cometchat-flutter-v6-calls

Purpose

Production-grade voice + video calling for Flutter UIKit v6 (beta, Bloc-based). Loaded by cometchat-calls when framework === "flutter" and flutter_version === "v6". Operates in two modes:

• Standalone — calls is the product. Chat SDK + Calls SDK without the v6 UI Kit (rare today, since the UI Kit ships calling bundled). Custom call screens on the SDKs.
• Additive — calls layered onto an existing v6 chat integration. The v6 UI Kit ships call widgets in the same package (cometchat_chat_uikit) — no extra dependency. The skill enables calling on UIKitSettings, calls CometChatUIKitCalls.init() in the chat-init success callback, mounts the global incoming-call overlay at app root.

Read these other skills first:

• cometchat-calls — dispatcher (modes, hard rules, anti-patterns)
• cometchat-flutter-v6-core — UIKitSettings, init/login order (CHAT_INIT_BEFORE_CALLS_INIT is THE rule)
• cometchat-flutter-v6-events — Bloc event streams + listener registration

V6 vs V5 difference (critical for migration):

• V6 — single cometchat_chat_uikit package (calls bundled in)
• V5 — cometchat_chat_uikit + cometchat_calls_uikit (separate)
• V6 uses Bloc; V5 uses GetX
• V6 CometChatUIKitCalls.init(appId, region) must run AFTER CometChatUIKit.init() succeeds; V5 hides this via CometChatCallingExtension

Ground truth:

• SDK source — installed cometchat_chat_uikit@6.0.0-beta2 artifacts under ~/.pub-cache/
• Sample app — ~/Downloads/calls-sdk/calls-sdk-flutter-5/sample-apps/ (V5 sample; V6 sample app may not exist yet — verify before citing)
• Public docs — https://www.cometchat.com/docs/calls/flutter/overview (note: V6 docs may still reference V5 module split)

---

1. The seven hard rules — Flutter v6 specialization

1.0 Calls SDK login is its own step (v5+)

Same as v5 cohort — the v5 Calls SDK has its own auth state, separate from the Chat SDK. After CometChat.login succeeds, you MUST also call CometChatCalls.login — without it, the FIRST calls API call throws "auth token cannot be null".

V6's CometChatUIKitCalls.init() initializes the SDK but does not handle login. Login still needs to happen explicitly after the user signs in via CometChatUIKit.login:

import 'package:cometchat_sdk/cometchat_sdk.dart';
import 'package:cometchat_calls_sdk/cometchat_calls_sdk.dart';

// After CometChatUIKit.login resolves
CometChatCalls.login(
  uid: uid,
  authKey: AUTH_KEY,
  onSuccess: (User? callUser) { /* both ready */ },
  onError: (CometChatException e) { /* surface to user */ },
);

// Production:
CometChatCalls.loginWithAuthToken(
  authToken: tokenFromBackend,
  onSuccess: (User? user) { /* … */ },
  onError: (CometChatException e) { /* … */ },
);

Surprises:

• Chat SDK persists login via shared preferences. The Calls SDK does NOT — always check CometChatCalls.getLoggedInUser() on app start and re-login if it returns null.
• Even though V6 bundles the call UI into CometChatUIKit, the underlying Calls SDK login is still mandatory and separate.

1.1 Dual-SDK contract — CometChatUIKitCalls.init after CometChatUIKit.init

The V6 UI Kit unifies the two SDKs but init order is still load-bearing:

// ✓ RIGHT — calls init in chat init's onSuccess
CometChatUIKit.init(
  uiKitSettings: settings,
  onSuccess: (_) {
    CometChatUIKitCalls.init(appId, region,
      onSuccess: (_) => debugPrint('Calls SDK ready'),
      onError: (e) => debugPrint('Calls init failed: ${e.message}'),
    );
  },
);

// ✗ WRONG — parallel init causes "auth token null" intermittently
CometChatUIKit.init(uiKitSettings: settings);   // returns immediately
CometChatUIKitCalls.init(appId, region);         // race — chat auth not ready yet

CometChatUIKitCalls.init() must be called exactly once per app lifecycle. Re-calling it after logout + re-login causes "session already started" errors.

After logout: the calls SDK session is invalidated; on next login, call CometChatUIKitCalls.init() again. Treat this as a "first run" of the calls subsystem.

1.2 VoIP push — native_call_kit module + FCM + PushKit bridge

V6 ships a native_call_kit sub-module inside cometchat_chat_uikit that wraps CallKit (iOS) and ConnectionService (Android). The skill still wires:

• firebase_messaging — FCM data messages on Android
• iOS PushKit — same platform-channel bridge as v5 (Flutter has no first-party PushKit plugin)
• native_call_kit API — Dart-side handlers for incoming-call payloads → OS-level ring UI

In additive mode, opt-in. In standalone, mandatory.

1.3 Foreground service — same Android 14+ rules

⚠️ Android build prerequisite — Jetifier is mandatory. One of the cometchat_calls_uikit transitive deps still pulls in the legacy com.android.support:support-compat:26.1.0 AAR in V6. Without Jetifier, AGP fails with Duplicate class android.support.v4.* errors. Set in android/gradle.properties:

android.useAndroidX=true
android.enableJetifier=true

Flutter 3.x scaffolds omit enableJetifier=true by default — the build fails on first flutter build apk if you skip this.

Same as native Android / Flutter v5. The four FOREGROUND_SERVICE_* permissions plus MANAGE_OWN_CALLS / BIND_TELECOM_CONNECTION_SERVICE in android/app/src/main/AndroidManifest.xml. V6 raised Android minSdk to 26 (calls SDK in V6 raised the floor) — verify this is set in android/app/build.gradle.

1.4 Server-minted auth tokens

cometchat-flutter-v6-production covers it. CometChatUIKit.loginWithAuthToken(token) for production, never loginWithAuthKey(uid, authKey).

1.5 Hangup cleanup — Calls + ServiceLocator + native call UI

Future<void> endCall(String sessionId) async {
  await CometChatUIKitCalls.endSession();        // 1. end WebRTC + release tracks
  await FlutterCallkitIncoming.endAllCalls();    // 2. clear OS-level ring UI
  if (mounted) Navigator.of(context, rootNavigator: true).pop();  // 3. pop call screen
}

After CometChatUIKit.logout(), also reset the calls service locator:

CallOperationsServiceLocator.instance.reset();

The kit's call widgets handle the basic teardown automatically; custom WebRTC surfaces must replicate this.

1.6 Permissions — permission_handler + CallPermissions

V6 ships an internal CallPermissions helper that wraps the standard permission flow:

final granted = await CallPermissions.requestCallPermissions(callType: CallType.video);
if (!granted) { /* surface a clear UI message */ }

Native config (Info.plist + AndroidManifest) is identical to V5 (rule 1.6 in cometchat-flutter-v5-calls).

1.7 IncomingCall mounted at app root

V6 exposes the incoming-call overlay via CometChatDisplayIncomingCallOverlay mounted in MaterialApp's builder:

MaterialApp(
  navigatorKey: CallNavigationContext.navigatorKey,  // ⚠️ REQUIRED — see warning below
  builder: (context, child) {
    return Stack(
      children: [
        child!,
        const CometChatDisplayIncomingCallOverlay(),
      ],
    );
  },
);

⚠️ navigatorKey: CallNavigationContext.navigatorKey is REQUIRED on MaterialApp at v6.0.0-beta2. The kit's CometChatCallButtons and outgoing-call flow navigate via CallNavigationContext.navigatorKey.currentContext. Without this line, CometChat.initiateCall succeeds but the outgoing-call screen never renders — kit logs "Context is not mounted for navigation" and silently drops the navigation. Symptom: user taps call button, peer rings, but the Flutter app shows nothing.

Import: import 'package:cometchat_chat_uikit/cometchat_calls_uikit.dart' show CallNavigationContext; (use show to avoid a name collision with kit-exported IncomingCallOverlay).

⚠️ Outgoing → in-call screen transition is broken at v6.0.0-beta2. When the peer accepts, the call's status moves to ongoing at the server level — but the kit's outgoing-call screen does NOT transition to the in-call view. Users see the "Calling…" ring spinner indefinitely while the call is actually live. Pressing the reject button fires CometChat.rejectCall which the server rejects with "The call status cannot be updated from ongoing to cancelled". No client-side workaround known — vendor needs to fix the outgoing-call BLoC's onOutgoingCallAccepted handler to push the in-call route. Validated on 2026-05-13 against a Next.js web peer.

In standalone mode, native_call_kit owns the OS-level ring UI; the in-app overlay only fires when the app is foregrounded.

---

2. Setup

# pubspec.yaml
dependencies:
  flutter:
    sdk: flutter
  cometchat_chat_uikit: ^6.0.0-beta2     # calls bundled in
  permission_handler: ^11.0.0
  flutter_callkit_incoming: ^2.0.0       # standalone — VoIP UI bridge
  firebase_messaging: ^14.0.0            # standalone — Android FCM
  firebase_core: ^2.0.0

If pub.dev resolution lags, use the Cloudsmith hosted pin:

  cometchat_chat_uikit:
    hosted: https://dart.cloudsmith.io/cometchat/cometchat/
    version: ^6.0.0-beta2

Init (additive mode):

import 'package:cometchat_chat_uikit/cometchat_chat_uikit.dart';
import 'package:cometchat_chat_uikit/cometchat_calls_uikit.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  final settings = (UIKitSettings.builder()
    ..appId = CometChatConfig.appId
    ..region = CometChatConfig.region
    ..authKey = CometChatConfig.authKey
    ..subscriptionType = CometChatSubscriptionType.allUsers)
    .build();

  CometChatUIKit.init(
    uiKitSettings: settings,
    onSuccess: (_) {
      CometChatUIKitCalls.init(
        CometChatConfig.appId,
        CometChatConfig.region,
        onSuccess: (_) => runApp(const MyApp()),
        onError: (e) => runApp(MyErrorApp(e.message)),
      );
    },
    onError: (e) => runApp(MyErrorApp(e.message)),
  );
}

The first import gives you chat components. The second gives you call-specific types.

---

3. Components catalog (V6 widgets — Bloc-driven)

Architecture (lives inside cometchat_chat_uikit):

call_ui/src/
├── call_buttons/          # CometChatCallButtons + CallButtonsBloc
├── incoming_call/         # CometChatIncomingCall + IncomingCallBloc
├── outgoing_call/         # CometChatOutgoingCall + OutgoingCallBloc
├── ongoing_call/          # CometChatOngoingCall + OngoingCallBloc
├── call_logs/             # CometChatCallLogs + CallLogsBloc + Clean Architecture
├── call_operations/       # Shared DI / use cases / repositories (CallOperationsServiceLocator)
├── call_bubble/           # CometChatCallBubble — call-event bubble in message list (auto-rendered)
├── call_settings/         # CometChatUIKitCalls, CallNavigationContext
├── native_call_kit/       # iOS CallKit / Android ConnectionService bridge
├── utils/                 # CallUtils, CallStateService, CallPermissions
├── call_event_service.dart  # Centralized call event handling
└── calling_configuration.dart  # Top-level config object

Component reference

Widget	Purpose	Notes
CometChatCallButtons(user:, group:)	Voice + video buttons	Mutually exclusive user / group. Use group: for group calls (meetings).
CometChatIncomingCall(call:, user:, onAccept:, onDecline:)	In-app foreground ring UI	onAccept/onDecline are (BuildContext, Call) -> void. Custom view slots: titleView, subTitleView, leadingView, trailingView.
CometChatOutgoingCall(call:, user:, outgoingCallStyle:)	Dialing UI	Auto-mounted when initiateCall is called via the kit.
CometChatOngoingCall(callSettingsBuilder:, sessionId:, callWorkFlow:)	Active call view	callWorkFlow: CallWorkFlow.directCalling or CallWorkFlow.defaultCalling. Set resizeToAvoidBottomInset: false on host Scaffold.
CometChatCallLogs(onItemClick:, callLogsStyle:)	Paginated history	Clean Architecture + BLoC; CallLogsServiceLocator is initialized automatically when the widget mounts.
CometChatCallBubble	Call-event message bubble	Auto-rendered for call-type messages in CometChatMessageList.

CometChatUIKitCalls API

Method	Purpose
CometChatUIKitCalls.init(appId, region)	Initialize calls SDK (after chat init — rule 1.1)
CometChatUIKitCalls.initiateCall(call)	Start a call (Chat SDK initiate + Calls SDK preflight)
CometChatUIKitCalls.acceptCall(sessionId)	Accept incoming
CometChatUIKitCalls.rejectCall(sessionId, status)	Reject / cancel
CometChatUIKitCalls.generateToken(sessionId)	Mint session-scoped RTC token
CometChatUIKitCalls.startSession(sessionId, settings)	Start WebRTC
CometChatUIKitCalls.endSession()	End and cleanup

CallingConfiguration — top-level config

CallingConfiguration(
  outgoingCallConfiguration: CometChatOutgoingCallConfiguration(...),
  incomingCallConfiguration: CometChatIncomingCallConfiguration(...),
  callButtonsConfiguration: CallButtonsConfiguration(...),
  groupSessionSettingsBuilder: sessionSettingsBuilder,
)

Pass to UIKitSettings.callingConfiguration to apply globally without per-component plumbing.

Bloc events (when interacting directly — UIKit widgets handle these for you)

Bloc	Events
CallButtonsBloc	InitiateVoiceCall, InitiateVideoCall
IncomingCallBloc	AcceptCall, RejectCall
OutgoingCallBloc	CancelCall, CallAccepted(call), CallRejected(call)
OngoingCallBloc	StartSession(sessionId, settings), EndSession
CallLogsBloc	LoadCallLogs, LoadMoreCallLogs

CallOperationsServiceLocator must be initialized before using call BLoCs directly — UIKit widgets handle this automatically. After logout, call CallOperationsServiceLocator.instance.reset() to clean up.

---

4. Standalone integration

When product === "voice-video" and there is no v6 chat integration.

Split by calling mode:

4a. Standalone — Session mode (meeting-room UX, no ringing)

Calls SDK ONLY. NO Chat SDK, NO UIKit. Same SDK as v5 (cometchat_calls_sdk). Scaffold:

1. pubspec.yaml — cometchat_calls_sdk: ^5.0.0 + flutter_bloc + equatable + permission_handler ONLY.
2. lib/main.dart — CometChatCalls.init(appId, region, authKey). Permission requests. NO Chat SDK init.
3. lib/cubits/call_session_cubit.dart — Cubit implements SessionStatusListeners. CometChatCalls.joinSession(sessionId:, sessionSettings: SessionSettingsBuilder().build(), onSuccess:, onError:). Renders the returned Widget? via SizedBox.expand. See references/call-session.md.
4. lib/screens/call_room.dart — BlocConsumer for auto-pop on idle transition.
5. Native config — Camera + microphone permissions only.

Why no Chat SDK / no UIKit: session mode never touches a Chat SDK call entity. No ringing, no UIKit incoming-call overlay needed.

4b. Standalone — Ringing mode (kit overlay + CallKit + FCM)

Dual-SDK + UIKit. Scaffold:

1. lib/main.dart — Chat SDK + Calls SDK init (no UIKit), permission requests, flutter_callkit_incoming + Firebase setup.
2. lib/services/voip_service.dart — FCM + PushKit + native_call_kit bridge.
3. lib/widgets/call_button.dart — Voice + video buttons next to a contact.
4. lib/screens/ongoing_call_screen.dart — CometChatCalls.joinSession(sessionId:, sessionSettings:, onSuccess:, onError:) with Widget rendered via SizedBox.expand. Cubit-driven state.
5. lib/screens/call_logs_screen.dart — /calls route.
6. MaterialApp.builder — CometChatDisplayIncomingCallOverlay for foreground rings (rule 1.7).
7. Native config — same as V5 standalone (Info.plist + AndroidManifest + Firebase config files).

5. Additive integration

When chat is already integrated. The skill:

1. Confirms cometchat_chat_uikit is on ^6.0.0-beta2 — calls are already bundled.
2. Patches the CometChatUIKit.init call to add CometChatUIKitCalls.init in the success callback (rule 1.1).
3. Adds CometChatDisplayIncomingCallOverlay to MaterialApp.builder (rule 1.7).
4. Confirms CometChatMessageHeader shows call buttons by default (hideVoiceCallButton: false, hideVideoCallButton: false).
5. Optionally adds CometChatCallLogs as a tab/screen.
6. VoIP push: opt-in.

6. Anti-patterns

1. Init Calls SDK before Chat SDK. Auth-token race; CometChatUIKitCalls.init must run inside CometChatUIKit.init's onSuccess. Rule 1.1.
2. Calling CometChatUIKitCalls.init more than once per app lifecycle. Causes "session already started". After logout-relogin, this is the first run again — but in a single session, do it exactly once.
3. Per-screen incoming-call handling. CometChatIncomingCall(call: c, user: u) mounted on the messages screen only fires there. Mount the overlay at app root via MaterialApp.builder (rule 1.7).
4. Forgetting resizeToAvoidBottomInset: false on Scaffolds with call UI — keyboard show breaks WebRTC layout.
5. Group calls with user: instead of group: on CometChatCallButtons. Group calls require group:; the widget silently mismatches if both are passed.
6. Caching the theme in build() instead of didChangeDependencies(). Listed in V6 components catalog as a perf rule but applies to every call surface.
7. Skipping CallOperationsServiceLocator.instance.reset() after logout. Stale singletons leak across user sessions; calls subsystem behaves erratically on next login.
8. Mixing V5 and V6 widget imports. V5's cometchat_calls_uikit namespace and V6's cometchat_chat_uikit/cometchat_calls_uikit.dart barrel re-export different classes with the same name. Pick a cohort and stay there.

7. Verification checklist

Static:

• cometchat_chat_uikit ^6.0.0-beta2 in pubspec.yaml (V6 bundles calls — no separate calls package)
• CometChatUIKitCalls.init called inside CometChatUIKit.init's onSuccess (rule 1.1)
• CometChatUIKitCalls.init called exactly once per app lifecycle
• CometChatDisplayIncomingCallOverlay mounted in MaterialApp.builder (rule 1.7)
• iOS Info.plist: NSCameraUsageDescription + NSMicrophoneUsageDescription + UIBackgroundModes (audio + voip + remote-notification)
• Android minSdk = 26, ProGuard rules -keep class com.cometchat.** { *; }
• Android manifest: four FOREGROUND_SERVICE_* permissions + MANAGE_OWN_CALLS + BIND_TELECOM_CONNECTION_SERVICE
• Hangup path: endSession + FlutterCallkitIncoming.endAllCalls + Navigator pop
• After logout: CallOperationsServiceLocator.instance.reset()
• resizeToAvoidBottomInset: false on call-screen Scaffolds
• Theme cached in didChangeDependencies(), not build()
• Standalone only: flutter_callkit_incoming + firebase_messaging + iOS PushKit platform-channel bridge

Runtime (real devices, both platforms):

• iOS — terminated app, lock-screen rings on incoming call (CallKit)
• Android — terminated app, heads-up notification rings (ConnectionService)
• Both — outgoing call connects, two-way audio + video
• Both — hangup releases camera + mic, no system call UI stuck
• Logout + relogin: calls subsystem reinitializes cleanly (no "session already started")
• Android 14+: ongoing-call notification visible, swipe-up doesn't kill the call
• Keyboard during call doesn't break layout

8. Pointers

• cometchat-calls — dispatcher
• cometchat-flutter-v6-core — UIKitSettings, init/login order, init guard rules
• cometchat-flutter-v6-events — Bloc event streams
• cometchat-flutter-v6-features — feature catalog (calls is a base capability — features layer on top)
• cometchat-flutter-v6-production — server-minted tokens, ProGuard, environment config
• cometchat-flutter-v6-troubleshooting — pubspec resolution, Bloc errors, theme cache, build errors
• cometchat-flutter-v6-migration — V5 → V6 migration recipes (GetX → Bloc, calls package → bundled, theme API rewrite)

Known external SDK gotchas (worth surfacing in any agent message)

• startSession on Android can return null with a 5-second timeout and no error feedback — known platform issue; retry once before surfacing failure.
• SessionType.audio is ignored on Android in some V6 SDK builds — always opens with video. External SDK bug; track upstream.