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:

• ScrollAction, an Action that scrolls the Scrollable that encloses the current primaryFocus or is attached to the PrimaryScrollController.
• Shortcuts, a widget that establishes a ShortcutManager to be used by its descendants when invoking an Action via a keyboard key combination that maps to an Intent.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• SingleChildStatelessModifier
• PrimaryScrollControllerModifier

Available extensions

• ModifierTransformer

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 setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

modifierKey → Key?

The actual key of the widget, which Modifier wrapped

final, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

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

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