PrimaryScrollController class Null safety

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.

Constructors

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

Properties

automaticallyInheritForPlatforms → Set<TargetPlatform>: The TargetPlatforms this controller is configured for ScrollViews to automatically inherit.
final
child → Widget: The widget below this widget in the tree.
final, inherited
controller → ScrollController?: The ScrollController associated with the subtree.
final
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
runtimeType → Type: A representation of the runtime type of the object.
read-only, inherited
scrollDirection → Axis?: The Axis this controller is configured for ScrollViews to automatically inherit.
final

Methods

createElement() → InheritedElement: Inflates this configuration to a concrete instance.
inherited
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.
override
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 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
updateShouldNotify(covariant PrimaryScrollController oldWidget) → bool: Whether the framework should notify widgets that inherit from this widget.
override

Operators

operator ==(Object other) → bool: The equality operator.
@nonVirtual, inherited

Static Methods

of(BuildContext context) → ScrollController?: Returns the ScrollController most closely associated with the given context.
shouldInherit(BuildContext context, Axis scrollDirection) → bool: Returns true if this PrimaryScrollController is configured to be automatically inherited for the current TargetPlatform and the given Axis.

Flutter
widgets
PrimaryScrollController class