flutter-state

问题 I am a beginner in Dart language development. I try to create a sample flutter application BLOC pattern inspired by this GitHub repo, but I got some error message related to the class inheritance. I am already familiar with the inheritance and superclass and subclass programming in the dot net C# language. But in the case of the dart, I need some advice. Here is my code: class UserRegBloc extends Bloc<UserRegEvent, UserRegState> { UserRepository userRepository; UserRegBloc({@required

问题 I am a beginner in Dart language development. I try to create a sample flutter application BLOC pattern inspired by this GitHub repo, but I got some error message related to the class inheritance. I am already familiar with the inheritance and superclass and subclass programming in the dot net C# language. But in the case of the dart, I need some advice. Here is my code: class UserRegBloc extends Bloc<UserRegEvent, UserRegState> { UserRepository userRepository; UserRegBloc({@required

问题 In my flutter app, I have a ConnectivityStatus widget which displays the current connection status of the app to my raspberry pi. In the initState of my widget, I subscribe to a timer to check the connection every 5 seconds and update the state accordingly, then unsubscribe upon disposal. The issue is, when multiple screens use the ConnectivityStatus widget, such as in a stack navigator setup, I now have two concurrent subscriptions as neither instance has disposed. This causes many redundant

来源： https://stackoverflow.com/questions/62735538/why-wont-any-changes-from-notifyparser-render-in-the-ui-using-provider-change

问题 I am learning state management in flutter and most of the time I encounter with words business logic ui logic and some time presentation logic , I searched it on the internet as people explain it in different languages, I couldn't get a better understanding, Could someone please show these three types of logic in the form of an example and explain it very clean and easy? 回答1: When we use a library, it is our responsibility and mission to separate it from critical parts of our code, which is

问题 Im trying to implement some basic state management in my Flutter app. Somewhere up the Widget tree I have a Provider for a User. Widgets further down can access the User using the Consumer User Widget. However one Widget (WidgetB in the code snipped below) is build using the Navigator.push() and cant access the User. Pushing the Button will throw the Error: Error: Could not find the correct Provider above this Consumer Widget floatingActionButton: FloatingActionButton( child: Icon(Icons.play)

问题 Im trying to implement some basic state management in my Flutter app. Somewhere up the Widget tree I have a Provider for a User. Widgets further down can access the User using the Consumer User Widget. However one Widget (WidgetB in the code snipped below) is build using the Navigator.push() and cant access the User. Pushing the Button will throw the Error: Error: Could not find the correct Provider above this Consumer Widget floatingActionButton: FloatingActionButton( child: Icon(Icons.play)

问题 I am trying to implement custom logout solution for my application, where no matter where user currently is, once the Logout button is clicked, app will navigate back to Login page . My idea was, that instead of listening on every component for state changes, I would have one single listener on a master component -> MyApp . For the sake of simplicity, I have stripped down items to bare minimum. Here is how my Profile class could look like: class Profile with ChangeNotifier { bool

问题 I am trying to implement custom logout solution for my application, where no matter where user currently is, once the Logout button is clicked, app will navigate back to Login page . My idea was, that instead of listening on every component for state changes, I would have one single listener on a master component -> MyApp . For the sake of simplicity, I have stripped down items to bare minimum. Here is how my Profile class could look like: class Profile with ChangeNotifier { bool

问题 I am trying to implement custom logout solution for my application, where no matter where user currently is, once the Logout button is clicked, app will navigate back to Login page . My idea was, that instead of listening on every component for state changes, I would have one single listener on a master component -> MyApp . For the sake of simplicity, I have stripped down items to bare minimum. Here is how my Profile class could look like: class Profile with ChangeNotifier { bool