PrimaryScrollControllerModifier class

Associates a ScrollController with a subtree.

When a ScrollView has ScrollView.primary set to true, the ScrollView uses of to inherit the PrimaryScrollController associated with its subtree.

A ScrollView that doesn't have a controller or the primary flag set will inherit the PrimarySCrollController, if shouldInherit allows it. By default shouldInherit is true for mobile platforms when the ScrollView has a scroll direction of Axis.vertical. This automatic inheritance can be configured with automaticallyInheritForPlatforms and scrollDirection.

Inheriting this ScrollController can provide default behavior for scroll views in a subtree. For example, the Scaffold uses this mechanism to implement the scroll-to-top gesture on iOS.

Another default behavior handled by the PrimaryScrollController is default ScrollActions. If a ScrollAction is not handled by an otherwise focused part of the application, the ScrollAction will be evaluated using the scroll view associated with a PrimaryScrollController, for example, when executing Shortcuts key events like page up and down.

See also:

Inheritance
Available extensions

Constructors

PrimaryScrollControllerModifier({Key? key, Widget? child, Key? modifierKey, ScrollController? controller, Set<TargetPlatform> automaticallyInheritForPlatforms = _kMobilePlatforms, Axis? scrollDirection = Axis.vertical})
Creates a widget that associates a ScrollController with a subtree.
const
PrimaryScrollControllerModifier.none({Key? key, Widget? child, Key? modifierKey})
Creates a subtree without an associated ScrollController.
const

Properties

automaticallyInheritForPlatforms → Set<TargetPlatform>
The TargetPlatforms this controller is configured for ScrollViews to automatically inherit.
final
controller → ScrollController?
The ScrollController associated with the subtree.
final
hashCode → int
The hash code for this object.
no setterinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
modifierKey → Key?
The actual key of the widget, which Modifier wrapped
finalinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
scrollDirection → Axis?
The Axis this controller is configured for ScrollViews to automatically inherit.
final

Methods

build(BuildContext context) → Widget
Describes the part of the user interface represented by this widget.
inherited
buildWithChild(BuildContext context, Widget? child) → Widget
A build method that receives an extra child parameter.
override
createElement() → SingleChildStatelessElement
Create a SingleChildStatelessElement
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
modified() → Modifier

Available on Widget, provided by the ModifierTransformer extension

Transform normal widget to Modifier
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, int wrapWidth = 65}) → 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