EdgeInsets
-
The amount of space by which to inset the children inside the viewport.
read-only, inherited - runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited - scrollOffset → double
-
The
startOffsetwithout taking thepaddinginto account.read-only, inherited - startOffset → double
-
read-only, inherited
Operators
-
operator ==(
other) → bool -
The equality operator.
inherited
Methods
-
createElement(
) → _VirtualListViewportElement -
RenderObjectWidgets always inflate to a
RenderObjectElementsubclass.inherited -
createRenderObject(
BuildContext context) → RenderList -
Creates an instance of the
RenderObjectclass that thisRenderObjectWidgetrepresents, using the configuration described by thisRenderObjectWidget.inherited -
debugFillDescription(
List<String> description) → void -
Add additional information to the given description for use by toString.
inherited -
didUnmountRenderObject(
RenderObject renderObject) → void -
A render object previously associated with this widget has been removed from the tree. The given RenderObject will be of the same type as returned by this object's createRenderObject.
inherited -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a non-existent method or property is accessed.
inherited -
toString(
) → String -
Returns a string representation of this object.
inherited -
toStringShort(
) → String -
A short, textual description of this widget.
inherited -
updateRenderObject(
BuildContext context, RenderObject renderObject) → void -
Copies the configuration described by this RenderObjectWidget to the given RenderObject, which will be of the same type as returned by this object's createRenderObject.
inherited