why am I meeting this erroor ? flutter: Connection error: LiveKit Exception: [TrackCreateException] Failed to create stream, at least 1 video or audio track should exist import 'dart:convert'; import 'package:flutter/material.dart'; import 'package:http/http.dart' as http; import 'package:livekit_client/livekit_client.dart'; import 'package:permission_handler/permission_handler.dart'; void main() { runApp(MaterialApp(home: LiveKitVideoCanvasApp())); } class LiveKitTokenResponse { final String accessToken; const LiveKitTokenResponse({required this.accessToken}); factory LiveKitTokenResponse.fromJson(Map<String, dynamic> json) { return LiveKitTokenResponse(accessToken: json['accessToken'] as String); } } class LiveKitVideoCanvasApp extends StatefulWidget { const LiveKitVideoCanvasApp({Key? key}) : super(key: key); @override _LiveKitVideoCanvasAppState createState() => _LiveKitVideoCanvasAppState(); } class _LiveKitCanvasPainter extends CustomPainter { @override void paint(Canvas canvas, Size size) { final paint = Paint() ..color = Colors.blue.withOpacity(0.3) ..style = PaintingStyle.fill; canvas.drawRect(Offset.zero & size, paint); final circlePaint = Paint() ..color = Colors.white.withOpacity(0.5) ..style = PaintingStyle.fill; canvas.drawCircle(Offset(size.width / 2, size.height / 2), 50, circlePaint); } @override bool shouldRepaint(covariant CustomPainter oldDelegate) => false; } class _LiveKitVideoCanvasAppState extends State<LiveKitVideoCanvasApp> { Room? _room; LocalVideoTrack? _localVideoTrack; bool _isConnected = false; CustomPaint? _customCanvas; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar(title: const Text('LiveKit Video with Canvas')), body: Column( children: [ // Video and Canvas View _isConnected ? SizedBox( width: 300, height: 400, child: _customCanvas ?? Container(child: Text("Connection in progress")), ) : const Center(child: Text('Not Connected')), // Connect Button ElevatedButton( onPressed: _isConnected ? null : _connectToRoom, child: const Text('Connect to Room'), ), ], ), ); } @override void dispose() { _room?.disconnect(); _localVideoTrack?.dispose(); super.dispose(); } Future<String> getLivekitToken() async { try { http.Response response = await http.get( Uri.parse( "https://example.ngrok-free.app/api/livekit-token", ), headers: {"ngrok-skip-browser-warning": "true"}, ); if (response.statusCode == 200) { LiveKitTokenResponse liveKitTokenResponse = LiveKitTokenResponse.fromJson( jsonDecode(response.body) as Map<String, dynamic>, ); return liveKitTokenResponse.accessToken; } else { throw Exception('Failed to get LiveKit token'); } } catch (e) { print('Token retrieval error: $e'); rethrow; } } @override void initState() { super.initState(); _initializeLiveKit(); } Future<void> _connectToRoom() async { try { // Ensure video track exists _localVideoTrack ??= await LocalVideoTrack.createCameraTrack(); // Create room if not exists _room ??= Room(); // Get LiveKit token String livekitToken = await getLivekitToken(); // Connect to room await _room!.prepareConnection( 'wss://example.livekit.cloud', livekitToken, ); await _room!.connect( 'wss://example.livekit.cloud', livekitToken, roomOptions: const RoomOptions(adaptiveStream: true, dynacast: true), ); // Publish local video track await _room!.localParticipant?.publishVideoTrack(_localVideoTrack!); setState(() { _isConnected = true; _customCanvas = CustomPaint( painter: _LiveKitCanvasPainter(), child: VideoTrackRenderer(_localVideoTrack!), ); }); } catch (error) { print('Connection error: $error'); ScaffoldMessenger.of( context, ).showSnackBar(SnackBar(content: Text('Connection failed: $error'))); } } Future<void> _initializeLiveKit() async { // Request camera and microphone permissions final cameraStatus = await Permission.camera.request(); final micStatus = await Permission.microphone.request(); if (cameraStatus.isGranted && micStatus.isGranted) { try { // Create video track immediately _localVideoTrack = await LocalVideoTrack.createCameraTrack(); } catch (e) { print('Failed to create video track: $e'); } } } }

Thanks for reaching out, NDIZIHIWE. I'm an AI assistant and I'm here to help. Give me a moment while I research this topic.

any sample code snippet ?

Unfortunately, I couldn't locate a specific code snippet for creating video or audio tracks in the LiveKit Flutter SDK. However, based on your existing code, you are already using

LocalVideoTrack.createCameraTrack()

to create a video track. Here's a simplified example:

import 'package:livekit_client/livekit_client.dart';

Future<void> createVideoTrack() async {
  try {
    // Request camera and microphone permissions
    final cameraStatus = await Permission.camera.request();
    final micStatus = await Permission.microphone.request();

    if (cameraStatus.isGranted && micStatus.isGranted) {
      // Create a local video track
      LocalVideoTrack localVideoTrack = await LocalVideoTrack.createCameraTrack();
      print('Video track created successfully: $localVideoTrack');
    } else {
      print('Permissions not granted for camera or microphone.');
    }
  } catch (e) {
    print('Error creating video track: $e');
  }
}

Ensure that you call this function after requesting the necessary permissions. Let me know if you need further clarification or additional help!