我正在尝试使用bloc模式来管理来自API的数据并在我的小部件中显示它们。我能够从API获取数据并处理它并显示它,但我使用的是底部导航栏,当我更改选项卡并转到我之前的选项卡时,它会返回以下错误:
未处理的异常:错误状态:调用close后无法添加新事件。
我知道这是因为我正在关闭流然后尝试添加它,但我不知道如何解决它,因为不处理publishsubject
将导致memory leak
。这是我的Ui代码:
class CategoryPage extends StatefulWidget {
@override
_CategoryPageState createState() => _CategoryPageState();
}
class _CategoryPageState extends State<CategoryPage> {
@override
void initState() {
serviceBloc.getAllServices();
super.initState();
}
@override
void dispose() {
serviceBloc.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return StreamBuilder(
stream: serviceBloc.allServices,
builder: (context, AsyncSnapshot<ServiceModel> snapshot) {
if (snapshot.hasData) {
return _homeBody(context, snapshot);
}
if (snapshot.hasError) {
return Center(
child: Text('Failed to load data'),
);
}
return CircularProgressIndicator();
},
);
}
}
_homeBody(BuildContext context, AsyncSnapshot<ServiceModel> snapshot) {
return Stack(
Padding(
padding: EdgeInsets.only(top: screenAwareSize(400, context)),
child: _buildCategories(context, snapshot))
],
);
}
_buildCategories(BuildContext context, AsyncSnapshot<ServiceModel> snapshot) {
return Padding(
padding: EdgeInsets.symmetric(vertical: 20),
child: GridView.builder(
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 3, crossAxisSpacing: 3.0),
itemCount: snapshot.data.result.length,
itemBuilder: (BuildContext context, int index) {
return InkWell(
child: CategoryWidget(
title: snapshot.data.result[index].name,
icon: Icons.phone_iphone,
),
onTap: () {},
);
},
),
);
}
这是我的集团代码:
class ServiceBloc extends MainBloc {
final _repo = new Repo();
final PublishSubject<ServiceModel> _serviceController =
new PublishSubject<ServiceModel>();
Observable<ServiceModel> get allServices => _serviceController.stream;
getAllServices() async {
appIsLoading();
ServiceModel movieItem = await _repo.getAllServices();
_serviceController.sink.add(movieItem);
appIsNotLoading();
}
void dispose() {
_serviceController.close();
}
}
ServiceBloc serviceBloc = new ServiceBloc();
我没有包含repo和API代码,因为它不在此错误的主题中。
如果错误实际上是由您发布的代码引起的,我只需添加一个检查以确保在调用dispose()
后没有添加新事件。
class ServiceBloc extends MainBloc {
final _repo = new Repo();
final PublishSubject<ServiceModel> _serviceController =
new PublishSubject<ServiceModel>();
Observable<ServiceModel> get allServices => _serviceController.stream;
getAllServices() async {
// do nothing if already disposed
if(_isDisposed) {
return;
}
appIsLoading();
ServiceModel movieItem = await _repo.getAllServices();
_serviceController.sink.add(movieItem);
appIsNotLoading();
}
bool _isDisposed = false;
void dispose() {
_serviceController.close();
_isDisposed = true;
}
}
ServiceBloc serviceBloc = new ServiceBloc();