feat(flutter_bloc): support listener current state #4405
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Allows setting a `startWithCurrentState` flag on `BlocListener` which
changes the behaviour to immediately call `listener` with the current
`state` of the bloc before calling again with subsequent emissions.
This allows the view layer to react to whatever the current state is
rather than only when it changes.
For example:
```dart
return BlocListener<AuthBloc, AuthState>(
// Ensure the listener is checked immediately on creation with
// current state in addition to future transitions.
// If the user is somehow routed to this page when not logged in
// they should be immediately kicked out, rather than only when
// they transition from logged in to logged out.
startWithCurrentState: true,
listener: (context, state) {
if(!state.isLoggedIn) {
context.router.replace(const UnauthenticatedRoute());
}
},
child: MyAuthenticatedPageContent(),
);
```
Closes felangel#4347
|
With this, I guess it will help us avoid writing boiler-plate ie checks in initialState (just to check on last emitted state !!) Then this indeed would be helpful +1 !! |
|
I like this idea! In few "rare" cases I also needed or had issues with this, since UI was constructed in some cases later than bloc emited the state and there wasnt better way to handle this to make it stable. So I think either this flag or alternatively having I think I like this flag a bit more. |
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Status
READY
Breaking Changes
NO
Description
Allows setting a
startWithCurrentStateflag onBlocListenerwhich changes the behaviour to immediately calllistenerwith the currentstateof the bloc before calling again with subsequent emissions.This allows the view layer to react to whatever the current state is rather than only when it changes.
For example:
Closes #4347
I don't love the name of the flag itself but I couldn't come up with anything better (naming things, amirite?).
Type of Change