flutter-macos-permission-handler-camera-failure

Flutter macOS permission_handler Camera Failure

Problem

Camera/microphone permission checks using the permission_handler Flutter plugin throw exceptions on macOS desktop, causing permission gates to emit error states. The camera screen never renders, but the user sees a placeholder UI with no clear error message.

Context / Trigger Conditions

Use this skill when:

• Flutter app works on iOS/Android but camera fails on macOS
• Permission gate shows loading or error state on macOS
• Logs show CameraPermissionError state being emitted
• Permission.camera.status or Permission.microphone.status throws exceptions
• Camera placeholder UI appears but VideoRecorderScreen (or equivalent) never initializes
• No camera-related logs appear after navigation to camera screen

Key diagnostic pattern:

🔐 CameraPermissionGate initState
🔐 Building with state: CameraPermissionInitial
🔐 Triggering permission refresh
🔐 Permission state changed: CameraPermissionError  <-- This is the tell

Root Cause

The permission_handler plugin uses platform channels that don't work reliably on macOS desktop. When checkCameraStatus() or checkMicrophoneStatus() is called:

• On iOS/Android: Returns proper permission status
• On macOS: Throws exception → BLoC catches → Emits error state → Screen blocked

macOS handles camera/microphone permissions at the system level - the first time an app tries to access the camera, macOS shows its own permission dialog.

Solution

Bypass permission_handler on macOS and assume permissions are authorized:

Future<void> _onRefresh(
  CameraPermissionRefresh event,
  Emitter<CameraPermissionState> emit,
) async {
  // On macOS desktop, permission_handler doesn't work reliably.
  // macOS handles camera permissions at the system level when the app
  // actually tries to access the camera, showing its own permission dialog.
  if (!kIsWeb && Platform.isMacOS) {
    emit(const CameraPermissionLoaded(CameraPermissionStatus.authorized));
    return;
  }

  // Normal permission check for iOS/Android
  try {
    final status = await checkPermissions();
    emit(CameraPermissionLoaded(status));
  } catch (e) {
    emit(const CameraPermissionError());
  }
}