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fix(flutter_bloc): Add dependency to bloc instance for BlocBuilder/BlocListener/BlocConsumer #2482

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Merged
merged 5 commits into from
May 27, 2021
Merged

fix(flutter_bloc): Add dependency to bloc instance for BlocBuilder/BlocListener/BlocConsumer #2482

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559f067
Add bloc context dependency for bloc widgets
pr0gramista May 27, 2021
b2302af
Make widgets depends on bloc instance change only
pr0gramista May 27, 2021
72ccb78
Add more tests for widgets bloc dependencies
pr0gramista May 27, 2021
dd5000a
refactor: minor updates
felangel May 27, 2021
01ecf30
Merge branch 'master' into bugfix/blocbuilder-dependency-change
felangel May 27, 2021
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11 changes: 11 additions & 0 deletions packages/flutter_bloc/lib/src/bloc_builder.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -132,6 +132,16 @@ class _BlocBuilderBaseState<B extends BlocBase<S>, S>
_state = _bloc.state;
}

@override
void didChangeDependencies() {
super.didChangeDependencies();
final bloc = widget.bloc ?? context.read<B>();
if (_bloc != bloc) {
_bloc = bloc;
_state = _bloc.state;
}
}

@override
void didUpdateWidget(BlocBuilderBase<B, S> oldWidget) {
super.didUpdateWidget(oldWidget);
Expand All @@ -145,6 +155,7 @@ class _BlocBuilderBaseState<B extends BlocBase<S>, S>

@override
Widget build(BuildContext context) {
if (widget.bloc == null) context.select<B, int>(identityHashCode);
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@felangel felangel May 27, 2021

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It's a very creative idea to solve the previous issue! I made one minor adjustment to use identityHashCode in case developers override hashCode manually.

return BlocListener<B, S>(
bloc: _bloc,
listenWhen: widget.buildWhen,
Expand Down
12 changes: 9 additions & 3 deletions packages/flutter_bloc/lib/src/bloc_consumer.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -115,13 +115,19 @@ class _BlocConsumerState<B extends BlocBase<S>, S>
super.didUpdateWidget(oldWidget);
final oldBloc = oldWidget.bloc ?? context.read<B>();
final currentBloc = widget.bloc ?? oldBloc;
if (oldBloc != currentBloc) {
_bloc = currentBloc;
}
if (oldBloc != currentBloc) _bloc = currentBloc;
}

@override
void didChangeDependencies() {
super.didChangeDependencies();
final bloc = widget.bloc ?? context.read<B>();
if (_bloc != bloc) _bloc = bloc;
}

@override
Widget build(BuildContext context) {
if (widget.bloc == null) context.select<B, int>(identityHashCode);
return BlocBuilder<B, S>(
bloc: _bloc,
builder: widget.builder,
Expand Down
19 changes: 18 additions & 1 deletion packages/flutter_bloc/lib/src/bloc_listener.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -151,6 +151,20 @@ class _BlocListenerBaseState<B extends BlocBase<S>, S>
_subscribe();
}

@override
void didChangeDependencies() {
super.didChangeDependencies();
final bloc = widget.bloc ?? context.read<B>();
if (_bloc != bloc) {
if (_subscription != null) {
_unsubscribe();
_bloc = bloc;
_previousState = _bloc.state;
}
_subscribe();
}
}

@override
void didUpdateWidget(BlocListenerBase<B, S> oldWidget) {
super.didUpdateWidget(oldWidget);
Expand All @@ -167,7 +181,10 @@ class _BlocListenerBaseState<B extends BlocBase<S>, S>
}

@override
Widget buildWithChild(BuildContext context, Widget? child) => child!;
Widget buildWithChild(BuildContext context, Widget? child) {
if (widget.bloc == null) context.select<B, int>(identityHashCode);
return child!;
}

@override
void dispose() {
Expand Down
44 changes: 44 additions & 0 deletions packages/flutter_bloc/test/bloc_builder_test.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -467,5 +467,49 @@ void main() {
await tester.pumpAndSettle();
expect(states, [0, 2, 2]);
});

testWidgets('rebuilds when provided bloc is changed', (tester) async {
final firstCounterCubit = CounterCubit();
final secondCounterCubit = CounterCubit()..emit(100);

await tester.pumpWidget(
Directionality(
textDirection: TextDirection.ltr,
child: BlocProvider.value(
value: firstCounterCubit,
child: BlocBuilder<CounterCubit, int>(
builder: (context, state) => Text('Count $state'),
),
),
),
);

expect(find.text('Count 0'), findsOneWidget);

firstCounterCubit.increment();
await tester.pumpAndSettle();
expect(find.text('Count 1'), findsOneWidget);
expect(find.text('Count 0'), findsNothing);

await tester.pumpWidget(
Directionality(
textDirection: TextDirection.ltr,
child: BlocProvider.value(
value: secondCounterCubit,
child: BlocBuilder<CounterCubit, int>(
builder: (context, state) => Text('Count $state'),
),
),
),
);

expect(find.text('Count 100'), findsOneWidget);
expect(find.text('Count 1'), findsNothing);

secondCounterCubit.increment();
await tester.pumpAndSettle();

expect(find.text('Count 101'), findsOneWidget);
});
});
}
53 changes: 53 additions & 0 deletions packages/flutter_bloc/test/bloc_consumer_test.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -345,5 +345,58 @@ void main() {
expect(listenWhenPreviousState, [2]);
expect(listenWhenCurrentState, [3]);
});

testWidgets(
'rebuilds and updates subscription '
'when provided bloc is changed', (tester) async {
final firstCounterCubit = CounterCubit();
final secondCounterCubit = CounterCubit()..emit(100);

final states = <int>[];
const expectedStates = [1, 101];

await tester.pumpWidget(
Directionality(
textDirection: TextDirection.ltr,
child: BlocProvider.value(
value: firstCounterCubit,
child: BlocConsumer<CounterCubit, int>(
listener: (_, state) => states.add(state),
builder: (context, state) => Text('Count $state'),
),
),
),
);

expect(find.text('Count 0'), findsOneWidget);

firstCounterCubit.increment();
await tester.pumpAndSettle();

expect(find.text('Count 1'), findsOneWidget);
expect(find.text('Count 0'), findsNothing);

await tester.pumpWidget(
Directionality(
textDirection: TextDirection.ltr,
child: BlocProvider.value(
value: secondCounterCubit,
child: BlocConsumer<CounterCubit, int>(
listener: (_, state) => states.add(state),
builder: (context, state) => Text('Count $state'),
),
),
),
);

expect(find.text('Count 100'), findsOneWidget);
expect(find.text('Count 1'), findsNothing);

secondCounterCubit.increment();
await tester.pumpAndSettle();

expect(find.text('Count 101'), findsOneWidget);
expect(states, expectedStates);
});
});
}
39 changes: 39 additions & 0 deletions packages/flutter_bloc/test/bloc_listener_test.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -439,5 +439,44 @@ void main() {

expect(states, expectedStates);
});

testWidgets(
'updates subscription '
'when provided bloc is changed', (tester) async {
final firstCounterCubit = CounterCubit();
final secondCounterCubit = CounterCubit()..emit(100);

final states = <int>[];
const expectedStates = [1, 101];

await tester.pumpWidget(
BlocProvider.value(
value: firstCounterCubit,
child: BlocListener<CounterCubit, int>(
listener: (_, state) => states.add(state),
child: const SizedBox(),
),
),
);

firstCounterCubit.increment();

await tester.pumpWidget(
BlocProvider.value(
value: secondCounterCubit,
child: BlocListener<CounterCubit, int>(
listener: (_, state) => states.add(state),
child: const SizedBox(),
),
),
);

secondCounterCubit.increment();
await tester.pump();
firstCounterCubit.increment();
await tester.pump();

expect(states, expectedStates);
});
});
}