ReorderableListView class Null safety

A list whose items the user can interactively reorder by dragging.

This sample shows by dragging the user can reorder the items of the list. The onReorder parameter is required and will be called when a child widget is dragged to a new position.

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To create a local project with this code sample, run:
flutter create --sample=material.ReorderableListView.1 mysample

By default, on TargetPlatformVariant.desktop platforms each item will have a drag handle added on top of it that will allow the user to grab it to move the item. On TargetPlatformVariant.mobile, no drag handle will be added, but when the user long presses anywhere on the item it will start moving the item. Displaying drag handles can be controlled with ReorderableListView.buildDefaultDragHandles.

All list items must have a key.

This example demonstrates using the proxyDecorator callback to customize the appearance of a list item while it's being dragged.

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While a drag is underway, the widget returned by the proxyDecorator serves as a "proxy" (a substitute) for the item in the list. The proxy is created with the original list item as its child. The proxyDecorator in this example is similar to the default one except that it changes the proxy item's background color.
To create a local project with this code sample, run:
flutter create --sample=material.ReorderableListView.2 mysample

Inheritance

Constructors

ReorderableListView({Key? key, required List<Widget> children, required ReorderCallback onReorder, void onReorderStart(int index)?, void onReorderEnd(int index)?, double? itemExtent, Widget? prototypeItem, ReorderItemProxyDecorator? proxyDecorator, bool buildDefaultDragHandles = true, EdgeInsets? padding, Widget? header, Widget? footer, Axis scrollDirection = Axis.vertical, bool reverse = false, ScrollController? scrollController, bool? primary, ScrollPhysics? physics, bool shrinkWrap = false, double anchor = 0.0, double? cacheExtent, DragStartBehavior dragStartBehavior = DragStartBehavior.start, ScrollViewKeyboardDismissBehavior keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual, String? restorationId, Clip clipBehavior = Clip.hardEdge})
Creates a reorderable list from a pre-built list of widgets.
ReorderableListView.builder({Key? key, required IndexedWidgetBuilder itemBuilder, required int itemCount, required ReorderCallback onReorder, void onReorderStart(int index)?, void onReorderEnd(int index)?, double? itemExtent, Widget? prototypeItem, ReorderItemProxyDecorator? proxyDecorator, bool buildDefaultDragHandles = true, EdgeInsets? padding, Widget? header, Widget? footer, Axis scrollDirection = Axis.vertical, bool reverse = false, ScrollController? scrollController, bool? primary, ScrollPhysics? physics, bool shrinkWrap = false, double anchor = 0.0, double? cacheExtent, DragStartBehavior dragStartBehavior = DragStartBehavior.start, ScrollViewKeyboardDismissBehavior keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual, String? restorationId, Clip clipBehavior = Clip.hardEdge})
Creates a reorderable list from widget items that are created on demand.
const

Properties

anchor → double
The relative position of the zero scroll offset.
final
buildDefaultDragHandles → bool
If true: on desktop platforms, a drag handle is stacked over the center of each item's trailing edge; on mobile platforms, a long press anywhere on the item starts a drag.
final
cacheExtent → double?
The viewport has an area before and after the visible area to cache items that are about to become visible when the user scrolls.
final
clipBehavior → Clip
The content will be clipped (or not) according to this option.
final
dragStartBehavior → DragStartBehavior
Determines the way that drag start behavior is handled.
final
A non-reorderable footer item to show after the items of the list.
final
hashCode → int
The hash code for this object.
nonVirtual">@nonVirtualread-onlyinherited
A non-reorderable header item to show before the items of the list.
final
itemBuilder → IndexedWidgetBuilder
Called, as needed, to build list item widgets.
final
itemCount → int
The number of items in the list.
final
itemExtent → double?
If non-null, forces the children to have the given extent in the scroll direction.
final
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
keyboardDismissBehavior → ScrollViewKeyboardDismissBehavior
ScrollViewKeyboardDismissBehavior the defines how this ScrollView will dismiss the keyboard automatically.
final
onReorder → ReorderCallback
A callback used by the list to report that a list item has been dragged to a new location in the list and the application should update the order of the items.
final
onReorderEnd → (void Function?(int index)?)
A callback that is called when the dragged item is dropped.
final
onReorderStart → (void Function?(int index)?)
A callback that is called when an item drag has started.
final
padding → EdgeInsets?
The amount of space by which to inset the list contents.
final
physics → ScrollPhysics?
How the scroll view should respond to user input.
final
primary → bool?
Whether this is the primary scroll view associated with the parent PrimaryScrollController.
final
prototypeItem → Widget?
If non-null, forces the children to have the same extent as the given widget in the scroll direction.
final
proxyDecorator → ReorderItemProxyDecorator?
A callback that allows the app to add an animated decoration around an item when it is being dragged.
final
restorationId → String?
Restoration ID to save and restore the scroll offset of the scrollable.
final
reverse → bool
Whether the scroll view scrolls in the reading direction.
final
runtimeType → Type
A representation of the runtime type of the object.
read-onlyinherited
scrollController → ScrollController?
An object that can be used to control the position to which this scroll view is scrolled.
final
scrollDirection → Axis
The axis along which the scroll view scrolls.
final
shrinkWrap → bool
Whether the extent of the scroll view in the scrollDirection should be determined by the contents being viewed.
final

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<ReorderableListView>
Creates the mutable state for this widget at a given location in the tree.
override
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
protected">@protectedinherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
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

Operators

operator ==(Object other) → bool
The equality operator.
nonVirtual">@nonVirtualinherited