Imported from cometchat/cometchat-skills (skills/cometchat-flutter-v5-core/SKILL.md). Install upstream with npx skills add cometchat/cometchat-skills --skill cometchat-flutter-v5-core. Copyright stays with the author (MIT).

CometChat Flutter UIKit v5 — Core Rules

Ground truth: cometchat_chat_uikit: ^5.2 (GetX-based; pair with cometchat_calls_uikit: ^5.0 / raw cometchat_calls_sdk ^5.0.2 for calls) — the pub-cache package source + docs/ui-kit/flutter/v5. Official docs: https://www.cometchat.com/docs/ui-kit/flutter/v5/overview · Docs MCP: claude mcp add --transport http cometchat-docs https://www.cometchat.com/docs/mcp (or fetch the URL directly without MCP). V5 is legacy/maintenance-only (V6 is current); verify Dart symbols against the resolved package source.

Non-negotiable constraints for all CometChat UIKit v5 code. Violating these causes silent failures or crashes.

Key v5 Architecture Facts

• State management: GetX (GetBuilder, GetxController, Get.put, Get.find, Get.delete)
• Separate packages: cometchat_chat_uikit + cometchat_calls_uikit + cometchat_uikit_shared
• SDK: cometchat_sdk ^4.1.2 + cometchat_calls_sdk ^4.2.2 (chat-kit baseline). For voice/video calling, do NOT use cometchat_calls_uikit (4.x-bound) — integrate the raw cometchat_calls_sdk ^5.0.2 per cometchat-flutter-v5-calls (the V5-canonical calls path).
• Imports — two barrels. For chat-only projects: package:cometchat_chat_uikit/cometchat_chat_uikit.dart. For projects that also need voice/video calling: ADD package:cometchat_calls_uikit/cometchat_calls_uikit.dart as a SECOND import — the calls barrel re-exports shared + SDK only and does NOT re-export cometchat_chat_uikit. Chat widgets like CometChatConversations, CometChatMessageList, CometChatMessageComposer are reachable only through the chat barrel.
• CometChatUIKit.login(uid) takes a String directly (not an object)
• No ServiceLocator pattern — controllers are created via Get.put() internally
• Style classes use ThemeExtension with merge() pattern

Rule: INIT_FIRST

CometChatUIKit.init() must complete before any login, component usage, or SDK call.

// ✅ CORRECT
final settings = (UIKitSettingsBuilder()
      ..appId = 'APP_ID'
      ..region = 'us'
      ..authKey = 'AUTH_KEY'
      ..subscriptionType = CometChatSubscriptionType.allUsers)
    .build();

CometChatUIKit.init(
  uiKitSettings: settings,
  onSuccess: (_) => debugPrint('Init done'),
  onError: (e) => debugPrint('Init failed: ${e.message}'),
);

// ❌ WRONG — login before init completes
CometChatUIKit.init(uiKitSettings: settings);
CometChatUIKit.login('uid'); // Race condition

Rule: AUTH_CHECK_AFTER_INIT

After CometChatUIKit.init() completes, the static field CometChatUIKit.loggedInUser is populated if a cached session exists (init internally calls getLoggedInUser()). You can check it synchronously in onSuccess, or use CometChatUIKit.getLoggedInUser() for an explicit async check.

// ✅ CORRECT — synchronous check after init
CometChatUIKit.init(
  uiKitSettings: settings,
  onSuccess: (_) {
    final hasUser = CometChatUIKit.loggedInUser != null;
    // Route to home or login
  },
);

// ✅ ALSO CORRECT — explicit async check (used by master app)
CometChatUIKit.init(
  uiKitSettings: settings,
  onSuccess: (_) async {
    final user = await CometChatUIKit.getLoggedInUser();
    if (user != null) {
      await CometChatUIKit.login(user.uid, onSuccess: ...);
    }
  },
);

Note: CometChatUIKit.login() handles re-login gracefully — if the user is already logged in with the same UID, it returns the cached user without hitting the server.

Rule: LISTENER_LIFECYCLE

SDK listeners MUST be registered with a unique ID in initState() (or GetxController onInit()) and removed in dispose() (or onClose()).

// ✅ CORRECT
class _MyScreenState extends State<MyScreen> with MessageListener {
  late final String _listenerId;

  @override
  void initState() {
    super.initState();
    _listenerId = 'my_screen_${DateTime.now().millisecondsSinceEpoch}';
    CometChat.addMessageListener(_listenerId, this);
  }

  @override
  void dispose() {
    CometChat.removeMessageListener(_listenerId);
    super.dispose();
  }
}

// ❌ WRONG — hardcoded ID causes collisions; missing dispose removal
CometChat.addMessageListener('messages', this); // Collision!

Rule: THEME_CACHE

Cache theme values in didChangeDependencies() — unconditionally, no flag needed. Never call CometChatThemeHelper.getColorPalette(context) in build().

getColorPalette() creates a new CometChatColorPalette object every call, resolving each token individually via Theme.of(context). During keyboard animation, MediaQuery changes trigger rebuilds, making this expensive in build().

// ✅ CORRECT — matches actual package pattern (no flag)
@override
void didChangeDependencies() {
  super.didChangeDependencies();
  colorPalette = CometChatThemeHelper.getColorPalette(context);
  spacing = CometChatThemeHelper.getSpacing(context);
  typography = CometChatThemeHelper.getTypography(context);
}

// ❌ WRONG — lookup in build causes jank
@override
Widget build(BuildContext context) {
  final colors = CometChatThemeHelper.getColorPalette(context); // Expensive!
  return Container(color: colors.primary);
}

Do NOT use a _themeInitialized flag — it prevents theme updates when the system switches between light/dark mode.

Rule: SUBSCRIPTION_TYPE_REQUIRED

Omitting subscriptionType in UIKitSettingsBuilder silently disables all presence events (online/offline, typing indicators). No error is thrown.

// ✅ CORRECT
UIKitSettingsBuilder()
  ..subscriptionType = CometChatSubscriptionType.allUsers

Rule: REGION_LOWERCASE

Region must be a lowercase string: 'us', 'eu', or 'in'.

Rule: MUID_PRESERVATION

When handling ccMessageSent events, compare by muid first, then id — the SDK may return an empty muid in the success callback.

Pattern: Callback → Async Bridge (Completer)

import 'dart:async';

Future<bool> initAsync(UIKitSettings settings) {
  final completer = Completer<bool>();
  CometChatUIKit.init(
    uiKitSettings: settings,
    onSuccess: (_) => completer.complete(true),
    onError: (e) => completer.complete(false),
  );
  return completer.future;
}

v5 Component Architecture Pattern (GetX)

{component}/
├── cometchat_{component}.dart              # StatefulWidget
├── cometchat_{component}_controller.dart   # extends GetxController
├── cometchat_{component}_style.dart        # ThemeExtension with merge()
└── {component}_builder_protocol.dart       # Request builder protocol

Internal lifecycle:

@override
void initState() {
  super.initState();
  tag = widget.controllerTag ?? 'default_tag_${DateTime.now().millisecondsSinceEpoch}';
  controller = Get.put<Controller>(Controller(...), tag: tag);
}

@override
void dispose() {
  if (widget.controllerTag == null) {
    Get.delete<Controller>(tag: tag);
  }
  super.dispose();
}

Android Build Requirements

• android.useAndroidX=true and android.enableJetifier=true in gradle.properties
• minSdk 26 in android/app/build.gradle
• ProGuard: -keep class com.cometchat.** { *; } and -keep interface com.cometchat.** { *; }

Top 10 Error Debugging

Checklist — Every CometChat v5 Screen

• CometChatUIKit.init() called before any usage
• subscriptionType set in UIKitSettingsBuilder
• region is lowercase
• Theme cached in didChangeDependencies(), not build()
• SDK listeners registered with unique ID, removed in dispose()
• Colors from CometChatThemeHelper, never hardcoded
• Imports: package:cometchat_chat_uikit/cometchat_chat_uikit.dart always; ADD package:cometchat_calls_uikit/cometchat_calls_uikit.dart if you use voice/video

Visual Builder integration

Flutter V5 is the primary home for Visual Builder integration. The canonical repo at the chat_builder/ directory inside the Flutter Visual Builder ZIP (download from https://preview.cometchat.com/downloads/cometchat-builder-flutter.zip) ships V5-shaped code — cometchat_chat_uikit: ^5.2.12 + cometchat_calls_uikit: ^5.0.13. The integration copies the entire chat_builder/ directory as a path: dependency, then BuilderSettingsHelper.loadFromAsset() reads chat_builder/assets/sample_app/cometchat-builder-settings.json and configures the bundled chat UI accordingly.

The full recipe lives in cometchat-flutter-v6-core §"Visual Builder integration" because that's where the V6-prep restructure originally landed the validated content. Both skills reference the same canonical; the V6 page carries a "V5-shaped code" warning at the top. V5 customers should follow that recipe AS-IS — the canonical IS V5-targeted.

Validated 2026-05-21 against Flutter 3.38.3: flutter build apk --debug produces app-debug.apk after applying:

• Envelope-wrapped JSON at chat_builder/assets/sample_app/cometchat-builder-settings.json. The CLI (source of truth) writes { builderId, name, settings: {...} }; the vendor canonical's own checked-in file carries only { builderId, settings } (no name). BuilderSettingsHelper.loadFromAsset() reads only builderId + settings and ignores any extra top-level keys, so the CLI's extra name is harmless.
• Two missing-field defaults injected pre-write (mentionAll + inAppSounds — same as Android)
• android.enableJetifier=true in android/gradle.properties (the chat SDK pulls com.android.support transitively)
• await BuilderSettingsHelper.loadFromAsset() in lib/main.dart before runApp()
• chat_builder: { path: ./chat_builder } in host pubspec.yaml

Differences from the V6 page's recipe text:

• V5 host code uses StatefulWidget with direct listener management (V6 uses BLoC pattern); both work with the embedded chat_builder package since it owns its own state.
• V5 calls (the standalone cometchat-flutter-v5-calls flow, outside the builder) don't need the [[project_v6_flutter_calls_partial]] navigatorKey workaround — that's a V6-specific incoming-call-routing requirement. However, the Visual Builder canonical itself (V5-shaped) wires navigatorKey: CallNavigationContext.navigatorKey UNCONDITIONALLY in every MaterialApp ChatBuilder.createApp() builds, regardless of whether calls are enabled — so if you mount ChatBuilder.createApp() (recommended) or replicate its MaterialApp in a host wrapper, keep that navigator key in place. Do NOT gate it behind "calls enabled". See the v6-core recipe's wrapper guidance.