InfiniteScrollListView<T> class

A widget that provides infinite scrolling functionality to ListView or GridView.

This widget fetches data of type T using either of the fetchNext or fetchPrevious methods when the user scrolls the list or grid and calls the itemBuilder.

Each item's Widget has a Provider in its parent, and you can access each item's information using methods like context.read<T>() or context.read<InfiniteScrollItemInformation>(), etc.

If the item implements Listenable, the parent uses InheritedProvider to register listeners. This enables the detection of changes to the item and the rebuilding of the item accordingly.

It also supports pull-to-refresh functionality.

For example:

const int kMaxFetchCount = 20;
const int kItemMaxLength = 100;

InfiniteScrollListView<String>.list(
  initialIndex: () => 0,
  fetchPrev: (index, crossAxisCount) async {
    final tStartIndex = max(0, index - kMaxFetchCount + 1);
    final tFetchCount = index + 1 - tStartIndex;

    return List.generate(tFetchCount, (i) => 'Item ${tStartIndex + i}');
  },
  fetchNext: (index, crossAxisCount) async {
    final tFetchCount = min(kMaxFetchCount, kItemMaxLength - index);

    return List.generate(tFetchCount, (i) => 'Item ${index + i}');
  },
  canFetchPrev: (index) => index >= 0,
  canFetchNext: (index) => index < kItemMaxLength,
  itemBuilder: (context, item, index) {
    return ListTile(
      title: Text(item),
    );
  },
);
Inheritance

Constructors

InfiniteScrollListView.grid({Key? key, required Future<List<T>> fetchNext(int index, int crossAxisCount), Future<List<T>> fetchPrev(int index, int crossAxisCount)?, required Widget itemBuilder(BuildContext context, T item, int index), required SliverGridDelegate? gridDelegate, void onIndexChanged(int index, int crossAxisCount)?, Key? dataKey, ScrollPhysics? physics, Axis scrollDirection = Axis.vertical, bool? primary, int initialIndex()?, bool initialIndexNotFoundCallback(int index, bool giveup)?, ScrollController? controller, Clip clipBehavior = Clip.hardEdge, double? cacheExtent, List<Widget>? overlaySlivers, EdgeInsets? padding, bool canRefresh = true, Widget refreshIndicatorBuilder(BuildContext context, Widget child, Future<void> refresh())?, Widget? prefix, Widget? suffix, Widget? empty, Widget? loading, Widget? loadingMore, Widget errorBuilder(BuildContext context, Object error)?, void onRefresh()?, bool canFetchNext(int index)?, bool canFetchPrev(int index)?})
Creates an infinite scrolling grid view.
InfiniteScrollListView.list({Key? key, required Future<List<T>> fetchNext(int index, int crossAxisCount), Future<List<T>> fetchPrev(int index, int crossAxisCount)?, required Widget itemBuilder(BuildContext context, T item, int index), void onIndexChanged(int index, int crossAxisCount)?, Key? dataKey, ScrollPhysics? physics, Axis scrollDirection = Axis.vertical, bool? primary, int initialIndex()?, bool initialIndexNotFoundCallback(int index, bool giveup)?, ScrollController? controller, Clip clipBehavior = Clip.hardEdge, double? cacheExtent, List<Widget>? overlaySlivers, EdgeInsets? padding, bool canRefresh = true, Widget refreshIndicatorBuilder(BuildContext context, Widget child, Future<void> refresh())?, Widget? prefix, Widget? suffix, Widget? empty, Widget? loading, Widget? loadingMore, Widget errorBuilder(BuildContext context, Object error)?, void onRefresh()?, bool canFetchNext(int index)?, bool canFetchPrev(int index)?})
Creates an infinite scrolling list view.

Properties

cacheExtent → double?
The extent of the area in which content is cached.
final
canFetchNext → bool Function(int index)?
Determines whether more data can be fetched when scrolling forward.
final
canFetchPrev → bool Function(int index)?
Determines whether more data can be fetched when scrolling backward.
final
canRefresh → bool
Whether pull-to-refresh is enabled.
final
clipBehavior → Clip
How to clip overflowing content.
final
controller → ScrollController?
A controller for an infinite scroll list view.
final
dataKey → Key?
Changing this key resets the data and fetches data again starting from initialIndex.
final
empty → Widget?
Widget to display when the list is empty.
final
errorBuilder → Widget Function(BuildContext context, Object error)?
Builder to display an error message when data loading fails.
final
fetchNext → Future<List<T>> Function(int index, int crossAxisCount)
Function to fetch the next set of items when scrolling forward.
final
fetchPrev → Future<List<T>> Function(int index, int crossAxisCount)?
Function to fetch the previous set of items when scrolling backward.
final
gridDelegate → SliverGridDelegate?
The delegate that controls the layout of the grid tiles.
final
hashCode → int
The hash code for this object.
no setterinherited
initialIndex → int Function()?
Function that returns the initial index to scroll to.
final
initialIndexNotFoundCallback → bool Function(int index, bool giveup)?
Callback invoked when the index specified by initialIndex cannot be fetched by fetchNext during initialization (e.g., when fetchNext returns an empty List).
final
itemBuilder → Widget Function(BuildContext context, T item, int index)
Builder function to render each item in the list or grid.
final
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
loading → Widget?
Widget to display while the initial data is loading.
final
loadingMore → Widget?
Widget to display while loading more data.
final
onIndexChanged → void Function(int index, int crossAxisCount)?
Called when the list scroll ends and returns the topmost index of the list.
final
onRefresh → void Function()?
Callback when a refresh is triggered.
final
overlaySlivers → List<Widget>?
A list of slivers to overlay on top of the scroll view.
final
padding → EdgeInsets?
The amount of space by which to inset the children.
final
physics → ScrollPhysics?
How the scroll view should respond to user input.
final
prefix → Widget?
A widget to display before the list of items.
final
primary → bool?
Whether this is the primary scroll view associated with the parent PrimaryScrollController.
final
refreshIndicatorBuilder → Widget Function(BuildContext context, Widget child, Future<void> refresh())?
Builder for the refresh indicator widget.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
scrollDirection → Axis
The axis along which the scroll view scrolls.
final
suffix → Widget?
A widget to display after the list of items.
final

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<InfiniteScrollListView<T>>
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.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent 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, int wrapWidth = 65}) → 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.
inherited