{beam_location}: [add] onUpdate

- closes #507
slovnicki · Jun 10, 2022 · 88c8537 · 88c8537
1 parent cc2c265
commit 88c8537
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Showing 3 changed files with 23 additions and 10 deletions.
diff --git a/examples/books_bloc/lib/main.dart b/examples/books_bloc/lib/main.dart
@@ -14,9 +14,7 @@ class HomeScreen extends StatelessWidget {
       ),
       body: Center(
         child: ElevatedButton(
-          onPressed: () => context
-            ..read<BooksBloc>().add(LoadBooks())
-            ..beamToNamed('/books'),
+          onPressed: () => context.beamToNamed('/books'),
           child: Text('See books'),
         ),
       ),
@@ -40,9 +38,7 @@ class BooksScreen extends StatelessWidget {
                     (book) => ListTile(
                       title: Text(book.title),
                       subtitle: Text(book.author),
-                      onTap: () => context
-                        ..read<BooksBloc>().add(LoadBook(book.id))
-                        ..beamToNamed('/books/${book.id}'),
+                      onTap: () => context.beamToNamed('/books/${book.id}'),
                     ),
                   )
                   .toList(),
@@ -83,13 +79,22 @@ class BookDetailsScreen extends StatelessWidget {
 
 // LOCATIONS
 class BooksLocation extends BeamLocation<BeamState> {
-  BooksLocation() : super() {
-    addListener(_listener);
+  late BooksBloc _booksBloc;
+
+  @override
+  void initState() {
+    super.initState();
+    _booksBloc = BooksBloc();
   }
 
-  final BooksBloc _booksBloc = BooksBloc();
+  @override
+  void disposeState() {
+    _booksBloc.close();
+    super.disposeState();
+  }
 
-  void _listener() {
+  @override
+  void onUpdate() {
     if (state.pathPatternSegments.isEmpty) return;
 
     final bookId = state.pathParameters.containsKey('bookId')

diff --git a/package/lib/src/beam_location.dart b/package/lib/src/beam_location.dart
@@ -194,6 +194,12 @@ abstract class BeamLocation<T extends RouteInformationSerializable>
     state = createState(routeInformation);
   }
 
+  /// Called after [initState] and on each [update],
+  /// i.e. whenever we navigate with this [BeamLocation].
+  ///
+  /// Useful for delegating some tasks that depend on navigation.
+  void onUpdate() {}
+
   /// How to release any resources used by [state].
   ///
   /// Override this if
@@ -248,6 +254,7 @@ abstract class BeamLocation<T extends RouteInformationSerializable>
         );
       }
     }
+    onUpdate();
     if (rebuild) {
       notifyListeners();
     }

diff --git a/package/lib/src/beamer_delegate.dart b/package/lib/src/beamer_delegate.dart
@@ -846,6 +846,7 @@ class BeamerDelegate extends RouterDelegate<RouteInformation>
 
   void _initBeamLocation(BeamLocation beamLocation) {
     beamLocation.initState();
+    beamLocation.onUpdate();
     beamLocation.addListener(_updateFromCurrentBeamLocation);
   }