PrimaryScrollController class Null safety
Associates a ScrollController with a subtree.
When a ScrollView has ScrollView.primary set to true and is not given an explicit ScrollController, the ScrollView uses of to find the ScrollController associated with its subtree.
This mechanism can be used to 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
- ProxyWidget
- InheritedWidget
- PrimaryScrollController
Constructors
- PrimaryScrollController({Key? key, required ScrollController controller, 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
- 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
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. [...]