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Description
Is there an existing issue for this?
- I have searched the existing issues and found no duplicates.
What plugin is this bug for?
Firebase UI Firestore
What platform(s) does this bug affect?
Web
List of dependencies used.
flutter pub deps -s list
Our dependency list is very long, and contains private packages, therefore I only include the relevant firebase packages here:
- firebase_core 2.21.0
- firebase_core_platform_interface ^5.0.0
- firebase_core_web ^2.8.1
- flutter any
- meta ^1.8.0
- firebase_auth 4.12.1
- firebase_auth_platform_interface ^7.0.3
- firebase_auth_web ^5.8.6
- firebase_core ^2.21.0
- firebase_core_platform_interface ^5.0.0
- flutter any
- meta ^1.8.0
- firebase_messaging 14.7.3
- firebase_core ^2.21.0
- firebase_core_platform_interface ^5.0.0
- firebase_messaging_platform_interface ^4.5.12
- firebase_messaging_web ^3.5.12
- flutter any
- meta ^1.8.0
- firebase_crashlytics 3.4.3
- firebase_core ^2.21.0
- firebase_core_platform_interface ^5.0.0
- firebase_crashlytics_platform_interface ^3.6.11
- flutter any
- stack_trace ^1.10.0
- cloud_firestore 4.12.2
- cloud_firestore_platform_interface ^6.0.3
- cloud_firestore_web ^3.8.3
- collection ^1.0.0
- firebase_core ^2.21.0
- firebase_core_platform_interface ^5.0.0
- flutter any
- meta ^1.8.0
- firebase_ui_firestore ^1.5.7
Steps to reproduce
- Do not enable Persistance on Web (default is -- as far as I know -- a small memory cache)
- Have
.snapshots()-Stream on a single firestore document (lets call it docA ); Render this document e.g. with a StreamBuilder. - Next to that use the
FirestoreListViewto render a list of documents (including docA ). The database should contain enough documents, to allow for multiple pages. - Scroll down the
FirestoreListViewto trigger the "fetch more" functionality. - Now the FirestoreListView will render a list only containing docA for a very short amount of time and then render the full list. This results in the scroll position beeing lost and the whole list apparently jumping to the top.
Expected Behavior
I would expect the List not jumping. And thereby, as far as I understood the bug, I would expect the list not rendering a single cached item inbetween list fetches. I would also be fine with disabling any caching behavior on web, if there's a way to do that.
Actual Behavior
(see steps to reproduce)
Additional Information
I briefly looked into the FirestoreListView code (packages/firebase_ui_firestore/lib/src/query_builder.dart) . If I'm not mistaken, the problems lies in the query.snapshots().listen()-Callback in lines 176 et seq. Here any data is "rendered", as long as its smaller then expectedDocsCount, which of course includes the one item eagerly returned by the cache.