TreeReorderController<TKey, TData> class

Controls a drag-and-drop reorder over a TreeController.

Owns an autoscroll Ticker for edge-zone scrolling. Not usable with a comparator-based controller (auto-sort would override user order) — the constructor throws ArgumentError in that case.

Extends ChangeNotifier: listeners are notified whenever currentTarget changes or the drag session begins/ends. Consumers that need to repaint per-pointer-move (like the built-in drop indicator) subscribe here instead of polling per-frame.

Inheritance

Constructors

TreeReorderController({required TreeController<TKey, TData> treeController, required TickerProvider vsync, bool canReorder(TKey key)?, bool canAcceptDrop({int? index, required TKey movingKey, TKey? newParent})?, Duration slideDuration = const Duration(milliseconds: 220), Curve slideCurve = Curves.easeOutCubic, double autoScrollEdgeZone = 48.0, double autoScrollMaxVelocity = 1200.0})

Properties

autoScrollEdgeZone → double
Height in pixels from each viewport edge within which the pointer triggers autoscroll. Velocity ramps linearly from 0 at the zone's inner edge to autoScrollMaxVelocity at the viewport edge.
final
autoScrollMaxVelocity → double
Peak autoscroll velocity in logical pixels per second.
final
canAcceptDrop → bool Function({int? index, required TKey movingKey, TKey? newParent})?
If set, rejected drop targets are filtered out. Receives the dragged key, the candidate new parent, and the final-list index.
final
canReorder → bool Function(TKey key)?
If set, rows for which this returns false cannot be dragged.
final
currentTarget → TreeDropTarget<TKey>?
The current drop target, or null if the pointer is outside any row.
no setter
draggedKey → TKey?
The currently-dragged key, or null if no drag is active.
no setter
hashCode → int
The hash code for this object.
no setterinherited
hasListeners → bool
Whether any listeners are currently registered.
no setterinherited
isDragging → bool
Whether a drag is currently in flight.
no setter
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
slideCurve → Curve
Curve of the FLIP slide animation.
final
slideDuration → Duration
Duration of the FLIP slide animation on commit.
final
treeController → TreeController<TKey, TData>
The tree controller to mutate on drop.
final

Methods

addListener(VoidCallback listener) → void
Register a closure to be called when the object changes.
inherited
cancelDrag() → void
Aborts the current drag without mutating the tree.
dispose() → void
Releases the autoscroll ticker. Call from the owning widget's dispose.
override
endDrag() → Future<void>
Commits the drop: mutates treeController (via TreeController.moveNode, TreeController.reorderChildren, or TreeController.reorderRoots) and starts the FLIP slide animation to interpolate old → new positions.
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
startDrag({required TKey key, required RenderSliverTree<TKey, TData> renderObject, required ScrollableState scrollable, required double indentPerDepth, required Offset pointerGlobal}) → void
Begins a drag session for key.
toString() → String
A string representation of this object.
inherited
updateDrag(Offset pointerGlobal) → void
Updates the pointer position. Re-resolves the drop target and starts / stops the autoscroll ticker as needed.

Operators

operator ==(Object other) → bool
The equality operator.
inherited