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Add flutter_web samples (#75)
This commit is contained in:
Kevin Moore
committed by
Andrew Brogdon
Andrew Brogdon
parent
42f2dce01b
commit
3fe927cb29
513
web/vision_challenge/lib/packages/flutter_redux.dart
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513
web/vision_challenge/lib/packages/flutter_redux.dart
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// Package flutter_redux:
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// https://pub.dev/packages/flutter_redux
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import 'dart:async';
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import 'package:flutter_web/widgets.dart';
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import 'package:meta/meta.dart';
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import 'redux.dart';
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/// Provides a Redux [Store] to all descendants of this Widget. This should
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/// generally be a root widget in your App. Connect to the Store provided
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/// by this Widget using a [StoreConnector] or [StoreBuilder].
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class StoreProvider<S> extends InheritedWidget {
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final Store<S> _store;
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/// Create a [StoreProvider] by passing in the required [store] and [child]
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/// parameters.
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const StoreProvider({
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Key key,
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@required Store<S> store,
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@required Widget child,
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}) : assert(store != null),
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assert(child != null),
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_store = store,
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super(key: key, child: child);
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/// A method that can be called by descendant Widgets to retrieve the Store
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/// from the StoreProvider.
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///
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/// Important: When using this method, pass through complete type information
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/// or Flutter will be unable to find the correct StoreProvider!
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///
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/// ### Example
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///
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/// ```
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/// class MyWidget extends StatelessWidget {
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/// @override
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/// Widget build(BuildContext context) {
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/// final store = StoreProvider.of<int>(context);
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///
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/// return Text('${store.state}');
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/// }
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/// }
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/// ```
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static Store<S> of<S>(BuildContext context) {
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final type = _typeOf<StoreProvider<S>>();
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final provider =
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context.inheritFromWidgetOfExactType(type) as StoreProvider<S>;
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if (provider == null) throw StoreProviderError(type);
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return provider._store;
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}
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// Workaround to capture generics
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static Type _typeOf<T>() => T;
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@override
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bool updateShouldNotify(StoreProvider<S> oldWidget) =>
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_store != oldWidget._store;
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}
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/// Build a Widget using the [BuildContext] and [ViewModel]. The [ViewModel] is
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/// derived from the [Store] using a [StoreConverter].
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typedef ViewModelBuilder<ViewModel> = Widget Function(
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BuildContext context,
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ViewModel vm,
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);
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/// Convert the entire [Store] into a [ViewModel]. The [ViewModel] will be used
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/// to build a Widget using the [ViewModelBuilder].
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typedef StoreConverter<S, ViewModel> = ViewModel Function(
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Store<S> store,
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);
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/// A function that will be run when the [StoreConnector] is initialized (using
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/// the [State.initState] method). This can be useful for dispatching actions
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/// that fetch data for your Widget when it is first displayed.
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typedef OnInitCallback<S> = void Function(
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Store<S> store,
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);
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/// A function that will be run when the StoreConnector is removed from the
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/// Widget Tree.
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///
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/// It is run in the [State.dispose] method.
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///
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/// This can be useful for dispatching actions that remove stale data from
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/// your State tree.
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typedef OnDisposeCallback<S> = void Function(
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Store<S> store,
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);
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/// A test of whether or not your `converter` function should run in response
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/// to a State change. For advanced use only.
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///
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/// Some changes to the State of your application will mean your `converter`
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/// function can't produce a useful ViewModel. In these cases, such as when
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/// performing exit animations on data that has been removed from your Store,
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/// it can be best to ignore the State change while your animation completes.
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///
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/// To ignore a change, provide a function that returns true or false. If the
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/// returned value is true, the change will be ignored.
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///
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/// If you ignore a change, and the framework needs to rebuild the Widget, the
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/// `builder` function will be called with the latest `ViewModel` produced by
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/// your `converter` function.
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typedef IgnoreChangeTest<S> = bool Function(S state);
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/// A function that will be run on State change, before the build method.
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///
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/// This function is passed the `ViewModel`, and if `distinct` is `true`,
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/// it will only be called if the `ViewModel` changes.
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///
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/// This can be useful for imperative calls to things like Navigator,
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/// TabController, etc
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typedef OnWillChangeCallback<ViewModel> = void Function(ViewModel viewModel);
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/// A function that will be run on State change, after the build method.
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///
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/// This function is passed the `ViewModel`, and if `distinct` is `true`,
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/// it will only be called if the `ViewModel` changes.
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///
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/// This can be useful for running certain animations after the build is
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/// complete.
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///
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/// Note: Using a [BuildContext] inside this callback can cause problems if
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/// the callback performs navigation. For navigation purposes, please use
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/// an [OnWillChangeCallback].
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typedef OnDidChangeCallback<ViewModel> = void Function(ViewModel viewModel);
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/// A function that will be run after the Widget is built the first time.
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///
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/// This function is passed the initial `ViewModel` created by the `converter`
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/// function.
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///
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/// This can be useful for starting certain animations, such as showing
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/// Snackbars, after the Widget is built the first time.
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typedef OnInitialBuildCallback<ViewModel> = void Function(ViewModel viewModel);
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/// Build a widget based on the state of the [Store].
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///
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/// Before the [builder] is run, the [converter] will convert the store into a
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/// more specific `ViewModel` tailored to the Widget being built.
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///
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/// Every time the store changes, the Widget will be rebuilt. As a performance
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/// optimization, the Widget can be rebuilt only when the [ViewModel] changes.
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/// In order for this to work correctly, you must implement [==] and [hashCode]
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/// for the [ViewModel], and set the [distinct] option to true when creating
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/// your StoreConnector.
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class StoreConnector<S, ViewModel> extends StatelessWidget {
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/// Build a Widget using the [BuildContext] and [ViewModel]. The [ViewModel]
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/// is created by the [converter] function.
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final ViewModelBuilder<ViewModel> builder;
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/// Convert the [Store] into a [ViewModel]. The resulting [ViewModel] will be
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/// passed to the [builder] function.
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final StoreConverter<S, ViewModel> converter;
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/// As a performance optimization, the Widget can be rebuilt only when the
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/// [ViewModel] changes. In order for this to work correctly, you must
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/// implement [==] and [hashCode] for the [ViewModel], and set the [distinct]
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/// option to true when creating your StoreConnector.
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final bool distinct;
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/// A function that will be run when the StoreConnector is initially created.
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/// It is run in the [State.initState] method.
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///
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/// This can be useful for dispatching actions that fetch data for your Widget
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/// when it is first displayed.
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final OnInitCallback<S> onInit;
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/// A function that will be run when the StoreConnector is removed from the
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/// Widget Tree.
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///
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/// It is run in the [State.dispose] method.
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///
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/// This can be useful for dispatching actions that remove stale data from
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/// your State tree.
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final OnDisposeCallback<S> onDispose;
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/// Determines whether the Widget should be rebuilt when the Store emits an
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/// onChange event.
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final bool rebuildOnChange;
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/// A test of whether or not your [converter] function should run in response
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/// to a State change. For advanced use only.
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///
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/// Some changes to the State of your application will mean your [converter]
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/// function can't produce a useful ViewModel. In these cases, such as when
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/// performing exit animations on data that has been removed from your Store,
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/// it can be best to ignore the State change while your animation completes.
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///
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/// To ignore a change, provide a function that returns true or false. If the
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/// returned value is true, the change will be ignored.
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///
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/// If you ignore a change, and the framework needs to rebuild the Widget, the
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/// [builder] function will be called with the latest [ViewModel] produced by
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/// your [converter] function.
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final IgnoreChangeTest<S> ignoreChange;
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/// A function that will be run on State change, before the Widget is built.
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///
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/// This function is passed the `ViewModel`, and if `distinct` is `true`,
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/// it will only be called if the `ViewModel` changes.
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///
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/// This can be useful for imperative calls to things like Navigator,
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/// TabController, etc
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final OnWillChangeCallback<ViewModel> onWillChange;
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/// A function that will be run on State change, after the Widget is built.
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///
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/// This function is passed the `ViewModel`, and if `distinct` is `true`,
|
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/// it will only be called if the `ViewModel` changes.
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///
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/// This can be useful for running certain animations after the build is
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/// complete.
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///
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/// Note: Using a [BuildContext] inside this callback can cause problems if
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/// the callback performs navigation. For navigation purposes, please use
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/// [onWillChange].
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final OnDidChangeCallback<ViewModel> onDidChange;
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/// A function that will be run after the Widget is built the first time.
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///
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/// This function is passed the initial `ViewModel` created by the [converter]
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/// function.
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///
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/// This can be useful for starting certain animations, such as showing
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/// Snackbars, after the Widget is built the first time.
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final OnInitialBuildCallback<ViewModel> onInitialBuild;
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/// Create a [StoreConnector] by passing in the required [converter] and
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/// [builder] functions.
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///
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/// You can also specify a number of additional parameters that allow you to
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/// modify the behavior of the StoreConnector. Please see the documentation
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/// for each option for more info.
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StoreConnector({
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Key key,
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@required this.builder,
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@required this.converter,
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this.distinct = false,
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this.onInit,
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this.onDispose,
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this.rebuildOnChange = true,
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this.ignoreChange,
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this.onWillChange,
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this.onDidChange,
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this.onInitialBuild,
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}) : assert(builder != null),
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assert(converter != null),
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super(key: key);
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@override
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Widget build(BuildContext context) {
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return _StoreStreamListener<S, ViewModel>(
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store: StoreProvider.of<S>(context),
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builder: builder,
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converter: converter,
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distinct: distinct,
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onInit: onInit,
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onDispose: onDispose,
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rebuildOnChange: rebuildOnChange,
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ignoreChange: ignoreChange,
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onWillChange: onWillChange,
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onDidChange: onDidChange,
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onInitialBuild: onInitialBuild,
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);
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}
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}
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/// Build a Widget by passing the [Store] directly to the build function.
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///
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/// Generally, it's considered best practice to use the [StoreConnector] and to
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/// build a `ViewModel` specifically for your Widget rather than passing through
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/// the entire [Store], but this is provided for convenience when that isn't
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/// necessary.
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class StoreBuilder<S> extends StatelessWidget {
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static Store<S> _identity<S>(Store<S> store) => store;
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/// Builds a Widget using the [BuildContext] and your [Store].
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final ViewModelBuilder<Store<S>> builder;
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/// Indicates whether or not the Widget should rebuild when the [Store] emits
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/// an `onChange` event.
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final bool rebuildOnChange;
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/// A function that will be run when the StoreConnector is initially created.
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/// It is run in the [State.initState] method.
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///
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/// This can be useful for dispatching actions that fetch data for your Widget
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/// when it is first displayed.
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final OnInitCallback<S> onInit;
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/// A function that will be run when the StoreBuilder is removed from the
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/// Widget Tree.
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///
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/// It is run in the [State.dispose] method.
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///
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/// This can be useful for dispatching actions that remove stale data from
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/// your State tree.
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final OnDisposeCallback<S> onDispose;
|
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/// A function that will be run on State change, before the Widget is built.
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///
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/// This can be useful for imperative calls to things like Navigator,
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/// TabController, etc
|
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final OnWillChangeCallback<Store<S>> onWillChange;
|
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/// A function that will be run on State change, after the Widget is built.
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///
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/// This can be useful for running certain animations after the build is
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/// complete
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///
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/// Note: Using a [BuildContext] inside this callback can cause problems if
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/// the callback performs navigation. For navigation purposes, please use
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/// [onWillChange].
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final OnDidChangeCallback<Store<S>> onDidChange;
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/// A function that will be run after the Widget is built the first time.
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///
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/// This can be useful for starting certain animations, such as showing
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/// Snackbars, after the Widget is built the first time.
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final OnInitialBuildCallback<Store<S>> onInitialBuild;
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/// Create's a Widget based on the Store.
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StoreBuilder({
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Key key,
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@required this.builder,
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this.onInit,
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this.onDispose,
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this.rebuildOnChange = true,
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this.onWillChange,
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this.onDidChange,
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this.onInitialBuild,
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}) : assert(builder != null),
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super(key: key);
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@override
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Widget build(BuildContext context) {
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return StoreConnector<S, Store<S>>(
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builder: builder,
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converter: _identity,
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rebuildOnChange: rebuildOnChange,
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onInit: onInit,
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onDispose: onDispose,
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onWillChange: onWillChange,
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onDidChange: onDidChange,
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onInitialBuild: onInitialBuild,
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);
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}
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}
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/// Listens to the [Store] and calls [builder] whenever [store] changes.
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class _StoreStreamListener<S, ViewModel> extends StatefulWidget {
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final ViewModelBuilder<ViewModel> builder;
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final StoreConverter<S, ViewModel> converter;
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final Store<S> store;
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final bool rebuildOnChange;
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final bool distinct;
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final OnInitCallback<S> onInit;
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final OnDisposeCallback<S> onDispose;
|
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final IgnoreChangeTest<S> ignoreChange;
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final OnWillChangeCallback<ViewModel> onWillChange;
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final OnDidChangeCallback<ViewModel> onDidChange;
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final OnInitialBuildCallback<ViewModel> onInitialBuild;
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_StoreStreamListener({
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Key key,
|
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@required this.builder,
|
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@required this.store,
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@required this.converter,
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this.distinct = false,
|
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this.onInit,
|
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this.onDispose,
|
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this.rebuildOnChange = true,
|
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this.ignoreChange,
|
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this.onWillChange,
|
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this.onDidChange,
|
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this.onInitialBuild,
|
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}) : super(key: key);
|
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@override
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State<StatefulWidget> createState() {
|
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return _StoreStreamListenerState<S, ViewModel>();
|
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}
|
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}
|
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class _StoreStreamListenerState<S, ViewModel>
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extends State<_StoreStreamListener<S, ViewModel>> {
|
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Stream<ViewModel> stream;
|
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ViewModel latestValue;
|
||||
|
||||
@override
|
||||
void initState() {
|
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_init();
|
||||
|
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super.initState();
|
||||
}
|
||||
|
||||
@override
|
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void dispose() {
|
||||
if (widget.onDispose != null) {
|
||||
widget.onDispose(widget.store);
|
||||
}
|
||||
|
||||
super.dispose();
|
||||
}
|
||||
|
||||
@override
|
||||
void didUpdateWidget(_StoreStreamListener<S, ViewModel> oldWidget) {
|
||||
if (widget.store != oldWidget.store) {
|
||||
_init();
|
||||
}
|
||||
|
||||
super.didUpdateWidget(oldWidget);
|
||||
}
|
||||
|
||||
void _init() {
|
||||
if (widget.onInit != null) {
|
||||
widget.onInit(widget.store);
|
||||
}
|
||||
|
||||
latestValue = widget.converter(widget.store);
|
||||
|
||||
if (widget.onInitialBuild != null) {
|
||||
WidgetsBinding.instance.addPostFrameCallback((_) {
|
||||
widget.onInitialBuild(latestValue);
|
||||
});
|
||||
}
|
||||
|
||||
var _stream = widget.store.onChange;
|
||||
|
||||
if (widget.ignoreChange != null) {
|
||||
_stream = _stream.where((state) => !widget.ignoreChange(state));
|
||||
}
|
||||
|
||||
stream = _stream.map((_) => widget.converter(widget.store));
|
||||
|
||||
// Don't use `Stream.distinct` because it cannot capture the initial
|
||||
// ViewModel produced by the `converter`.
|
||||
if (widget.distinct) {
|
||||
stream = stream.where((vm) {
|
||||
final isDistinct = vm != latestValue;
|
||||
|
||||
return isDistinct;
|
||||
});
|
||||
}
|
||||
|
||||
// After each ViewModel is emitted from the Stream, we update the
|
||||
// latestValue. Important: This must be done after all other optional
|
||||
// transformations, such as ignoreChange.
|
||||
stream =
|
||||
stream.transform(StreamTransformer.fromHandlers(handleData: (vm, sink) {
|
||||
latestValue = vm;
|
||||
|
||||
if (widget.onWillChange != null) {
|
||||
widget.onWillChange(latestValue);
|
||||
}
|
||||
|
||||
if (widget.onDidChange != null) {
|
||||
WidgetsBinding.instance.addPostFrameCallback((_) {
|
||||
widget.onDidChange(latestValue);
|
||||
});
|
||||
}
|
||||
|
||||
sink.add(vm);
|
||||
}));
|
||||
}
|
||||
|
||||
@override
|
||||
Widget build(BuildContext context) {
|
||||
return widget.rebuildOnChange
|
||||
? StreamBuilder<ViewModel>(
|
||||
stream: stream,
|
||||
builder: (context, snapshot) => widget.builder(
|
||||
context,
|
||||
snapshot.hasData ? snapshot.data : latestValue,
|
||||
),
|
||||
)
|
||||
: widget.builder(context, latestValue);
|
||||
}
|
||||
}
|
||||
|
||||
/// If the StoreProvider.of method fails, this error will be thrown.
|
||||
///
|
||||
/// Often, when the `of` method fails, it is difficult to understand why since
|
||||
/// there can be multiple causes. This error explains those causes so the user
|
||||
/// can understand and fix the issue.
|
||||
class StoreProviderError extends Error {
|
||||
/// The type of the class the user tried to retrieve
|
||||
Type type;
|
||||
|
||||
/// Creates a StoreProviderError
|
||||
StoreProviderError(this.type);
|
||||
|
||||
@override
|
||||
String toString() {
|
||||
return '''Error: No $type found. To fix, please try:
|
||||
|
||||
* Wrapping your MaterialApp with the StoreProvider<State>,
|
||||
rather than an individual Route
|
||||
* Providing full type information to your Store<State>,
|
||||
StoreProvider<State> and StoreConnector<State, ViewModel>
|
||||
* Ensure you are using consistent and complete imports.
|
||||
E.g. always use `import 'package:my_app/app_state.dart';
|
||||
|
||||
If none of these solutions work, please file a bug at:
|
||||
https://github.com/brianegan/flutter_redux/issues/new
|
||||
''';
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user