Improve course units loading behavior

uni/lib/view/common_widgets/pages_layouts/general/general.dart

@@ -4,6 +4,7 @@ import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:flutter_svg/flutter_svg.dart';
 import 'package:provider/provider.dart';
+import 'package:sentry_flutter/sentry_flutter.dart';
 import 'package:uni/model/providers/startup/profile_provider.dart';
 import 'package:uni/model/providers/startup/session_provider.dart';
 import 'package:uni/utils/drawer_items.dart';
@@ -13,30 +14,64 @@ import 'package:uni/view/profile/profile.dart';
 /// Page with a hamburger menu and the user profile picture
 abstract class GeneralPageViewState<T extends StatefulWidget> extends State<T> {
   final double borderMargin = 18;
+  bool _loadedOnce = false;
+  bool _loading = true;
 
   Future<void> onRefresh(BuildContext context);
 
   Future<void> onLoad(BuildContext context) async {}
 
   @override
   Widget build(BuildContext context) {
-    WidgetsBinding.instance.addPostFrameCallback((_) => onLoad(context));
-    return getScaffold(context, getBody(context));
+    WidgetsBinding.instance.addPostFrameCallback((_) async {
+      if (_loadedOnce) {
+        return;
+      }
+      _loadedOnce = true;
+      setState(() {
+        _loading = true;
+      });
+
+      try {
+        await onLoad(context);
+      } catch (e, stackTrace) {
+        await Sentry.captureException(e, stackTrace: stackTrace);
+      }
+
+      setState(() {
+        _loading = false;
+      });
+    });
+
+    return getScaffold(
+      context,
+      _loading
+          ? const Flex(
+        direction: Axis.vertical,
+        children: [
+          Expanded(
+            child: Center(
+              child: CircularProgressIndicator(),
+            ),
+          )
+        ],
+      )
+          : getBody(context),
+    );
   }
 
   Widget getBody(BuildContext context) {
     return Container();
   }
 
-  Future<DecorationImage> buildProfileDecorationImage(
-    BuildContext context, {
+  Future<DecorationImage> buildProfileDecorationImage(BuildContext context, {
     bool forceRetrieval = false,
   }) async {
     final sessionProvider =
-        Provider.of<SessionProvider>(context, listen: false);
+    Provider.of<SessionProvider>(context, listen: false);
     await sessionProvider.ensureInitializedFromStorage();
     final profilePictureFile =
-        await ProfileProvider.fetchOrGetCachedProfilePicture(
+    await ProfileProvider.fetchOrGetCachedProfilePicture(
       sessionProvider.session,
       forceRetrieval: forceRetrieval,
     );
@@ -49,20 +84,23 @@ abstract class GeneralPageViewState<T extends StatefulWidget> extends State<T> {
   DecorationImage getProfileDecorationImage(File? profilePicture) {
     const fallbackPicture = AssetImage('assets/images/profile_placeholder.png');
     final image =
-        profilePicture == null ? fallbackPicture : FileImage(profilePicture);
+    profilePicture == null ? fallbackPicture : FileImage(profilePicture);
 
     final result =
-        DecorationImage(fit: BoxFit.cover, image: image as ImageProvider);
+    DecorationImage(fit: BoxFit.cover, image: image as ImageProvider);
     return result;
   }
 
   Widget refreshState(BuildContext context, Widget child) {
     return RefreshIndicator(
       key: GlobalKey<RefreshIndicatorState>(),
-      onRefresh: () => ProfileProvider.fetchOrGetCachedProfilePicture(
-        Provider.of<SessionProvider>(context, listen: false).session,
-        forceRetrieval: true,
-      ).then((value) => onRefresh(context)),
+      onRefresh: () =>
+          ProfileProvider.fetchOrGetCachedProfilePicture(
+            Provider
+                .of<SessionProvider>(context, listen: false)
+                .session,
+            forceRetrieval: true,
+          ).then((value) => onRefresh(context)),
       child: child,
     );
   }
@@ -86,21 +124,30 @@ abstract class GeneralPageViewState<T extends StatefulWidget> extends State<T> {
       bottom: PreferredSize(
         preferredSize: Size.zero,
         child: Container(
-          color: Theme.of(context).dividerColor,
+          color: Theme
+              .of(context)
+              .dividerColor,
           margin: EdgeInsets.only(left: borderMargin, right: borderMargin),
           height: 1.5,
         ),
       ),
       elevation: 0,
-      iconTheme: Theme.of(context).iconTheme,
-      backgroundColor: Theme.of(context).scaffoldBackgroundColor,
+      iconTheme: Theme
+          .of(context)
+          .iconTheme,
+      backgroundColor: Theme
+          .of(context)
+          .scaffoldBackgroundColor,
       titleSpacing: 0,
       title: ButtonTheme(
         materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
         shape: const RoundedRectangleBorder(),
         child: TextButton(
           onPressed: () {
-            final currentRouteName = ModalRoute.of(context)!.settings.name;
+            final currentRouteName = ModalRoute
+                .of(context)!
+                .settings
+                .name;
             if (currentRouteName != DrawerItem.navPersonalArea.title) {
               Navigator.pushNamed(
                 context,
@@ -110,7 +157,9 @@ abstract class GeneralPageViewState<T extends StatefulWidget> extends State<T> {
           },
           child: SvgPicture.asset(
             colorFilter: ColorFilter.mode(
-              Theme.of(context).primaryColor,
+              Theme
+                  .of(context)
+                  .primaryColor,
               BlendMode.srcIn,
             ),
             'assets/images/logo_dark.svg',
@@ -128,12 +177,11 @@ abstract class GeneralPageViewState<T extends StatefulWidget> extends State<T> {
   Widget getTopRightButton(BuildContext context) {
     return FutureBuilder(
       future: buildProfileDecorationImage(context),
-      builder: (
-        BuildContext context,
-        AsyncSnapshot<DecorationImage> decorationImage,
-      ) {
+      builder: (BuildContext context,
+          AsyncSnapshot<DecorationImage> decorationImage,) {
         return TextButton(
-          onPressed: () => {
+          onPressed: () =>
+          {
             Navigator.push(
               context,
               MaterialPageRoute<ProfilePageView>(

uni/lib/view/course_unit_info/course_unit_info.dart

@@ -6,13 +6,12 @@ import 'package:uni/model/providers/lazy/course_units_info_provider.dart';
 import 'package:uni/model/providers/startup/session_provider.dart';
 import 'package:uni/view/common_widgets/page_title.dart';
 import 'package:uni/view/common_widgets/pages_layouts/secondary/secondary.dart';
-import 'package:uni/view/common_widgets/request_dependent_widget_builder.dart';
 import 'package:uni/view/course_unit_info/widgets/course_unit_classes.dart';
 import 'package:uni/view/course_unit_info/widgets/course_unit_sheet.dart';
-import 'package:uni/view/lazy_consumer.dart';
 
 class CourseUnitDetailPageView extends StatefulWidget {
   const CourseUnitDetailPageView(this.courseUnit, {super.key});
+
   final CourseUnit courseUnit;
 
   @override
@@ -91,50 +90,36 @@ class CourseUnitDetailPageViewState
   }
 
   Widget _courseUnitSheetView(BuildContext context) {
-    return LazyConsumer<CourseUnitsInfoProvider>(
-      builder: (context, courseUnitsInfoProvider) {
-        return RequestDependentWidgetBuilder(
-          onNullContent: Center(
-            child: Text(
-              S.of(context).no_info,
-              textAlign: TextAlign.center,
-            ),
-          ),
-          status: courseUnitsInfoProvider.status,
-          builder: () => CourseUnitSheetView(
-            courseUnitsInfoProvider.courseUnitsSheets[widget.courseUnit]!,
-          ),
-          hasContentPredicate:
-              courseUnitsInfoProvider.courseUnitsSheets[widget.courseUnit] !=
-                      null &&
-                  courseUnitsInfoProvider.courseUnitsSheets[widget.courseUnit]!
-                      .sections.isNotEmpty,
-        );
-      },
-    );
+    final sheet = context
+        .read<CourseUnitsInfoProvider>()
+        .courseUnitsSheets[widget.courseUnit];
+
+    if (sheet == null || sheet.sections.isEmpty) {
+      return Center(
+        child: Text(
+          S.of(context).no_info,
+          textAlign: TextAlign.center,
+        ),
+      );
+    }
+
+    return CourseUnitSheetView(sheet);
   }
 
   Widget _courseUnitClassesView(BuildContext context) {
-    return LazyConsumer<CourseUnitsInfoProvider>(
-      builder: (context, courseUnitsInfoProvider) {
-        return RequestDependentWidgetBuilder(
-          onNullContent: Center(
-            child: Text(
-              S.of(context).no_class,
-              textAlign: TextAlign.center,
-            ),
-          ),
-          status: courseUnitsInfoProvider.status,
-          builder: () => CourseUnitClassesView(
-            courseUnitsInfoProvider.courseUnitsClasses[widget.courseUnit]!,
-          ),
-          hasContentPredicate:
-              courseUnitsInfoProvider.courseUnitsClasses[widget.courseUnit] !=
-                      null &&
-                  courseUnitsInfoProvider
-                      .courseUnitsClasses[widget.courseUnit]!.isNotEmpty,
-        );
-      },
-    );
+    final classes = context
+        .read<CourseUnitsInfoProvider>()
+        .courseUnitsClasses[widget.courseUnit];
+
+    if (classes == null || classes.isEmpty) {
+      return Center(
+        child: Text(
+          S.of(context).no_class,
+          textAlign: TextAlign.center,
+        ),
+      );
+    }
+
+    return CourseUnitClassesView(classes);
   }
 }

uni/lib/view/lazy_consumer.dart

@@ -69,9 +69,7 @@ class LazyConsumer<T extends StateProviderNotifier> extends StatelessWidget {
 
       // Finally, complete provider initialization
       if (context.mounted) {
-        // This will fail if the session initialization failed.
-        // That is the expected behavior.
-        await sessionFuture!.then((_) async {
+        await sessionFuture?.then((_) async {
           await provider!.ensureInitializedFromRemote(context);
         });
       }