scrollable_positioned_list

A flutter list that allows scrolling to a specific item in the list.

Also allows determining what items are currently visible.

Usage

A ScrollablePositionedList works much like the builder version of ListView except that the list can be scrolled or jumped to a specific item.

Example

A ScrollablePositionedList can be created with:

final ItemScrollController itemScrollController = ItemScrollController();
final ItemPositionsListener itemPositionsListener = ItemPositionsListener.create();
final ScrollOffsetListener scrollOffsetListener = ScrollOffsetListener.create()

ScrollablePositionedList.builder(
  itemCount: 500,
  itemBuilder: (context, index) => Text('Item $index'),
  itemScrollController: itemScrollController,
  itemPositionsListener: itemPositionsListener,
  scrollOffsetListener: scrollOffsetListener,
);

One then can scroll to a particular item with:

itemScrollController.scrollTo(
  index: 150,
  duration: Duration(seconds: 2),
  curve: Curves.easeInOutCubic);

or jump to a particular item with:

itemScrollController.jumpTo(index: 150);

One can monitor what items are visible on screen with:

itemPositionsListener.itemPositions.addListener(() => ...);

Changes in scroll position can be monitored with:

scrollOffsetListener.changes.listen((event) => ...)

see ScrollSum in this test for an example of how the current offset can be calculated from the stream of scroll change deltas. This feature is new and experimental.

A full example can be found in the example folder.

This is not an officially supported Google product.