FixedExtentScrollController class
A controller for scroll views whose items have the same size.
Similar to a standard ScrollController but with the added convenience mechanisms to read and go to item indices rather than a raw pixel scroll offset.
See also:
- ListWheelScrollView, a scrollable view widget with fixed size items that this widget controls.
- FixedExtentMetrics, the
metricsproperty exposed by ScrollNotification from ListWheelScrollView which can be used to listen to the current item index on a push basis rather than polling the FixedExtentScrollController.
- Inheritance
-
- Object
- ChangeNotifier
- ScrollController
- FixedExtentScrollController
Constructors
- FixedExtentScrollController({int initialItem = 0, ScrollControllerCallback? onAttach, ScrollControllerCallback? onDetach})
- Creates a scroll controller for scrollables whose items have the same size.
Properties
- debugLabel → String?
-
A label that is used in the toString output. Intended to aid with
identifying scroll controller instances in debug output.
finalinherited
- hasClients → bool
-
Whether any ScrollPosition objects have attached themselves to the
ScrollController using the attach method.
no setterinherited
- hashCode → int
-
The hash code for this object.
no setterinherited
- hasListeners → bool
-
Whether any listeners are currently registered.
no setterinherited
- initialItem → int
-
The page to show when first creating the scroll view.
final
- initialScrollOffset → double
-
The initial value to use for offset.
no setterinherited
- keepScrollOffset → bool
-
Each time a scroll completes, save the current scroll offset with
PageStorage and restore it if this controller's scrollable is recreated.
finalinherited
- offset → double
-
The current scroll offset of the scrollable widget.
no setterinherited
- onAttach → ScrollControllerCallback?
-
Called when a ScrollPosition is attached to the scroll controller.
finalinherited
- onDetach → ScrollControllerCallback?
-
Called when a ScrollPosition is detached from the scroll controller.
finalinherited
- position → ScrollPosition
-
Returns the attached ScrollPosition, from which the actual scroll offset
of the ScrollView can be obtained.
no setterinherited
-
positions
→ Iterable<
ScrollPosition> -
The currently attached positions.
no setterinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- selectedItem → int
-
The currently selected item index that's closest to the center of the viewport.
no setter
Methods
-
addListener(
VoidCallback listener) → void -
Register a closure to be called when the object changes.
inherited
-
animateTo(
double offset, {required Duration duration, required Curve curve}) → Future< void> -
Animates the position from its current value to the given value.
inherited
-
animateToItem(
int itemIndex, {required Duration duration, required Curve curve}) → Future< void> - Animates the controlled scroll view to the given item index.
-
attach(
ScrollPosition position) → void -
Register the given position with this controller.
inherited
-
createScrollPosition(
ScrollPhysics physics, ScrollContext context, ScrollPosition? oldPosition) → ScrollPosition -
Creates a ScrollPosition for use by a Scrollable widget.
override
-
debugFillDescription(
List< String> description) → void -
Add additional information to the given description for use by toString.
inherited
-
detach(
ScrollPosition position) → void -
Unregister the given position with this controller.
inherited
-
dispose(
) → void -
Discards any resources used by the object. After this is called, the
object is not in a usable state and should be discarded (calls to
addListener will throw after the object is disposed).
inherited
-
jumpTo(
double value) → void -
Jumps the scroll position from its current value to the given value,
without animation, and without checking if the new value is in range.
inherited
-
jumpToItem(
int itemIndex) → void - Changes which item index is centered in the controlled scroll view.
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
notifyListeners(
) → void -
Call all the registered listeners.
inherited
-
removeListener(
VoidCallback listener) → void -
Remove a previously registered closure from the list of closures that are
notified when the object changes.
inherited
-
toString(
) → String -
A string representation of this object.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited