Initialization

To create a VWO Client instance, you need to initialize the VWO FME Flutter SDK. This client instance serves as the core interface for conducting feature management and experimentation(A/B and personalization) within your application.

Usage

import 'package:vwo_fme_flutter_sdk/vwo.dart';
import 'package:vwo_fme_flutter_sdk/vwo/models/vwo_init_options.dart';
import 'package:vwo_fme_flutter_sdk/vwo/models/vwo_user_context.dart';
import 'package:vwo_fme_flutter_sdk/vwo/models/get_flag.dart';
import 'package:vwo_fme_flutter_sdk/logger/log_transport.dart';

// Create a VWOInitOptions object
final vwoInitOptions = VWOInitOptions(
  sdkKey: 'your-sdk-key',
  accountId: 12345
);

// Initialize the SDK
final vwoClient = await VWO.init(vwoInitOptions);

The init() method is called with the sdkKey and accountId. It initializes and returns a VWO Client Object vwoClient, which can be used to perform feature management and experimentation tasks. This client object allows you to run experiments, track events, and enable/disable feature flags.

Parameter Definitions

Parameter	Type	Description
accountId Required	Integer	Your VWO application's Account ID.
sdkKey Required	String	A unique environment key provided to you inside the Websites & Apps section in the VWO application, under Default Project.
pollInterval Optional	Integer	Time (in milliseconds) at which VWO should check with the server for any updates to the feature flag or rules in the VWO Dashboard. Useful to keep your VWO Client instance up-to-date with any changes made in the VWO Application. For more details, please check -Polling
cachedSettingsExpiryTime Optional	Integer	Controls the duration (in milliseconds) the SDK uses cached settings before fetching new ones.
batchMinSize Optional	Integer	Minimum number of events to trigger a batch upload.
batchUploadTimeInterval Optional	Integer	Time interval (in milliseconds) for periodic batch uploads.
logger Optional	Object	An optional logger object that defines the logging behavior. For more details, please check - Logger
integrations Optional	Object	A callback function that receives data which can be pushed to any external tool that you need to integrate with. For more details, please check - Integrations

Poll Interval (Keeping VWO client up-to-date)

When you initialize the vwoClient on your mobile, it pulls the latest configurations you've done in the VWO application.
If/when you make any changes to the feature flags or rules within VWO after the vwoClient has been initialized on your mobile, there needs to be some way to update your vwoClient with the latest settings from VWO. This can be done via polling.

The poll interval is an optional parameter that allows the SDK to automatically fetch and update settings from the VWO server at specified intervals. Setting this parameter ensures your application always uses the latest configuration.

final vwoInitOptions = VWOInitOptions(
  sdkKey: 'your-sdk-key',
  accountId: 12345,
  pollInterval: 600000  // in milliseconds
);

// Initialize the SDK
final vwoClient = await VWO.init(vwoInitOptions);

Logger

VWO by default logs all ERROR level messages to your mobile console. To gain more control over VWO's logging behavior, you can use the logger parameter in the init configuration.

// Create a custom logger implementation
class DartLogger implements LogTransport {
  @override
  void log(String level, String? message) {
    if (message == null) return;
    print("FME-Flutter: [$level] $message");
  }
}

// Initialize VWO SDK with logger configuration
var transport = <String, dynamic>{};
transport["defaultTransport"] = DartLogger();

var logger = <Map<String, dynamic>>[];
logger.add(transport);

final vwoInitOptions = VWOInitOptions(
  sdkKey: 'your-sdk-key',
  accountId: 12345,
  logger: {"level": "TRACE", "transports": logger},
);

// Initialize the SDK
final vwoClient = await VWO.init(vwoInitOptions);

Please click here for more advanced logger options.

Integrations

VWO FME SDKs provide seamless integration with third-party tools like analytics platforms, monitoring services, customer data platforms (CDPs), and messaging systems. This is achieved through a simple yet powerful callback mechanism that receives VWO-specific properties and can forward them to any third-party tool of your choice.

final vwoInitOptions = VWOInitOptions(
  sdkKey: 'your-sdk-key',
  accountId: 12345,
  integrations: (Map<String, dynamic> properties) {
    print('VWO: Integration callback received: $properties');
  }
);

// Initialize the SDK
final vwoClient = await VWO.init(vwoInitOptions);

Please click here to learn more about Integrations.