ShrinkWrappingViewport class

A widget that is bigger on the inside and shrink wraps its children in the main axis.

ShrinkWrappingViewport displays a subset of its children according to its own dimensions and the given offset. As the offset varies, different children are visible through the viewport.

ShrinkWrappingViewport differs from Viewport in that Viewport expands to fill the main axis whereas ShrinkWrappingViewport sizes itself to match its children in the main axis. This shrink wrapping behavior is expensive because the children, and hence the viewport, could potentially change size whenever the offset changes (e.g., because of a collapsing header).

ShrinkWrappingViewport cannot contain box children directly. Instead, use a SliverList, SliverFixedExtentList, SliverGrid, or a SliverToBoxAdapter, for example.

See also:

Inheritance

Constructors

ShrinkWrappingViewport({Key key, AxisDirection axisDirection: AxisDirection.down, AxisDirection crossAxisDirection, @required ViewportOffset offset, List<Widget> slivers: const [] })
Creates a widget that is bigger on the inside and shrink wraps its children in the main axis. [...]

Properties

axisDirection → AxisDirection
The direction in which the offset's ViewportOffset.pixels increases. [...]
final
crossAxisDirection → AxisDirection
The direction in which child should be laid out in the cross axis. [...]
final
offset → ViewportOffset
Which part of the content inside the viewport should be visible. [...]
final
children → List<Widget>
The widgets below this widget in the tree. [...]
final, inherited
hashCode → int
The hash code for this object. [...]
read-only, inherited
key → Key
Controls how one widget replaces another widget in the tree. [...]
final, inherited
runtimeType → Type
A representation of the runtime type of the object.
read-only, inherited

Methods

createRenderObject(BuildContext context) → RenderShrinkWrappingViewport
Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget. [...]
override
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node. [...]
override
updateRenderObject(BuildContext context, covariant RenderShrinkWrappingViewport 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. [...]
override
createElement() → MultiChildRenderObjectElement
RenderObjectWidgets always inflate to a RenderObjectElement subclass.
inherited
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children. [...]
@protected, inherited
didUnmountRenderObject(covariant 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.
@protected, inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent 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 toStringDeep. [...]
inherited
toString({DiagnosticLevel minLevel: DiagnosticLevel.debug }) → String
Returns 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 ==(dynamic other) → bool
The equality operator. [...]
inherited