问题描述
在下面的示例中，我们可以看到在这个有状态的小部件中新创建了一个区块
authenticationBloc = AuthenticationBloc(userRepository: userRepository);
class App extends StatefulWidget {
final UserRepository userRepository;
App({Key key,@required this.userRepository}) : super(key: key);
@override
State<App> createState() => _AppState();
}
class _AppState extends State<App> {
AuthenticationBloc authenticationBloc;
UserRepository get userRepository => widget.userRepository;
@override
void initState() {
authenticationBloc = AuthenticationBloc(userRepository: userRepository); <------
authenticationBloc.dispatch(AppStarted());
super.initState();
}
@override
void dispose() { <---------
authenticationBloc.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return BlocProvider<AuthenticationBloc>(
bloc: authenticationBloc,child: MaterialApp(
home: BlocBuilder<AuthenticationEvent,AuthenticationState>(
bloc: authenticationBloc,builder: (BuildContext context,AuthenticationState state) {
if (state is AuthenticationUninitialized) {
return SplashPage();
}
if (state is AuthenticationAuthenticated) {
return HomePage();
}
if (state is AuthenticationUnauthenticated) {
return LoginPage(userRepository: userRepository);
}
if (state is AuthenticationLoading) {
return LoadingIndicator();
}
},),);
}
}
但是随后它也被放置在相同的有状态小部件中
@override
void dispose() {
authenticationBloc.dispose(); <-----
super.dispose();
}
现在在子小部件HomePage()中，如果authenticationBloc statefulwidget中已经放置了BlocProvider.of<AuthenticationBloc>(context)，我怎么仍能使用App访问authenticationBloc.dispose();？
function myFunction(){
$dbinfo = get_db_info();
$users = $dbinfo->get_results("
SELECT
Email,ID,Name,Address
FROM Database_table
WHERE ID = 5
");
if($users) {
$output = '';
foreach($users as $user) {
$ID = $user->ID;
$dname = $user->Name;
$email = $user->Email;
$address = $user->Address;
}else{
$output .= 'No user found';
}
}//endif
return $output;
}
是否正在关闭水槽？还是我理解这个错误？
解决方法
当应从树中永久删除_AppState且永远不会再构建State对象时，将调用dispose方法。
因此，由于仍在构建子小部件，因此尚未运行您的dispose方法。