drag_drop library

Classes

UiDraggable<T extends Object>: A typed drag source for arbitrary content.
UiDragHandle: A 44px grip with focus indication, pointer dragging and semantic move actions. Focus the handle and press Arrow Up/Down to move one position.
UiDragPreview: Shared lifted surface for custom drag feedback and sortable proxies.
UiDropRegion<T extends Object>: Typed destination with explicit acceptance and token-driven boundary feedback.
UiReorderableList<T>: Controlled vertical sorting with stable keys, auto-scroll and keyboard moves.

UiDragActivation: Gesture policy for an in-app drag. Adaptive waits on touch/stylus and starts immediately with a mouse, preserving touch scrolling.
UiDropState: Local destination state; incompatible payload types never activate a region.

UiDropRegionBuilder = Widget Function(BuildContext context, UiDropState state)
UiReorderableItemBuilder<T> = Widget Function(BuildContext context, T item, int index, Widget handle): The builder receives a fully wired handle; place it beside any custom content.