From b9866a709aa326755909ad0a80729b85f9782118 Mon Sep 17 00:00:00 2001
From: Gordon Hayes <pggordonhayes@gmail.com>
Date: Wed, 6 Oct 2021 15:35:22 +0200
Subject: [PATCH] feat: add messagesIndex to keep track of list indexes

---
 .../lib/src/message_list_view.dart                   | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/packages/stream_chat_flutter/lib/src/message_list_view.dart b/packages/stream_chat_flutter/lib/src/message_list_view.dart
index 56e3d48d..b6ea7ff1 100644
--- a/packages/stream_chat_flutter/lib/src/message_list_view.dart
+++ b/packages/stream_chat_flutter/lib/src/message_list_view.dart
@@ -336,6 +336,8 @@ class _MessageListViewState extends State<MessageListView> {
 
   List<Message> messages = <Message>[];
 
+  Map<String, int> messagesIndex = {};
+
   bool initialMessageHighlightComplete = false;
 
   bool _inBetweenList = false;
@@ -379,6 +381,9 @@ class _MessageListViewState extends State<MessageListView> {
 
   Widget _buildListView(List<Message> data) {
     messages = data;
+    for (var index = 0; index < messages.length; index++) {
+      messagesIndex[messages[index].id] = index;
+    }
     final newMessagesListLength = messages.length;
 
     if (_messageListLength != null) {
@@ -471,9 +476,10 @@ class _MessageListViewState extends State<MessageListView> {
                   itemCount: messages.length,
                   findChildIndexCallback: (Key key) {
                     final indexedKey = key as IndexedKey;
-                    final index = messages.indexWhere(
-                        (element) => element.id == indexedKey.value);
-                    return ((index + 2) * 2) - 1;
+                    final index = messagesIndex[indexedKey.value];
+                    if (index != null) {
+                      return ((index + 2) * 2) - 1;
+                    }
                   },
 
                   // Item Count -> 8 (1 parent, 2 header+footer, 2 top+bottom, 3 messages)