Created
August 11, 2020 15:51
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| import 'package:flutter/widgets.dart'; | |
| import 'new_sb_base.dart'; | |
| class MyStreamBuilder<T> extends MyStreamBuilderBase<T, AsyncSnapshot<T>> { | |
| /// Creates a new [MyStreamBuilder] that builds itself based on the latest | |
| /// snapshot of interaction with the specified [stream] and whose build | |
| /// strategy is given by [builder]. | |
| /// | |
| /// The [initialData] is used to create the initial snapshot. | |
| /// | |
| /// The [builder] must not be null. | |
| const MyStreamBuilder({ | |
| Key key, | |
| this.initialData, | |
| Stream<T> stream, | |
| @required this.builder, | |
| }) : assert(builder != null), | |
| super(key: key, stream: stream); | |
| /// The build strategy currently used by this builder. | |
| /// | |
| /// This builder must only return a widget and should not have any side | |
| /// effects as it may be called multiple times. | |
| final AsyncWidgetBuilder<T> builder; | |
| /// The data that will be used to create the initial snapshot. | |
| /// | |
| /// Providing this value (presumably obtained synchronously somehow when the | |
| /// [Stream] was created) ensures that the first frame will show useful data. | |
| /// Otherwise, the first frame will be built with the value null, regardless | |
| /// of whether a value is available on the stream: since streams are | |
| /// asynchronous, no events from the stream can be obtained before the initial | |
| /// build. | |
| final T initialData; | |
| @override | |
| AsyncSnapshot<T> initial() => AsyncSnapshot<T>.withData(ConnectionState.none, initialData); | |
| @override | |
| AsyncSnapshot<T> afterConnected(AsyncSnapshot<T> current) => current.inState(ConnectionState.waiting); | |
| @override | |
| AsyncSnapshot<T> afterData(AsyncSnapshot<T> current, T data) { | |
| return AsyncSnapshot<T>.withData(ConnectionState.active, data); | |
| } | |
| @override | |
| AsyncSnapshot<T> afterError(AsyncSnapshot<T> current, Object error) { | |
| return AsyncSnapshot<T>.withError(ConnectionState.active, error); | |
| } | |
| @override | |
| AsyncSnapshot<T> afterDone(AsyncSnapshot<T> current) => current.inState(ConnectionState.done); | |
| @override | |
| AsyncSnapshot<T> afterDisconnected(AsyncSnapshot<T> current) => current.inState(ConnectionState.none); | |
| @override | |
| Widget build(BuildContext context, AsyncSnapshot<T> currentSummary) => builder(context, currentSummary); | |
| } |
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