Merge pull request #71 from flutter-news-app-full-source-code/Optimize-Content-Management-Tab-Switching-to-Prevent-Redundant-Data-Fetches

Optimize content management tab switching to prevent redundant data fetches

Author: fulleni

lib/content_management/bloc/content_management_bloc.dart

@@ -42,19 +42,28 @@ class ContentManagementBloc
     _headlineUpdateSubscription = _headlinesRepository.entityUpdated
         .where((type) => type == Headline)
         .listen((_) {
-          add(const LoadHeadlinesRequested(limit: kDefaultRowsPerPage));
+          add(const LoadHeadlinesRequested(
+            limit: kDefaultRowsPerPage,
+            forceRefresh: true,
+          ));
         });
 
     _topicUpdateSubscription = _topicsRepository.entityUpdated
         .where((type) => type == Topic)
         .listen((_) {
-          add(const LoadTopicsRequested(limit: kDefaultRowsPerPage));
+          add(const LoadTopicsRequested(
+            limit: kDefaultRowsPerPage,
+            forceRefresh: true,
+          ));
         });
 
     _sourceUpdateSubscription = _sourcesRepository.entityUpdated
         .where((type) => type == Source)
         .listen((_) {
-          add(const LoadSourcesRequested(limit: kDefaultRowsPerPage));
+          add(const LoadSourcesRequested(
+            limit: kDefaultRowsPerPage,
+            forceRefresh: true,
+          ));
         });
   }
 
@@ -85,6 +94,15 @@ class ContentManagementBloc
     LoadHeadlinesRequested event,
     Emitter<ContentManagementState> emit,
   ) async {
+    // If headlines are already loaded and it's not a pagination request,
+    // do not re-fetch. This prevents redundant API calls on tab changes.
+    if (state.headlinesStatus == ContentManagementStatus.success &&
+        state.headlines.isNotEmpty &&
+        event.startAfterId == null &&
+        !event.forceRefresh) {
+      return;
+    }
+
     emit(state.copyWith(headlinesStatus: ContentManagementStatus.loading));
     try {
       final isPaginating = event.startAfterId != null;
@@ -166,6 +184,15 @@ class ContentManagementBloc
     LoadTopicsRequested event,
     Emitter<ContentManagementState> emit,
   ) async {
+    // If topics are already loaded and it's not a pagination request,
+    // do not re-fetch. This prevents redundant API calls on tab changes.
+    if (state.topicsStatus == ContentManagementStatus.success &&
+        state.topics.isNotEmpty &&
+        event.startAfterId == null &&
+        !event.forceRefresh) {
+      return;
+    }
+
     emit(state.copyWith(topicsStatus: ContentManagementStatus.loading));
     try {
       final isPaginating = event.startAfterId != null;
@@ -247,6 +274,15 @@ class ContentManagementBloc
     LoadSourcesRequested event,
     Emitter<ContentManagementState> emit,
   ) async {
+    // If sources are already loaded and it's not a pagination request,
+    // do not re-fetch. This prevents redundant API calls on tab changes.
+    if (state.sourcesStatus == ContentManagementStatus.success &&
+        state.sources.isNotEmpty &&
+        event.startAfterId == null &&
+        !event.forceRefresh) {
+      return;
+    }
+
     emit(state.copyWith(sourcesStatus: ContentManagementStatus.loading));
     try {
       final isPaginating = event.startAfterId != null;

lib/content_management/bloc/content_management_event.dart

@@ -26,16 +26,23 @@ final class ContentManagementTabChanged extends ContentManagementEvent {
 /// {@endtemplate}
 final class LoadHeadlinesRequested extends ContentManagementEvent {
   /// {@macro load_headlines_requested}
-  const LoadHeadlinesRequested({this.startAfterId, this.limit});
+  const LoadHeadlinesRequested({
+    this.startAfterId,
+    this.limit,
+    this.forceRefresh = false,
+  });
 
   /// Optional ID to start pagination after.
   final String? startAfterId;
 
   /// Optional maximum number of items to return.
   final int? limit;
 
+  /// If true, forces a refresh of the data, bypassing the cache.
+  final bool forceRefresh;
+
   @override
-  List<Object?> get props => [startAfterId, limit];
+  List<Object?> get props => [startAfterId, limit, forceRefresh];
 }
 
 /// {@template archive_headline_requested}
@@ -57,16 +64,23 @@ final class ArchiveHeadlineRequested extends ContentManagementEvent {
 /// {@endtemplate}
 final class LoadTopicsRequested extends ContentManagementEvent {
   /// {@macro load_topics_requested}
-  const LoadTopicsRequested({this.startAfterId, this.limit});
+  const LoadTopicsRequested({
+    this.startAfterId,
+    this.limit,
+    this.forceRefresh = false,
+  });
 
   /// Optional ID to start pagination after.
   final String? startAfterId;
 
   /// Optional maximum number of items to return.
   final int? limit;
 
+  /// If true, forces a refresh of the data, bypassing the cache.
+  final bool forceRefresh;
+
   @override
-  List<Object?> get props => [startAfterId, limit];
+  List<Object?> get props => [startAfterId, limit, forceRefresh];
 }
 
 /// {@template archive_topic_requested}
@@ -88,16 +102,23 @@ final class ArchiveTopicRequested extends ContentManagementEvent {
 /// {@endtemplate}
 final class LoadSourcesRequested extends ContentManagementEvent {
   /// {@macro load_sources_requested}
-  const LoadSourcesRequested({this.startAfterId, this.limit});
+  const LoadSourcesRequested({
+    this.startAfterId,
+    this.limit,
+    this.forceRefresh = false,
+  });
 
   /// Optional ID to start pagination after.
   final String? startAfterId;
 
   /// Optional maximum number of items to return.
   final int? limit;
 
+  /// If true, forces a refresh of the data, bypassing the cache.
+  final bool forceRefresh;
+
   @override
-  List<Object?> get props => [startAfterId, limit];
+  List<Object?> get props => [startAfterId, limit, forceRefresh];
 }
 
 /// {@template archive_source_requested}