feat: stop loading new messages while autoscroll is on and stop loading old messages if there are no new results

CHANGELOG.md

@@ -22,6 +22,7 @@
 - Added senderTitleResolver to the ChatOptions to resolve the title of the sender in the chat message
 - Added imageProviderResolver to the ChatOptions to resolve ImageProvider for all images in the userstory
 - Added enabled boolean to the messageInputBuilder and made parameters named
+- Added autoScrollTriggerOffset to the ChatPaginationControls to adjust when the auto scroll should be enabled
 
 ## 4.0.0
 - Move to the new user story architecture

packages/flutter_chat/lib/src/config/chat_options.dart

@@ -294,6 +294,7 @@ class ChatPaginationControls {
   /// The chat pagination controls constructor
   const ChatPaginationControls({
     this.scrollOffset = 50.0,
+    this.autoScrollTriggerOffset = 50.0,
     this.loadingIndicatorForNewMessages = true,
     this.loadingIndicatorForOldMessages = true,
     this.loadingNewMessageMinDuration = Duration.zero,
@@ -304,6 +305,10 @@ class ChatPaginationControls {
   /// on both sides of the chat. Defaults to 50.0
   final double scrollOffset;
 
+  /// The minimum scroll offset to trigger the auto scroll to the bottom of the
+  /// chat. Defaults to 50.0
+  final double autoScrollTriggerOffset;
+
   /// Whether to show a loading indicator for new messages loading
   final bool loadingIndicatorForNewMessages;
 

packages/flutter_chat/lib/src/screens/chat_detail/chat_detail_screen.dart

@@ -256,6 +256,9 @@ class _ChatBody extends HookWidget {
 
     var isLoadingOlder = useState(false);
     var isLoadingNewer = useState(false);
+
+    var hasMoreOlder = useState(true);
+
     var autoScrollEnabled = useState(true);
 
     var messagesStream = useMemoized(
@@ -268,7 +271,9 @@ class _ChatBody extends HookWidget {
     var scrollController = useScrollController();
 
     Future<void> loadOlderMessages() async {
-      if (messages.isEmpty || isLoadingOlder.value) return;
+      if (!hasMoreOlder.value || messages.isEmpty || isLoadingOlder.value) {
+        return;
+      }
       isLoadingOlder.value = true;
 
       var oldestMsg = messages.first;
@@ -292,7 +297,9 @@ class _ChatBody extends HookWidget {
             return;
           }
           var newCount = messages.length;
-          if (newCount > oldCount) {
+          if (newCount == oldCount) {
+            hasMoreOlder.value = false;
+          } else {
             var newMaxScroll = scrollController.position.maxScrollExtent;
             var diff = newMaxScroll - oldMaxScroll;
             scrollController.jumpTo(oldOffset + diff);
@@ -329,22 +336,26 @@ class _ChatBody extends HookWidget {
         var offset = scrollController.offset;
         var maxScroll = scrollController.position.maxScrollExtent;
         var threshold = options.paginationControls.scrollOffset;
+        var autoScrollThreshold =
+            options.paginationControls.autoScrollTriggerOffset;
 
         var distanceFromBottom = maxScroll - offset;
 
-        if (distanceFromBottom > 50) {
-          autoScrollEnabled.value = false;
-        } else {
-          autoScrollEnabled.value = true;
-        }
-
         if (offset <= threshold && !isLoadingOlder.value) {
           unawaited(loadOlderMessages());
         }
 
-        if (distanceFromBottom <= threshold && !isLoadingNewer.value) {
+        if (distanceFromBottom <= threshold &&
+            !isLoadingNewer.value &&
+            !autoScrollEnabled.value) {
           unawaited(loadNewerMessages());
         }
+
+        if (distanceFromBottom > autoScrollThreshold) {
+          autoScrollEnabled.value = false;
+        } else {
+          autoScrollEnabled.value = true;
+        }
       }
 
       scrollController.addListener(onScroll);