🐛 [firebase_ui_firestore] Enable showing a progress indicator when fetching more pages

[rorystephenson]

Is there an existing issue for this?

• [X] 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?

Android, iOS, Web, macOS, Linux, Windows

List of dependencies used.

flutter pub deps -s list

Dart SDK 3.1.3
Flutter SDK 3.13.6
firebase_ui_firestore 1.5.11
dependencies:

• cloud_firestore 4.9.2
• cloud_firestore_platform_interface ^5.16.1
• cloud_firestore_web ^3.7.1
• collection ^1.0.0
• firebase_core ^2.16.0
• firebase_core_platform_interface ^4.8.0
• flutter any
• meta ^1.8.0
• firebase_ui_localizations 1.6.1
  • flutter any
  • flutter_localizations any
  • path ^1.8.2
• flutter 0.0.0
  • characters 1.3.0
  • collection 1.17.2
  • material_color_utilities 0.5.0
  • meta 1.9.1
  • vector_math 2.1.4
  • web 0.1.4-beta
  • sky_engine any

dev dependencies:

• flutter_test 0.0.0
  • flutter any
  • test_api 0.6.0
  • matcher 0.12.16
  • path 1.8.3
  • fake_async 1.3.1
  • clock 1.1.1
  • stack_trace 1.11.0
  • vector_math 2.1.4
  • async 2.11.0
  • boolean_selector 2.1.1
  • characters 1.3.0
  • collection 1.17.2
  • material_color_utilities 0.5.0
  • meta 1.9.1
  • source_span 1.10.0
  • stream_channel 2.1.1
  • string_scanner 1.2.0
  • term_glyph 1.2.1
  • web 0.1.4-beta
• flutter_lints 2.0.3
  • lints ^2.0.0
• mockito 5.4.2
  • analyzer >=5.11.0 <6.0.0
  • build >=1.3.0 <3.0.0
  • code_builder ^4.5.0
  • collection ^1.15.0
  • dart_style >=1.3.6 <3.0.0
  • matcher ^0.12.15
  • meta ^1.3.0
  • path ^1.8.0
  • source_gen >=0.9.6 <2.0.0
  • test_api >=0.2.1 <0.7.0

transitive dependencies:

• _fe_analyzer_shared 61.0.0
  • meta ^1.0.2
• _flutterfire_internals 1.3.6
  • collection ^1.0.0
  • firebase_core ^2.16.0
  • firebase_core_platform_interface ^4.8.0
  • flutter any
  • meta ^1.8.0
• analyzer 5.13.0
  • _fe_analyzer_shared ^61.0.0
  • collection ^1.17.0
  • convert ^3.0.0
  • crypto ^3.0.0
  • glob ^2.0.0
  • meta ^1.7.0
  • package_config ^2.0.0
  • path ^1.8.0
  • pub_semver ^2.0.0
  • source_span ^1.8.0
  • watcher ^1.0.0
  • yaml ^3.0.0
• args 2.4.2
• async 2.11.0
  • collection ^1.15.0
  • meta ^1.1.7
• boolean_selector 2.1.1
  • source_span ^1.8.0
  • string_scanner ^1.1.0
• build 2.4.1
  • analyzer >=1.5.0 <7.0.0
  • async ^2.5.0
  • convert ^3.0.0
  • crypto ^3.0.0
  • glob ^2.0.0
  • logging ^1.0.0
  • meta ^1.3.0
  • package_config ^2.1.0
  • path ^1.8.0
• built_collection 5.1.1
• built_value 8.6.3
  • built_collection ^5.0.0
  • collection ^1.15.0
  • fixnum ^1.0.0
  • meta ^1.3.0
• characters 1.3.0
• clock 1.1.1
• cloud_firestore_platform_interface 5.16.1
  • _flutterfire_internals ^1.3.6
  • collection ^1.15.0
  • firebase_core ^2.16.0
  • flutter any
  • meta ^1.8.0
  • plugin_platform_interface ^2.1.3
• cloud_firestore_web 3.7.1
  • _flutterfire_internals ^1.3.6
  • cloud_firestore_platform_interface ^5.16.1
  • collection ^1.0.0
  • firebase_core ^2.16.0
  • firebase_core_web ^2.8.0
  • flutter any
  • flutter_web_plugins any
  • js ^0.6.3
• code_builder 4.7.0
  • built_collection ^5.0.0
  • built_value ^8.0.0
  • collection ^1.15.0
  • matcher ^0.12.10
  • meta ^1.3.0
• collection 1.17.2
• convert 3.1.1
  • typed_data ^1.3.0
• crypto 3.0.3
  • typed_data ^1.3.0
• dart_style 2.3.2
  • analyzer >=5.12.0 <7.0.0
  • args >=1.0.0 <3.0.0
  • path ^1.0.0
  • pub_semver >=1.4.4 <3.0.0
  • source_span ^1.4.0
• fake_async 1.3.1
  • clock ^1.1.0
  • collection ^1.15.0
• file 7.0.0
  • meta ^1.9.1
  • path ^1.8.3
• firebase_core 2.16.0
  • firebase_core_platform_interface ^4.8.0
  • firebase_core_web ^2.8.0
  • flutter any
  • meta ^1.8.0
• firebase_core_platform_interface 4.8.0
  • collection ^1.0.0
  • flutter any
  • flutter_test any
  • meta ^1.8.0
  • plugin_platform_interface ^2.1.3
• firebase_core_web 2.8.0
  • firebase_core_platform_interface ^4.8.0
  • flutter any
  • flutter_web_plugins any
  • js ^0.6.3
  • meta ^1.8.0
• fixnum 1.1.0
• flutter_localizations 0.0.0
  • flutter any
  • intl 0.18.1
  • characters 1.3.0
  • clock 1.1.1
  • collection 1.17.2
  • material_color_utilities 0.5.0
  • meta 1.9.1
  • path 1.8.3
  • vector_math 2.1.4
  • web 0.1.4-beta
• flutter_web_plugins 0.0.0
  • flutter any
  • characters 1.3.0
  • collection 1.17.2
  • material_color_utilities 0.5.0
  • meta 1.9.1
  • vector_math 2.1.4
  • web 0.1.4-beta
• glob 2.1.2
  • async ^2.5.0
  • collection ^1.15.0
  • file >=6.1.3 <8.0.0
  • path ^1.8.0
  • string_scanner ^1.1.0
• intl 0.18.1
  • clock ^1.1.0
  • meta ^1.0.2
  • path ^1.8.0
• js 0.6.7
  • meta ^1.7.0
• lints 2.1.1
• logging 1.2.0
• matcher 0.12.16
  • async ^2.10.0
  • meta ^1.8.0
  • stack_trace ^1.10.0
  • term_glyph ^1.2.0
  • test_api >=0.5.0 <0.7.0
• material_color_utilities 0.5.0
  • collection ^1.15.0
• meta 1.9.1
• package_config 2.1.0
  • path ^1.8.0
• path 1.8.3
• plugin_platform_interface 2.1.6
  • meta ^1.3.0
• pub_semver 2.1.4
  • collection ^1.15.0
  • meta ^1.3.0
• sky_engine 0.0.99
• source_gen 1.4.0
  • analyzer >=5.2.0 <7.0.0
  • async ^2.5.0
  • build ^2.1.0
  • dart_style ^2.0.0
  • glob ^2.0.0
  • path ^1.8.0
  • source_span ^1.8.0
  • yaml ^3.0.0
• source_span 1.10.0
  • collection ^1.15.0
  • path ^1.8.0
  • term_glyph ^1.2.0
• stack_trace 1.11.0
  • path ^1.8.0
• stream_channel 2.1.1
  • async ^2.5.0
• string_scanner 1.2.0
  • source_span ^1.8.0
• term_glyph 1.2.1
• test_api 0.6.0
  • async ^2.5.0
  • boolean_selector ^2.1.0
  • collection ^1.15.0
  • meta ^1.3.0
  • source_span ^1.8.0
  • stack_trace ^1.10.0
  • stream_channel ^2.1.0
  • string_scanner ^1.1.0
  • term_glyph ^1.2.0
• typed_data 1.3.2
  • collection ^1.15.0
• vector_math 2.1.4
• watcher 1.1.0
  • async ^2.5.0
  • path ^1.8.0
• web 0.1.4-beta
• yaml 3.1.2
  • collection ^1.15.0
  • source_span ^1.8.0
  • string_scanner ^1.1.0

Steps to reproduce

1. Run the example app with two minor changes: set pageSize to a small number like 2 and add a loadingBuilder with a debugPrint statement and visible child like a red Container with 100 height.
2. Wait for the initial load which populates the visible elements.
3. Scroll to the bottom fast.

Example changes:

diff --git a/packages/firebase_ui_firestore/example/lib/main.dart b/packages/firebase_ui_firestore/example/lib/main.dart
index 50fe4ed..4bf44e8 100644
--- a/packages/firebase_ui_firestore/example/lib/main.dart
+++ b/packages/firebase_ui_firestore/example/lib/main.dart
@@ -34,7 +34,15 @@ class FirebaseUIFirestoreExample extends StatelessWidget {
         appBar: AppBar(title: const Text('Contacts')),
         body: FirestoreListView<User>(
           query: collection,
+          pageSize: 2,
           padding: const EdgeInsets.all(8.0),
+          loadingBuilder: (context) {
+            debugPrint('SHOWING LOADING INDICATOR');
+            return Container(
+              height: 100,
+              color: Colors.red,
+            );
+          },
           itemBuilder: (context, snapshot) {
             final user = snapshot.data();
             return Column(

Expected Behavior

1. During the initial load the load indicator whilst the visible elements are loading. ✅
2. When scrolling to the bottom fast, the loading indicator should be visible at the end of the list whilst we are fetching more documents ❌ .

Actual Behavior

During the initial load the loading indicator shows correctly, when fetching subsequent pages it is never shown.

Additional Information

No response