CometChat Calls integration for Flutter UIKit v6 (Bloc-based, stable). Production-ready at v6.0.1 GA (validated 2026-05-27 on Pixel 3) with ONE explicit MaterialApp wiring requirement still active from v6.0.0-beta2 — MaterialApp MUST wire navigatorKey to CallNavigationContext.navigatorKey or the outgoing-call screen never renders. (Vendor's own 6.0.1 sample is missing this line and broken out-of-the-box — file a vendor ticket if you find that sample first.) The earlier outgoing-to-in-call BLoC transition bug from beta2 is FIXED in 6.0.1 GA per the v6.0.0 changelog's 'Refreshed BLoC implementations across ongoing call flows' entry. Customers can now use V6 for calls. Covers UIKitSettings calling block, CometChatUIKitCalls.init() after CometChatUIKit.init() (CALLS_INIT_AFTER_CHAT_INIT), the kit's Bloc-driven CometChatCallButtons / CometChatIncomingCall / CometChatOutgoingCall / CometChatOngoingCall / CometChatCallLogs / CometChatCallBubble widgets, CallingConfiguration, CallOperationsServiceLocator lifecycle, V
CometChat Calls integration for Flutter UIKit v6 (Bloc-based, stable). Production-ready at v6.0.1 GA (validated 2026-05-27 on Pixel 3) with ONE explicit MaterialApp wiring requirement still active from v6.0.0-beta2 — MaterialApp MUST wire navigatorKey to CallNavigationContext.navigatorKey or the outgoing-call screen never renders. (Vendor's own 6.0.1 sample is missing this line and broken out-of-the-box — file a vendor ticket if you find that sample first.) The earlier outgoing-to-in-call BLoC transition bug from beta2 is FIXED in 6.0.1 GA per the v6.0.0 changelog's 'Refreshed BLoC implementations across ongoing call flows' entry. Customers can now use V6 for calls. Covers UIKitSettings calling block, CometChatUIKitCalls.init() after CometChatUIKit.init() (CALLS_INIT_AFTER_CHAT_INIT), the kit's Bloc-driven CometChatCallButtons / CometChatIncomingCall / CometChatOutgoingCall / CometChatOngoingCall / CometChatCallLogs / CometChatCallBubble widgets, CallingConfiguration, CallOperationsServiceLocator lifecycle, VoIP push via external packages (FCM + PushKit + flutter_callkit_incoming — there is NO bundled native_call_kit module in the kit), and additive-vs-standalone modes.
Production-grade voice + video calling for Flutter UIKit v6 (stable, 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)
Single source of truth, verified against installed source on 2026-06-01: when you set on AND use / (i.e. the V6 UIKit shape, the recommended path), — once Chat SDK login resolves, the kit hands the auth token to the Calls SDK and brings it online. You do NOT need to call yourself. See lines 87-197 in the installed package.
cometchat_chat_uikit-6.0.1
..enableCalls = true
UIKitSettingsBuilder
CometChatUIKit.init
login
the kit's CallEventService calls CometChatCalls.init() AND CometChatCalls.loginWithAuthToken(...) for you internally
CometChatCalls.login
lib/call_ui/src/call_event_service.dart
The earlier version of this skill said "Same as v5 cohort — you MUST also call CometChatCalls.login." That's wrong for V6 UIKit usage. It IS correct only when the integration is raw SDK (no UIKit) — i.e. the developer imported cometchat_calls_sdk directly without going through CometChatUIKit. Most integrations don't.
The V6 UIKit recipe (recommended — 99% of integrations):
final settings = (UIKitSettingsBuilder()
..subscriptionType = CometChatSubscriptionType.allUsers
..region = REGION
..appId = APP_ID
..authKey = AUTH_KEY
..enableCalls = true) // <-- this flag wires CallEventService
.build();
CometChatUIKit.init(
uiKitSettings: settings,
onSuccess: (_) async {
await CometChatUIKit.login(uid); // kit logs Chat SDK
// Calls SDK login fires INTERNALLY here via CallEventService.
// No manual CometChatCalls.login needed.
},
onError: (e) { /* surface */ },
);
Raw-SDK fallback (only if NOT using CometChatUIKit):
// You should rarely need this in V6 — only when you've opted out of the UIKit
// entirely and are wiring chat-sdk + calls-sdk by hand.
import 'package:cometchat_calls_sdk/cometchat_calls_sdk.dart';
// Chat SDK login is POSITIONAL (cometchat.dart:843 — login(String uid, String authKey, {onSuccess, onError}))
await CometChat.login(uid, AUTH_KEY, onSuccess: (User u) {}, onError: (CometChatException e) {});
// Calls SDK login uses NAMED params; onError is CometChatCallsException (cometchatcalls.dart:224-228)
CometChatCalls.login(
uid: uid,
authKey: AUTH_KEY,
onSuccess: (User? callUser) { /* both ready */ },
onError: (CometChatCallsException e) { /* surface */ },
);
Surprises:
The kit waits to log the Calls SDK in until Chat SDK login resolves; this is internal — your code only awaits Chat SDK login.
If you set enableCalls = true but Chat-SDK login never fires (init error, network), call buttons silently render but the internal CometChatCalls.startSession flow throws "auth token cannot be null" (there is no startCall method — the lifecycle is startSession/joinSession). The fix is to surface the Chat SDK login error, not to add a manual CometChatCalls.login.
Cross-reference: references/add-calls-to-existing-chat.md (additive-mode recipe) shows the same canonical pattern.
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:
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 — external packages (FCM + CallKit/PushKit bridge)
There is NO bundled native_call_kit module in cometchat_chat_uikit v6. (Verified against the published cometchat_chat_uikit 6.0.1 source — no native_call_kit directory, and no flutter_callkit_incoming / CallKit / ConnectionService dependency in its pubspec.yaml.) VoIP push is wired with the SAME external packages the v5 family uses — the kit does not provide an OS-ring-UI module of its own.
Wire VoIP push with:
firebase_messaging — FCM data messages on Android (and iOS data path)
flutter_callkit_incoming — cross-platform OS-level incoming-call ring UI (iOS CallKit + Android ConnectionService); you add this package yourself
iOS PushKit — platform-channel bridge for VoIP pushes (Flutter has no first-party PushKit plugin) — same approach as v5
The Dart-side handler decodes the incoming-call payload from FCM/PushKit, shows the ring UI via flutter_callkit_incoming, and on accept routes into the kit's call surface. In additive mode this is opt-in; in standalone, mandatory.
1.3 Foreground service — same Android 14+ rules
⚠️ Android build prerequisite — Jetifier is mandatory. In V6 calls are bundled in cometchat_chat_uikit (there is no separate cometchat_calls_uikit package); one of its transitive deps still pulls in the legacy com.android.support:support-compat:26.1.0 AAR. Without Jetifier, AGP fails with Duplicate class android.support.v4.* errors. Set in android/gradle.properties:
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).
V6 ships an internal CallPermissions helper that wraps the standard permission flow:
final granted = await CallPermissions.requestMicrophoneAndCamera(); // video; use requestMicrophone() for audio-only
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 — automatic when enableCalls = true (ENG-35698)
Canonical truth from cometchat_chat_uikit-6.0.1: the kit's CallEventService automatically calls IncomingCallOverlay.show(...) from lib/call_ui/src/incoming_call/cometchat_display_incoming_call_overlay.dart whenever a foreground incoming call fires AND enableCalls = true is set on UIKitSettingsBuilder. You do NOT mount the overlay yourself. There is NO CometChatDisplayIncomingCallOverlay widget — that was a fictional class name from earlier drafts. The real class is IncomingCallOverlay (in cometchat_display_incoming_call_overlay.dart) and it's an imperative singleton (.show(...) / .dismiss()).
The correct V6 wiring is just the navigatorKey:
MaterialApp(
navigatorKey: CallNavigationContext.navigatorKey, // ⚠️ REQUIRED — see warning below
home: const AppRoot(), // your existing root
);
That's it. No Stack, no builder wrapper, no mounting of an "overlay widget" — once enableCalls = true is in your UIKitSettingsBuilder, the kit's CallEventService shows + dismisses IncomingCallOverlay for you when foreground rings happen.
⚠️ navigatorKey: CallNavigationContext.navigatorKey is REQUIRED on MaterialApp — still active in v6.0.1 GA. The kit's CometChatCallButtons and outgoing-call flow navigate via CallNavigationContext.navigatorKey.currentContext. Without this line, CometChat.initiateCall succeeds (CALL-TRAP confirms onSuccess fires with a valid sessionId) but currentContext is null so CometChatOutgoingCall never mounts. Symptom: user taps call button, peer rings, but the Flutter app shows nothing. Note: the vendor's own 6.0.1 sample app (examples/sample_app) is broken for calls on mobile out-of-the-box — its main.dart sets navigatorKey: kIsWeb ? CallNavigationContext.navigatorKey : null, i.e. it wires the key only on web and passes null on Android/iOS, so the outgoing-call screen never mounts on a device (validated on Pixel 3). The kit's other sample (examples/ai_sample_app) sets it unconditionally (navigatorKey: navigatorKey + CallNavigationContext.navigatorKey = navigatorKey) — that is the correct, device-safe form this skill prescribes. Wire navigatorKey: CallNavigationContext.navigatorKey unconditionally (do NOT gate it on kIsWeb like sample_app does); don't copy sample_app's main.dart verbatim.
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 FIXED in v6.0.1 GA. (It was broken in v6.0.0-beta2 — the outgoing-call screen stayed on "Calling…" indefinitely after the peer accepted.) Validated end-to-end 2026-05-27 on Pixel 3 with full CALL-TRAP instrumentation: with the navigatorKey wired (above), when the peer accepts, the kit's OutgoingCallBloc swaps the outgoing screen for the in-call surface automatically (via the kit's internal call-overlay — CallScreenOverlay.show()), transitioning from CometChatOutgoingCall ("Calling…") to the in-call view — observed call-duration timer ticking + WebRTC rendering frames @ ~27 fps. The v6.0.0 changelog's "Refreshed BLoC implementations across … call buttons, and ongoing call flows" was the fix. No client-side workaround needed beyond the navigatorKey wiring.
In standalone mode, flutter_callkit_incoming (the external package you add) owns the OS-level ring UI; the kit's in-app overlay only fires when the app is foregrounded.
V6 GA is on pub.dev — use the plain dependency above, NOT a Cloudsmith hosted: stanza. Cloudsmith (dart.cloudsmith.io/cometchat/cometchat/) only hosts the pre-GA 6.0.0-beta* builds, so a hosted: install of ^6.0.x fails with "version solving failed". The GA range resolves 6.0.1/6.0.2/6.0.3 from pub.dev. (Cloudsmith is only for the legacy V5 packages.)
Param is sessionSettingsBuilder: NOT callSettingsBuilder: (verified lib/call_ui/src/ongoing_call/cometchat_ongoing_call.dart constructor). 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)
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.
Telemetry attribution (ai-agent). Session mode (§4a, Calls SDK only) MUST init via CometChatCalls.initFromSettings(onSuccess:, onError:) (cometchat_calls_sdk >= 5.0.4, verified against lib/src/plugin/cometchatcalls.dart) reading the cometchat-settings.json asset — the only reporter in a calls-only app; fires on CometChatCalls.login. Additive mode: no calling-enable field is needed — integrationSource = "ai-agent" is persisted (appId-scoped) by the chat-side CometChatUIKit.initFromSettings (cometchat-flutter-v6-core), and the calls integration is attributed at the backend from the calls SDK version + platform present in the /user_sessions node. Enabling calls via ..enableCalls = true + CometChatUIKitCalls.init() does not affect either signal.
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:
pubspec.yaml — cometchat_calls_sdk: ^5.0.4 (the floor that ships initFromSettings) + flutter_bloc + equatable + permission_handler. Declare cometchat-settings.json under flutter: assets:.
lib/main.dart — CometChatCalls.initFromSettings(onSuccess: ..., onError: ...) reading the committed cometchat-settings.json asset so the calls-only app self-reports integrationSource = "ai-agent" (cometchat_calls_sdk >= 5.0.4, verified against src/plugin/cometchatcalls.dart; on <= 5.0.3 fall back to CometChatCalls.init((CallAppSettingBuilder()..appId = APP_ID..region = REGION).build(), onSuccess:, onError:) — CallAppSettingBuilder exposes only appId/region/host overrides, no authKey). Permission requests. NO Chat SDK init. The report fires on CometChatCalls.login success.
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.
lib/screens/call_room.dart — BlocConsumer for auto-pop on idle transition.
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.
lib/services/voip_service.dart — FCM + PushKit + flutter_callkit_incoming bridge (you write this; the kit ships no VoIP/ring-UI module).
lib/widgets/call_button.dart — Voice + video buttons next to a contact.
lib/screens/ongoing_call_screen.dart — CometChatCalls.joinSession(sessionId:, sessionSettings:, onSuccess:, onError:) with Widget rendered via SizedBox.expand. Cubit-driven state.
lib/screens/call_logs_screen.dart — /calls route.
MaterialApp — navigatorKey: CallNavigationContext.navigatorKey wired; enableCalls = true on UIKitSettingsBuilder shows the foreground overlay automatically (rule 1.7). No widget mount needed.
Native config — same as V5 standalone (Info.plist + AndroidManifest + Firebase config files).
5. Additive integration
When chat is already integrated. The skill:
Confirms cometchat_chat_uikit is on ^6.0.1 — calls are already bundled.
Patches the CometChatUIKit.init call to add CometChatUIKitCalls.init in the success callback (rule 1.1).
Confirms ..enableCalls = true is set on UIKitSettingsBuilder (rule 1.0) so foreground overlay fires automatically; ensures navigatorKey: CallNavigationContext.navigatorKey is on MaterialApp (rule 1.7).
Optionally adds CometChatCallLogs as a tab/screen.
VoIP push: opt-in.
6. Anti-patterns
Init Calls SDK before Chat SDK. Auth-token race; CometChatUIKitCalls.init must run inside CometChatUIKit.init's onSuccess. Rule 1.1.
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.
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).
Forgetting resizeToAvoidBottomInset: false on Scaffolds with call UI — keyboard show breaks WebRTC layout.
Group calls with user: instead of group: on CometChatCallButtons. Group calls require group:; the widget silently mismatches if both are passed.
Caching the theme in build() instead of didChangeDependencies(). Listed in V6 components catalog as a perf rule but applies to every call surface.
Skipping CallOperationsServiceLocator.instance.reset() after logout. Stale singletons leak across user sessions; calls subsystem behaves erratically on next login.
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 ^6.0.1 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
..enableCalls = true on UIKitSettingsBuilder + navigatorKey: CallNavigationContext.navigatorKey on MaterialApp (rule 1.7) — no manual overlay widget mount
No reference to CometChatDisplayIncomingCallOverlay (fictional class — does NOT exist; ENG-35698)
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 — field-observed on Pixel 3, not confirmed in the SDK source; retry once before surfacing failure. (Audio vs video is driven by the Chat-SDK Call.type string — there is no SessionType enum in the calls SDK.)
Audio-only calls have been observed opening with video on Android in some builds (field-observed; verify against your installed SDK version) — set the call type explicitly via the Chat-SDK Call(type: "audio") and confirm the rendered surface.
