AlignedGridView class
A scrollable, 2D array of widgets placed according to the aligned layout.
The main axis direction of a grid is the direction in which it scrolls (the scrollDirection).
The most commonly used grid layouts are AlignedGridView.count, which creates a layout with a fixed number of tiles in the cross axis, and AlignedGridView.extent, which creates a layout with tiles that have a maximum cross-axis extent. A custom SliverSimpleGridDelegate can produce an arbitrary 2D arrangement of children.
To create a linear array of children, use a ListView.
To control the initial scroll offset of the scroll view, provide a controller with its ScrollController.initialScrollOffset property set.
Transitioning to CustomScrollView
A AlignedGridView is basically a CustomScrollView with a single SliverAlignedGrid in its CustomScrollView.slivers property.
If AlignedGridView is no longer sufficient, for example because the scroll view is to have both a grid and a list, or because the grid is to be combined with a SliverAppBar, etc, it is straight-forward to port code from using AlignedGridView to using CustomScrollView directly.
The key, scrollDirection, reverse, controller, primary, physics, and shrinkWrap properties on AlignedGridView map directly to the identically named properties on CustomScrollView.
The CustomScrollView.slivers property should be a list containing just a SliverAlignedGrid.
The AlignedGridView.count and AlignedGridView.extent constructors create custom grid delegates, and have equivalently named constructors on SliverAlignedGrid to ease the transition: SliverAlignedGrid.count and SliverAlignedGrid.extent respectively.
The padding property corresponds to having a SliverPadding in the CustomScrollView.slivers property instead of the grid itself, and having the SliverGrid instead be a child of the SliverPadding.
Once code has been ported to use CustomScrollView, other slivers, such as SliverList or SliverAppBar, can be put in the CustomScrollView.slivers list.
By default, AlignedGridView will automatically pad the limits of the grids's scrollable to avoid partial obstructions indicated by MediaQuery's padding. To avoid this behavior, override with a zero padding property.
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- StatelessWidget
- ScrollView
- BoxScrollView
- AlignedGridView
Constructors
- AlignedGridView.count({Key? key, Axis scrollDirection = Axis.vertical, bool reverse = false, ScrollController? controller, bool? primary, ScrollPhysics? physics, bool shrinkWrap = false, EdgeInsetsGeometry? padding, required int crossAxisCount, double mainAxisSpacing = 0.0, double crossAxisSpacing = 0.0, required NullableIndexedWidgetBuilder itemBuilder, int? itemCount, bool addAutomaticKeepAlives = true, bool addRepaintBoundaries = true, double? cacheExtent, int? semanticChildCount, DragStartBehavior dragStartBehavior = DragStartBehavior.start, ScrollViewKeyboardDismissBehavior keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual, String? restorationId, Clip clipBehavior = Clip.hardEdge})
- Creates a scrollable, 2D array of widgets with a fixed number of tiles in the cross axis.
- AlignedGridView.custom({Key? key, Axis scrollDirection = Axis.vertical, bool reverse = false, ScrollController? controller, bool? primary, ScrollPhysics? physics, bool shrinkWrap = false, EdgeInsetsGeometry? padding, required SliverSimpleGridDelegate gridDelegate, required NullableIndexedWidgetBuilder itemBuilder, int? itemCount, bool addAutomaticKeepAlives = true, bool addRepaintBoundaries = true, double mainAxisSpacing = 0.0, double crossAxisSpacing = 0.0, double? cacheExtent, int? semanticChildCount, DragStartBehavior dragStartBehavior = DragStartBehavior.start, ScrollViewKeyboardDismissBehavior keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual, String? restorationId, Clip clipBehavior = Clip.hardEdge})
-
Creates a scrollable, 2D array of widgets with both a custom
SliverSimpleGridDelegate.
const
- AlignedGridView.extent({Key? key, Axis scrollDirection = Axis.vertical, bool reverse = false, ScrollController? controller, bool? primary, ScrollPhysics? physics, bool shrinkWrap = false, EdgeInsetsGeometry? padding, required double maxCrossAxisExtent, double mainAxisSpacing = 0.0, double crossAxisSpacing = 0.0, required NullableIndexedWidgetBuilder itemBuilder, int? itemCount, bool addAutomaticKeepAlives = true, bool addRepaintBoundaries = true, double? cacheExtent, int? semanticChildCount, DragStartBehavior dragStartBehavior = DragStartBehavior.start, ScrollViewKeyboardDismissBehavior keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual, String? restorationId, Clip clipBehavior = Clip.hardEdge})
- Creates a scrollable, 2D array of widgets with tiles that each have a maximum cross-axis extent.
Properties
- addAutomaticKeepAlives → bool
-
Whether to wrap each child in an AutomaticKeepAlive.
final
- addRepaintBoundaries → bool
-
Whether to wrap each child in a RepaintBoundary.
final
- anchor → double
-
The relative position of the zero scroll offset.
finalinherited
- cacheExtent → double?
-
The viewport has an area before and after the visible area to cache items
that are about to become visible when the user scrolls.
finalinherited
- center → Key?
-
The first child in the GrowthDirection.forward growth direction.
finalinherited
- clipBehavior → Clip
-
The content will be clipped (or not) according to this option.
finalinherited
- controller → ScrollController?
-
An object that can be used to control the position to which this scroll
view is scrolled.
finalinherited
- crossAxisSpacing → double
-
The number of pixels between each child along the cross axis.
final
- dragStartBehavior → DragStartBehavior
-
Determines the way that drag start behavior is handled.
finalinherited
- gridDelegate → SliverSimpleGridDelegate
-
A delegate that controls the layout of the children within the
AlignedGridView.
final
- hashCode → int
-
The hash code for this object.
no setterinherited
- itemBuilder → NullableIndexedWidgetBuilder
-
Called to build children for the sliver.
final
- itemCount → int?
-
The total number of children this delegate can provide.
final
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- keyboardDismissBehavior → ScrollViewKeyboardDismissBehavior
-
ScrollViewKeyboardDismissBehavior the defines how this ScrollView will
dismiss the keyboard automatically.
finalinherited
- mainAxisSpacing → double
-
The number of pixels between each child along the main axis.
final
- padding → EdgeInsetsGeometry?
-
The amount of space by which to inset the children.
finalinherited
- physics → ScrollPhysics?
-
How the scroll view should respond to user input.
finalinherited
- primary → bool?
-
Whether this is the primary scroll view associated with the parent
PrimaryScrollController.
finalinherited
- restorationId → String?
-
Restoration ID to save and restore the scroll offset of the scrollable.
finalinherited
- reverse → bool
-
Whether the scroll view scrolls in the reading direction.
finalinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- scrollBehavior → ScrollBehavior?
-
A ScrollBehavior that will be applied to this widget individually.
finalinherited
- scrollDirection → Axis
-
The Axis along which the scroll view's offset increases.
finalinherited
- semanticChildCount → int?
-
The number of children that will contribute semantic information.
finalinherited
- shrinkWrap → bool
-
Whether the extent of the scroll view in the scrollDirection should be
determined by the contents being viewed.
finalinherited
Methods
-
build(
BuildContext context) → Widget -
Describes the part of the user interface represented by this widget.
inherited
-
buildChildLayout(
BuildContext context) → Widget -
Subclasses should override this method to build the layout model.
override
-
buildSlivers(
BuildContext context) → List< Widget> -
Build the list of widgets to place inside the viewport.
inherited
-
buildViewport(
BuildContext context, ViewportOffset offset, AxisDirection axisDirection, List< Widget> slivers) → Widget -
Build the viewport.
inherited
-
createElement(
) → StatelessElement -
Creates a StatelessElement to manage this widget's location in the tree.
inherited
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of
DiagnosticsNode
objects describing this node's children.inherited -
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node.
inherited
-
getDirection(
BuildContext context) → AxisDirection -
Returns the AxisDirection in which the scroll view scrolls.
inherited
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
toDiagnosticsNode(
{String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode -
Returns a debug representation of the object that is used by debugging
tools and by DiagnosticsNode.toStringDeep.
inherited
-
toString(
{DiagnosticLevel minLevel = DiagnosticLevel.info}) → String -
A string representation of this object.
inherited
-
toStringDeep(
{String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String -
Returns a string representation of this node and its descendants.
inherited
-
toStringShallow(
{String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String -
Returns a one-line detailed description of the object.
inherited
-
toStringShort(
) → String -
A short, textual description of this widget.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited