CustomScrollView class

A ScrollView that creates custom scroll effects using slivers.

A CustomScrollView lets you supply slivers directly to create various scrolling effects, such as lists, grids, and expanding headers. For example, to create a scroll view that contains an expanding app bar followed by a list and a grid, use a list of three slivers: SliverAppBar, SliverList, and SliverGrid.

Widgets in these slivers must produce RenderSliver objects.

To control the initial scroll offset of the scroll view, provide a controller with its ScrollController.initialScrollOffset property set.

This sample code shows a scroll view that contains a flexible pinned app bar, a grid, and an infinite list.
  slivers: <Widget>[
    const SliverAppBar(
      pinned: true,
      expandedHeight: 250.0,
      flexibleSpace: FlexibleSpaceBar(
        title: Text('Demo'),
      gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
        maxCrossAxisExtent: 200.0,
        mainAxisSpacing: 10.0,
        crossAxisSpacing: 10.0,
        childAspectRatio: 4.0,
      delegate: SliverChildBuilderDelegate(
        (BuildContext context, int index) {
          return Container(
            color: Colors.teal[100 * (index % 9)],
            child: Text('Grid Item $index'),
        childCount: 20,
      itemExtent: 50.0,
      delegate: SliverChildBuilderDelegate(
        (BuildContext context, int index) {
          return Container(
            color: Colors.lightBlue[100 * (index % 9)],
            child: Text('List Item $index'),

By default, if items are inserted at the "top" of a scrolling container like ListView or CustomScrollView, the top item and all of the items below it are scrolled downwards. In some applications, it's preferable to have the top of the list just grow upwards, without changing the scroll position. This example demonstrates how to do that with a CustomScrollView with two SliverList children, and the set to the key of the bottom SliverList. The top one SliverList will grow upwards, and the bottom SliverList will grow downwards.
To create a local project with this code sample, run:
flutter create --sample=widgets.CustomScrollView.2 mysample


A CustomScrollView can allow Talkback/VoiceOver to make announcements to the user when the scroll state changes. For example, on Android an announcement might be read as "showing items 1 to 10 of 23". To produce this announcement, the scroll view needs three pieces of information:

  • The first visible child index.
  • The total number of children.
  • The total number of visible children.

The last value can be computed exactly by the framework, however the first two must be provided. Most of the higher-level scrollable widgets provide this information automatically. For example, ListView provides each child widget with a semantic index automatically and sets the semantic child count to the length of the list.

To determine visible indexes, the scroll view needs a way to associate the generated semantics of each scrollable item with a semantic index. This can be done by wrapping the child widgets in an IndexedSemantics.

This semantic index is not necessarily the same as the index of the widget in the scrollable, because some widgets may not contribute semantic information. Consider a ListView.separated: every other widget is a divider with no semantic information. In this case, only odd numbered widgets have a semantic index (equal to the index ~/ 2). Furthermore, the total number of children in this example would be half the number of widgets. (The ListView.separated constructor handles this automatically; this is only used here as an example.)

The total number of visible children can be provided by the constructor parameter semanticChildCount. This should always be the same as the number of widgets wrapped in IndexedSemantics.

See also:

  • SliverList, which is a sliver that displays linear list of children.
  • SliverFixedExtentList, which is a more efficient sliver that displays linear list of children that have the same extent along the scroll axis.
  • SliverGrid, which is a sliver that displays a 2D array of children.
  • SliverPadding, which is a sliver that adds blank space around another sliver.
  • SliverAppBar, which is a sliver that displays a header that can expand and float as the scroll view scrolls.
  • ScrollNotification and NotificationListener, which can be used to watch the scroll position without using a ScrollController.
  • IndexedSemantics, which allows annotating child lists with an index for scroll announcements.


CustomScrollView({Key key, Axis scrollDirection: Axis.vertical, bool reverse: false, ScrollController controller, bool primary, ScrollPhysics physics, bool shrinkWrap: false, Key center, double anchor: 0.0, double cacheExtent, List<Widget> slivers: const <Widget>[], int semanticChildCount, DragStartBehavior dragStartBehavior: DragStartBehavior.start, String restorationId, Clip clipBehavior: Clip.hardEdge})
Creates a ScrollView that creates custom scroll effects using slivers. [...]


anchor double
The relative position of the zero scroll offset. [...]
final, inherited
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. [...]
final, inherited
center Key
The first child in the GrowthDirection.forward growth direction. [...]
final, inherited
clipBehavior Clip
The content will be clipped (or not) according to this option. [...]
final, inherited
controller ScrollController
An object that can be used to control the position to which this scroll view is scrolled. [...]
final, inherited
dragStartBehavior DragStartBehavior
Determines the way that drag start behavior is handled. [...]
final, inherited
hashCode int
The hash code for this object. [...]
@nonVirtual, read-only, inherited
key Key
Controls how one widget replaces another widget in the tree. [...]
final, inherited
keyboardDismissBehavior ScrollViewKeyboardDismissBehavior
ScrollViewKeyboardDismissBehavior the defines how this ScrollView will dismiss the keyboard automatically.
final, inherited
physics ScrollPhysics
How the scroll view should respond to user input. [...]
final, inherited
primary bool
Whether this is the primary scroll view associated with the parent PrimaryScrollController. [...]
final, inherited
restorationId String
Restoration ID to save and restore the scroll offset of the scrollable. [...]
final, inherited
reverse bool
Whether the scroll view scrolls in the reading direction. [...]
final, inherited
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited
scrollDirection Axis
The axis along which the scroll view scrolls. [...]
final, inherited
semanticChildCount int
The number of children that will contribute semantic information. [...]
final, inherited
shrinkWrap bool
Whether the extent of the scroll view in the scrollDirection should be determined by the contents being viewed. [...]
final, inherited
slivers List<Widget>
The slivers to place inside the viewport.


build(BuildContext context) Widget
Describes the part of the user interface represented by this widget. [...]
buildSlivers(BuildContext context) List<Widget>
Build the list of widgets to place inside the viewport. [...]
buildViewport(BuildContext context, ViewportOffset offset, AxisDirection axisDirection, List<Widget> slivers) Widget
Build the viewport. [...]
@protected, inherited
createElement() StatelessElement
Creates a StatelessElement to manage this widget's location in the tree. [...]
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children. [...]
@protected, inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node. [...]
getDirection(BuildContext context) AxisDirection
Returns the AxisDirection in which the scroll view scrolls. [...]
@protected, inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed. [...]
toDiagnosticsNode({String name, DiagnosticsTreeStyle style}) DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep. [...]
toString({DiagnosticLevel minLevel:}) String
Returns a string representation of this object.
toStringDeep({String prefixLineOne: '', String prefixOtherLines, DiagnosticLevel minLevel: DiagnosticLevel.debug}) String
Returns a string representation of this node and its descendants. [...]
toStringShallow({String joiner: ', ', DiagnosticLevel minLevel: DiagnosticLevel.debug}) String
Returns a one-line detailed description of the object. [...]
toStringShort() String
A short, textual description of this widget.


operator ==(Object other) bool
The equality operator. [...]
@nonVirtual, inherited