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CometChat Flutter UIKit v6 — Troubleshooting Guide

Comprehensive guide for diagnosing and fixing CometChat Flutter UIKit v6 integration problems.

1. Quick Diagnosis Flow

Use this decision tree to jump to the right section:

What's happening?
│
├─ App crashes or errors on startup
│  └─ Go to → Section 2: Init & Login Errors
│
├─ UI looks wrong, layout broken, keyboard issues
│  └─ Go to → Section 3: UI Rendering Issues
│
├─ Calls not working, call screen blank or stuck
│  └─ Go to → Section 4: Call Issues
│
├─ Events not firing, duplicate events, memory leaks
│  └─ Go to → Section 5: Listener Issues
│
├─ Build fails on Android or iOS
│  └─ Go to → Section 6: Build Errors
│
├─ App is slow, janky scrolling, laggy keyboard
│  └─ Go to → Section 7: Performance Issues
│
└─ Platform-specific weirdness (Android/iOS/Web)
   └─ Go to → Section 8: Platform-Specific Issues

2. Init & Login Errors

2.1 "Authentication null"

• Symptom: Error message Authentication null or Please log in to CometChat before calling this method when using any CometChat component or SDK call.
• Cause: CometChatUIKit.init() was not called, or was called but not awaited before using components or calling login.
• Fix: Ensure init() completes before any other CometChat usage:

// ✅ CORRECT — await init before anything else
final settings = (UIKitSettingsBuilder()
      ..appId = 'APP_ID'
      ..region = 'us'
      ..authKey = 'AUTH_KEY'
      ..subscriptionType = CometChatSubscriptionType.allUsers)
    .build();

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

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

2.2 "APP ID null"

• Symptom: Error APP ID null or appId is required during init.
• Cause: appId not set in UIKitSettingsBuilder.
• Fix: Set appId before calling .build():

final settings = (UIKitSettingsBuilder()
      ..appId = 'YOUR_APP_ID'  // ← Must be set
      ..region = 'us'
      ..authKey = 'YOUR_AUTH_KEY')
    .build();

2.3 ERR_ALREADY_LOGGED_IN

• Symptom: Error ERR_ALREADY_LOGGED_IN when calling CometChatUIKit.login().
• Cause: Calling login when a session already exists. After init(), the SDK restores cached sessions automatically.
• Fix: Check CometChatUIKit.loggedInUser after init before calling login:

CometChatUIKit.init(
  uiKitSettings: settings,
  onSuccess: (_) {
    if (CometChatUIKit.loggedInUser != null) {
      // Already logged in — skip login, go to home
      navigateToHome();
    } else {
      // No session — show login screen
      navigateToLogin();
    }
  },
);

2.4 "Android internal error" on login

• Symptom: Login fails with a vague Android internal error message.
• Cause: Multiple possible causes — incorrect auth key, UID doesn't exist in CometChat dashboard, beta SDK bug, or network issue.
• Fix:
  1. Verify credentials are correct in the CometChat dashboard
  2. Verify the UID exists in the dashboard
  3. Try calling CometChat.login(uid, authKey) directly to isolate UIKit vs SDK issue
  4. If using beta SDK, try the stable release
  5. Check network connectivity and firewall rules

2.5 Guard screen stuck on spinner

• Symptom: App shows a loading spinner forever after init. The auth guard never resolves.
• Cause: Using the callback-based CometChat.getLoggedInUser() after init instead of the synchronous CometChatUIKit.loggedInUser. The callback API silently fails when no session exists — neither onSuccess nor onError fires.
• Fix: Use the synchronous check after init:

// ✅ CORRECT — synchronous check, always resolves
CometChatUIKit.init(
  uiKitSettings: settings,
  onSuccess: (_) {
    final hasUser = CometChatUIKit.loggedInUser != null;
    setState(() {
      _loggedIn = hasUser;
      _initializing = false;
    });
  },
);

// ❌ WRONG — callback may never fire when no session exists
CometChatUIKit.init(
  uiKitSettings: settings,
  onSuccess: (_) {
    CometChat.getLoggedInUser(
      onSuccess: (user) { /* may never fire */ },
      onError: (e) { /* may never fire */ },
    );
  },
);

// ❌ ALSO WRONG — redundant native bridge round-trip
CometChatUIKit.init(
  uiKitSettings: settings,
  onSuccess: (_) async {
    final user = await CometChatUIKit.getLoggedInUser(); // Unnecessary!
  },
);

2.6 Region error (ERR_INVALID_REGION)

• Symptom: Init fails with ERR_INVALID_REGION.
• Cause: Region string is uppercase or not one of the valid values.
• Fix: Use lowercase region string — valid values are 'us', 'eu', 'in':

// ✅ CORRECT
..region = 'us'

// ❌ WRONG
..region = 'US'
..region = 'United States'

2.7 StateError from uninitialized ServiceLocator

• Symptom: StateError: not initialized when creating a BLoC manually.
• Cause: Component's ServiceLocator.instance.setup() was not called before creating the BLoC. UIKit widgets do this automatically, but manual BLoC creation requires it.
• Fix: Call setup before creating the BLoC:

// ✅ CORRECT
ConversationsServiceLocator.instance.setup();
final bloc = ConversationsBloc(
  getLoggedInUserUseCase: ConversationsServiceLocator.instance.getLoggedInUserUseCase,
);

// ❌ WRONG — setup not called
final bloc = ConversationsBloc(
  getLoggedInUserUseCase: ConversationsServiceLocator.instance.getLoggedInUserUseCase,
);

3. UI Rendering Issues

3.1 Stale user/group data

• Symptom: User name, avatar, or group info doesn't update in real-time. Old data persists even after changes.
• Cause: Passing widget.user or widget.group directly to UIKit components instead of maintaining mutable state that updates from listeners.
• Fix: Keep mutable _user/_group in your State class and update from SDK listeners:

class _MessagesScreenState extends State<MessagesScreen> {
  late User? _user;
  late Group? _group;

  @override
  void initState() {
    super.initState();
    _user = widget.user;
    _group = widget.group;
    // Register listeners to update _user/_group on changes
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        children: [
          Expanded(child: CometChatMessageList(user: _user, group: _group)),
          CometChatMessageComposer(user: _user, group: _group),
        ],
      ),
    );
  }
}

3.2 No typing indicators / presence events

• Symptom: Online/offline status never updates. Typing indicators don't appear. No presence events fire. No error is thrown.
• Cause: subscriptionType was not set in UIKitSettingsBuilder. Omitting it silently disables all presence events.
• Fix: Always set subscriptionType:

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

// ❌ WRONG — no error, but presence events never fire
UIKitSettingsBuilder()
  ..appId = 'APP_ID'
  ..region = 'us'
  ..authKey = 'AUTH_KEY'
  // subscriptionType missing!

3.3 Messages not updating in real-time

• Symptom: New messages don't appear until the screen is refreshed or re-opened.
• Cause: Multiple possible causes:
  1. SDK message listener not registered (BLoC handles this automatically — check component is mounted)
  2. subscriptionType not set (see 3.2)
  3. Component was disposed and listener removed
• Fix:
  1. Ensure subscriptionType is set in UIKitSettings
  2. Verify the CometChatMessageList widget is mounted and not disposed
  3. If using custom BLoC, ensure it registers CometChat.addMessageListener() in its constructor and removes it in close()

3.4 Theme jank during keyboard animation

• Symptom: Visible jank (stuttering, dropped frames) when the keyboard opens or closes, especially on message screens.
• Cause: Theme values (CometChatThemeHelper.getColorPalette(context), etc.) are being looked up inside build(). During keyboard animation, MediaQuery changes trigger rebuilds, and each lookup does expensive InheritedWidget traversal (44–95ms instead of <16ms).
• Fix: Cache theme values in didChangeDependencies() with a _themeInitialized flag:

// ✅ CORRECT — cache once, reuse on every build
class _MyWidgetState extends State<MyWidget> {
  late CometChatColorPalette _colorPalette;
  late CometChatSpacing _spacing;
  late CometChatTypography _typography;
  bool _themeInitialized = false;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    if (!_themeInitialized) {
      _colorPalette = CometChatThemeHelper.getColorPalette(context);
      _spacing = CometChatThemeHelper.getSpacing(context);
      _typography = CometChatThemeHelper.getTypography(context);
      _themeInitialized = true;
    }
  }

  @override
  Widget build(BuildContext context) {
    // Use _colorPalette, _spacing, _typography — no lookups here
    return Container(color: _colorPalette.primary);
  }
}

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

3.5 Extra white space between composer and keyboard

• Symptom: Visible gap between the message composer and the keyboard when it opens.
• Cause: Safe area bottom padding being applied when the keyboard is open. The keyboard already covers the safe area, so adding safe area padding on top creates extra space.
• Fix: Always use MediaQuery.paddingOf(context).bottom for safe area (set once in didChangeDependencies()). Never overwrite it with native plugin values. The SliverSpacing widget handles this automatically — ensure you're not adding extra SafeArea wrappers around the composer.

4. Call Issues

4.1 "auth token null" on call init

• Symptom: Calls SDK fails with auth token null or similar authentication error when trying to start a call.
• Cause: The Calls SDK was initialized before the Chat SDK completed init and login. The Calls SDK needs the auth token from a successful chat login.
• Fix: Ensure CometChatUIKit.init() and login complete before any calls-related initialization. The UIKit handles this order internally — if you're initializing calls manually, ensure the chat session is established first.

4.2 "session already started"

• Symptom: Error session already started when trying to join or start a call.
• Cause: A previous call session was not properly ended. This can happen if the user navigated away from the call screen without ending the call, or if the app was killed during a call.
• Fix: Ensure call sessions are properly ended when leaving call screens. If the error persists, call CometChat.endCall() or CometChat.rejectCall() to clean up the stale session before starting a new one.

4.3 "CallManager not found" / "Calling module not found"

• Symptom: Android native error CallManager not found or CometChat Calling module not found.
• Cause: The CometChat Calling native module is not properly linked on Android. This can happen with ProGuard stripping, missing dependencies, or build configuration issues.
• Fix:
  1. Ensure ProGuard keep rules are in place (see Section 6.1)
  2. Verify cometchat_chat_uikit is properly added to pubspec.yaml
  3. Run flutter clean and rebuild
  4. Check that android.enableJetifier=true is in gradle.properties

4.4 "startSession null" on Android

• Symptom: startSession returns null on Android with no error feedback. The call screen may appear blank or stuck.
• Cause: Known Android SDK issue where startSession silently fails. A 5-second timeout workaround exists but provides no error feedback.
• Fix: This is a known SDK-level issue. Workarounds:
  1. Implement a timeout wrapper around startSession calls
  2. Show a retry option to the user if the call screen doesn't load within 5 seconds
  3. Check for updates to cometchat_calls_sdk that may fix this

4.5 Incoming call not received

• Symptom: Incoming calls are not shown to the receiver. The caller sees the outgoing call screen but the receiver gets nothing.
• Cause: Multiple possible causes:
  1. subscriptionType not set (presence/events disabled)
  2. Push notification / VoIP setup incomplete
  3. Call listeners not registered
  4. App is in background without proper background handling
• Fix:
  1. Ensure subscriptionType is set to CometChatSubscriptionType.allUsers
  2. Verify FCM/APNs push notification setup for background calls
  3. Check that call event listeners are registered
  4. For cross-platform issues (Android↔iOS↔React), verify all platforms are on compatible SDK versions

4.6 Calls SDK not re-initialized after logout

• Symptom: After logout and re-login, calls don't work. Call screens may be blank or throw errors.
• Cause: The Calls SDK maintains its own session state. After CometChatUIKit.logout(), the Calls SDK session is invalidated but may not be properly re-initialized on the next login.
• Fix: Ensure the Calls SDK is re-initialized after login. The UIKit handles this internally — if you're managing calls manually, call the Calls SDK init after each successful login.

5. Listener Issues

5.1 Duplicate events (hardcoded listener IDs)

• Symptom: Event handlers fire multiple times for a single event. Messages appear twice, typing indicators flicker.
• Cause: Listener registered with a hardcoded ID. When the widget is recreated (e.g., navigation), the new listener overwrites the old one but the old widget's handler may still be referenced, or multiple instances collide.
• Fix: Use a unique listener ID per widget instance:

// ✅ CORRECT — unique ID per instance
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 across instances
CometChat.addMessageListener('messages', this); // Collision!

5.2 Listener leaks (missing dispose)

• Symptom: Memory usage grows over time. Events fire on screens that are no longer visible. App becomes sluggish.
• Cause: SDK listeners registered in initState() but not removed in dispose().
• Fix: Always remove listeners with the same ID used to register:

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

5.3 No events firing (subscriptionType not set)

• Symptom: All listeners are properly registered and removed, but no events ever fire. No errors in console.
• Cause: subscriptionType not set in UIKitSettingsBuilder. This silently disables all real-time events.
• Fix: Set subscriptionType during init:

UIKitSettingsBuilder()
  ..subscriptionType = CometChatSubscriptionType.allUsers

6. Build Errors

6.1 Android: ClassNotFoundException (missing ProGuard rules)

• Symptom: Release build crashes with ClassNotFoundException for CometChat classes. Debug builds work fine.
• Cause: R8/ProGuard strips CometChat SDK classes during release minification.
• Fix: Create android/app/proguard-rules.pro with:

# CometChat — prevent R8 from stripping SDK classes
-keep class com.cometchat.** { *; }
-keep interface com.cometchat.** { *; }

# Suppress warnings for Calls SDK classes referenced cross-module
-dontwarn com.cometchat.calls.CometChatRTCView$CometChatRTCViewBuilder
-dontwarn com.cometchat.calls.CometChatRTCView
-dontwarn com.cometchat.calls.CometChatRTCViewListener
-dontwarn com.cometchat.calls.model.AnalyticsSettings
-dontwarn com.cometchat.calls.model.RTCCallback
-dontwarn com.cometchat.calls.model.RTCReceiver

Reference it in android/app/build.gradle:

buildTypes {
    release {
        isMinifyEnabled = true
        isShrinkResources = true
        proguardFiles(
            getDefaultProguardFile("proguard-android-optimize.txt"),
            "proguard-rules.pro"
        )
    }
}

6.2 Android: minSdk too low

• Symptom: Build fails with error about minimum SDK version. Error mentions minSdkVersion incompatibility.
• Cause: minSdk is set below 26. The cometchat_calls_sdk requires minSdk 26.
• Fix: In android/app/build.gradle (or .kts):

defaultConfig {
    minSdk = 26  // Required by cometchat_calls_sdk
}

6.3 Android: Jetifier missing

• Symptom: Build fails with errors about Android Support Library classes not found, or androidx conflicts.
• Cause: android.enableJetifier=true not set. Transitive dependencies from the CometChat SDK use old Android Support Library references.
• Fix: In android/gradle.properties:

android.useAndroidX=true
android.enableJetifier=true

6.4 iOS: pod install failures

• Symptom: pod install fails with dependency resolution errors, version conflicts, or missing pods.
• Cause: Cocoapods cache is stale, or the Podfile needs updating.
• Fix:

cd ios
rm -rf Pods Podfile.lock
pod repo update
pod install --repo-update
cd ..
flutter clean
flutter pub get

If still failing, check that the iOS deployment target in ios/Podfile is high enough:

platform :ios, '13.0'  # Minimum for CometChat

6.5 iOS: missing permissions

• Symptom: App crashes or shows blank screen when trying to access camera, microphone, or photo library on iOS.
• Cause: Required permission descriptions missing from Info.plist.
• Fix: Add to ios/Runner/Info.plist:

<key>NSCameraUsageDescription</key>
<string>Camera access is needed for video calls and sending photos</string>
<key>NSMicrophoneUsageDescription</key>
<string>Microphone access is needed for voice and video calls</string>
<key>NSPhotoLibraryUsageDescription</key>
<string>Photo library access is needed for sending images</string>

For VoIP calls, also add:

<key>UIBackgroundModes</key>
<array>
    <string>voip</string>
    <string>remote-notification</string>
</array>

7. Performance Issues

7.1 Theme lookup in build() causing jank

• Symptom: Dropped frames during scrolling or keyboard animation. Flutter DevTools shows long build times (44–95ms).
• Cause: CometChatThemeHelper.getColorPalette(context) and similar calls in build() do expensive InheritedWidget traversal on every rebuild.
• Fix: Cache theme values in didChangeDependencies() — see Section 3.4 for the full pattern. For child widgets, pass pre-cached theme values from the parent:

// Parent passes cached values to children
CometChatImageBubble(
  imageUrl: message.attachment?.fileUrl,
  colorPalette: _colorPalette,  // Pre-cached from parent
  spacing: _spacing,            // Pre-cached from parent
);

7.2 Missing buildWhen optimization

• Symptom: Entire widget tree rebuilds on every BLoC state change, even when only a small part of the state changed.
• Cause: BlocConsumer or BlocBuilder without buildWhen — rebuilds on every state emission.
• Fix: Add buildWhen to limit rebuilds to relevant state changes:

BlocConsumer<MessageComposerBloc, MessageComposerState>(
  buildWhen: (previous, current) =>
      previous.isEditMode != current.isEditMode ||
      previous.isReplyMode != current.isReplyMode ||
      previous.isRecordingMode != current.isRecordingMode ||
      previous.editMessage != current.editMessage ||
      previous.replyMessage != current.replyMessage,
  listener: (context, state) { /* still receives ALL state changes */ },
  builder: (context, state) { /* only rebuilds when buildWhen is true */ },
)

7.3 O(n) lookups instead of O(1)

• Symptom: Slow scrolling in long message lists. findChildIndexCallback takes too long.
• Cause: Using list.indexWhere() (O(n)) to find messages instead of a Map-based O(1) lookup.
• Fix: Maintain a Map<int, int> alongside the message list for O(1) index lookups:

// In BLoC — maintain O(1) lookup map
final Map<int, int> _messageIndexMap = {};

int? findMessageIndex(int messageId) => _messageIndexMap[messageId];

// In SliverAnimatedList
SliverAnimatedList(
  findChildIndexCallback: (Key key) {
    if (key is ValueKey<int>) {
      final index = widget.findMessageIndex?.call(key.value) ??
          _messages.indexWhere((m) => m.id == key.value);
      if (index != -1) return visualPosition(index);
    }
    return null;
  },
)

8. Platform-Specific Issues

8.1 Android-specific

8.2 iOS-specific

8.3 Web-specific

// ✅ CORRECT — guard platform-specific code
import 'package:flutter/foundation.dart' show kIsWeb;

if (!kIsWeb) {
  // Native-only code (e.g., push notifications, file system access)
  setupPushNotifications();
}

// For conditional imports:
// lib/platform/native_service.dart — native implementation
// lib/platform/web_service.dart — web implementation

Quick Reference: Error → Fix Table

Checklist — Every CometChat Integration

Use this checklist to verify your integration is correct:

• CometChatUIKit.init() called and awaited before any usage
• Auth check uses CometChatUIKit.loggedInUser after init (not CometChat.getLoggedInUser())
• subscriptionType set in UIKitSettingsBuilder
• region is lowercase ('us', 'eu', 'in')
• Theme cached in didChangeDependencies(), not build()
• SDK listeners registered with unique ID, removed in dispose()
• Colors from CometChatThemeHelper, never hardcoded
• Strings from Translations.of(context), never hardcoded
• Android: minSdk ≥ 26, Jetifier enabled, ProGuard rules added
• iOS: permissions in Info.plist, deployment target ≥ 13.0
• Web: kIsWeb guards on platform-specific code

Source: cometchat/cometchat-uikit-flutter — distributed by TomeVault.