RxPaginatedBuilder<B extends RxBlocTypeBase, T> class

RxPaginatedBuilder provides the flexibility and simplicity of presentation of paginated data with the use of RxBlocs inside the RxBloc ecosystem. It was created with the intention of presenting a list of data that can be loaded once that list has reached its end, or can be refreshed using a pull-to-refresh feature (see RxPaginatedBuilder.withRefreshIndicator).

In order to make use of the RxPaginatedBuilder, you first need to specify the following required parameters:

• state is the state of the BLoC that will be listened for changes. The state is a Stream<PaginatedList<T>> where T is the type of the data that is being paginated.
• buildSuccess is a callback which is invoked when the state stream produces PaginatedList with non empty PaginatedList.list or all further data loads, such as next page loads.
• buildError Callback which is invoked when the state stream produces PaginatedList where PaginatedList.error is not null.
• buildLoading is a callback which is invoked when the state stream produces PaginatedList where PaginatedList.isInitialLoading is true.
• onBottomScrolled is a callback that is executed once the end of the list is reached and there is next page. This can be, for instance, used for fetching the next page of data.

RxPaginatedBuilder also comes with additional optional parameters that can be adjusted to you needs.

The wrapperBuilder method is a builder method with the intention of creating a wrapper widget around the child widget built using the main buildSuccess method. The wrapperBuilder method gives you access to the BuildContext, BLoC containing the state that is listened and the Widget that is build with the builder method. This method can be used for adding additional functionality or help in cases when the built child widget is needed beforehand.

You can manage the execution of the onBottomScrolled parameter by enabling or disabling it via the enableOnBottomScrolledCallback.

Additionally, you can define the minimum scroll threshold which will execute the onBottomScrolled callback by changing the value of scrollThreshold. The default value of the scroll threshold is 100 pixels.

The RxPaginatedBuilder also provides the ability to react to scrolling via the onScrolled callback, with a parameter telling whether the user is or has stopped scrolling.

There may be cases where you have a reference to the BLoC that is used by the RxPaginatedBuilder. By specifying the bloc parameter you remove the need to perform a lookup for that BLoC in the widget tree, improving the performance by a small bit.

Here is an example of what a RxPaginatedBloc using a UserBloc looks like:

RxPaginatedBuilder<UserBlocType, User>(
  state: (bloc) => bloc.states.paginatedUsers,
  onBottomScrolled: (bloc) => bloc.events.loadNextPage(),
  buildSuccess: (context, list, bloc) => ListView.builder(
    itemBuilder: (context, index) {
      final user = list.getItem(index);

      if (user == null) {
        return const YourProgressIndicator();
      }

      return YourListTile(user: user);
    },
    itemCount: list.itemCount,
  ),
  buildLoading: (context, list, bloc) =>
    const YourProgressIndicator(),
  buildError: (context, list, bloc) =>
    YourErrorWidget(error: list.error!),
);

Sometimes, you may want to have a working pagination and pull-to-refresh without spending too much time on it. Using the RxPaginatedBuilder.withRefreshIndicator gives you access to a Refresh Indicator straight out of the box.

Along with the required parameters of the default implementation, RxPaginatedBuilder.withRefreshIndicator gets rid of the wrapperBuilder but introduces a new required parameter onRefresh. The onRefresh callback is triggered once a pull-to-refresh has been performed. The callback, containing the BLoC as a parameter, should return a future, which once complete will make the refresh indicator disappear.

Here is an example of what a RxPaginatedBloc using a UserBloc looks like using the withRefreshIndicator constructor :

RxPaginatedBuilder<UserBlocType, User>.withRefreshIndicator(
  state: (bloc) => bloc.states.paginatedList,
  onBottomScrolled: (bloc) => bloc.events.loadPage(),
  onRefresh: (bloc) async {
    bloc.events.loadPage(reset: true);
    return bloc.states.refreshDone;
  },
  buildSuccess: (context, list, bloc) => ListView.builder(
    itemBuilder: (context, index) {
      final user = list.getItem(index);

      if (user == null) {
        return const YourProgressIndicator();
      }

      return YourListTile(user: user);
    },
    itemCount: list.itemCount,
  ),
  buildLoading: (context, list, bloc) =>
    const YourProgressIndicator(),
  buildError: (context, list, bloc) =>
    YourErrorWidget(error: list.error!),
)

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatefulWidget
• RxPaginatedBuilder

Constructors

RxPaginatedBuilder({required Stream<PaginatedList<T>> state(B), required Widget buildSuccess(BuildContext, PaginatedList<T>, B), required Widget buildError(BuildContext, PaginatedList<T>, B), required Widget buildLoading(BuildContext, PaginatedList<T>?, B), required void onBottomScrolled(B), Widget wrapperBuilder(BuildContext, B, Widget)?, dynamic onScrolled(bool)?, double scrollThreshold = 100.0, bool enableOnBottomScrolledCallback = true, B? bloc, Key? key})

RxPaginatedBuilder default constructor

const

RxPaginatedBuilder.withRefreshIndicator({required Stream<PaginatedList<T>> state(B), required Widget buildSuccess(BuildContext, PaginatedList<T>, B), required Widget buildError(BuildContext, PaginatedList<T>, B), required Widget buildLoading(BuildContext, PaginatedList<T>?, B), required Future<void> onRefresh(B), required void onBottomScrolled(B), dynamic onScrolled(bool)?, B? bloc, double scrollThreshold = 100, bool enableOnBottomScrolledCallback = true})

RxPaginatedBuilder constructor with refresh indicator. An addition to the default constructor is the requirement for the onRefresh callback which will be executed once the refreshed using the pull-down to refresh feature.

factory

Properties

bloc → B?

The bloc (Business Logic of Component) that is used. If none specified a lookup is performed in the widget tree to find the nearest ancestor.

final

buildError → Widget Function(BuildContext, PaginatedList<T>, B)

Callback which is invoked when the state stream produces PaginatedList where PaginatedList.error is not null.

final

buildLoading → Widget Function(BuildContext, PaginatedList<T>?, B)

Callback which is invoked when the state stream produces PaginatedList where PaginatedList.isInitialLoading is true.

final

buildSuccess → Widget Function(BuildContext, PaginatedList<T>, B)

Callback which is invoked when the state stream produces PaginatedList with non empty PaginatedList.list or all further data loads, such as next page loads.

final

enableOnBottomScrolledCallback → bool

When set to true onBottomScrolled is executed once the user scrolls at the bottom of the list.

final

hashCode → int

The hash code for this object.

no setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

onBottomScrolled → void Function(B)

Callback triggered once the user gets to the bottom of the list while scrolling when a threshold has been passed. This callback is triggered only if the enableOnBottomScrolledCallback is set to true and the fetched items are less than the total count.

final

onScrolled → (dynamic Function(bool)?)

Optional callback triggered while the user is scrolling the list.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

scrollThreshold → double

Minimum threshold (defaults to 100 pixels) that needs to be passed in order for the onBottomScrolled to be triggered.

final

state → Stream<PaginatedList<T>> Function(B)

The state of the BLoC to listen to for changes in data. The state is represented as a Stream of PaginatedList, which contains individual items.

final

wrapperBuilder → (Widget Function(BuildContext, B, Widget)?)

Optional builder method that is intended for creation of a wrapper widget on top of the widget built using the buildSuccess method. This can be handy when implementing onRefresh or any other features requiring the widget beforehand (for example for building a RefreshIndicator around the widget).

final

Methods

createElement() → StatefulElement

Creates a StatefulElement to manage this widget's location in the tree.

inherited

createState() → RxPaginatedBuilderState<B, 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}) → 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