Add possibly to access store from initState (#161)

* feat: add the possibility to access to store from initState

by using ancestorInheritedElementForWidgetOfExactType

* Add test

* fix: fix test

* doc: add listen git documentation

Author: Taym95

lib/flutter_redux.dart

@@ -41,10 +41,43 @@ class StoreProvider<S> extends InheritedWidget {
   ///   }
   /// }
   /// ```
-  static Store<S> of<S>(BuildContext context) {
+
+  /// if you need to use the [Store] from an initState function
+  /// set the [listen] option to false
+  /// 
+  /// ### Example
+  /// 
+  /// ```
+  /// class MyWidget extends StatefulWidget {
+  ///   static GlobalKey<_MyWidgetState> captorKey = GlobalKey<_MyWidgetState>();
+  ///
+  ///   MyWidget() : super(key: captorKey);
+  ///
+  ///   _MyWidgetState createState() => _MyWidgetState();
+  /// }
+  ///
+  /// class _MyWidgetState extends State<MyWidget> {
+  ///   Store<String> store;
+  ///
+  ///   @override
+  ///   void initState() {
+  ///     super.initState();
+  ///     store = StoreProvider.of<String>(context, listen: false);
+  ///   }
+  ///
+  ///   @override
+  ///  Widget build(BuildContext context) {
+  ///     return Container();
+  ///   }
+  /// }
+  /// ```
+  static Store<S> of<S>(BuildContext context, {bool listen = true}) {
     final type = _typeOf<StoreProvider<S>>();
-    final provider =
-        context.inheritFromWidgetOfExactType(type) as StoreProvider<S>;
+    final provider = (listen
+        ? context.inheritFromWidgetOfExactType(type)
+        : context
+            .ancestorInheritedElementForWidgetOfExactType(type)
+            ?.widget) as StoreProvider<S>;
 
     if (provider == null) throw StoreProviderError(type);
 

test/flutter_redux_test.dart

@@ -164,6 +164,23 @@ void main() {
       expect(numBuilds, 2);
     });
 
+    testWidgets('can access store from initState', (WidgetTester tester) async {
+      final store = Store<String>(
+        identityReducer,
+        initialState: 'I',
+      );
+      final widget = StoreProvider<String>(
+        store: store,
+        child: StoreCaptorStateful(),
+      );
+
+      // Build the widget with the initial state
+      await tester.pumpWidget(widget);
+
+      // Check whether the store it captures is the same as the store created at the beginning
+      expect(StoreCaptorStateful.captorKey.currentState.store, store);
+    });
+
     testWidgets('does not rebuild if rebuildOnChange is set to false',
         (WidgetTester tester) async {
       var numBuilds = 0;
@@ -665,6 +682,30 @@ class StoreCaptor<S> extends StatelessWidget {
   }
 }
 
+class StoreCaptorStateful extends StatefulWidget {
+  static GlobalKey<_StoreCaptorStatefulState> captorKey =
+      GlobalKey<_StoreCaptorStatefulState>();
+
+  StoreCaptorStateful() : super(key: captorKey);
+
+  _StoreCaptorStatefulState createState() => _StoreCaptorStatefulState();
+}
+
+class _StoreCaptorStatefulState extends State<StoreCaptorStateful> {
+  Store<String> store;
+
+  @override
+  void initState() {
+    super.initState();
+    store = StoreProvider.of<String>(context, listen: false);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Container();
+  }
+}
+
 String identityReducer(String state, dynamic action) {
   return action.toString();
 }