# Analytics-Flutter > \[!IMPORTANT] > > The Analytics-Flutter library is currently in public beta and is governed by Segment's [First Access and Beta Preview Terms](https://www.twilio.com/en-us/legal/tos). For more information, see the [Analytics-Flutter GitHub repository](https://github.com/segmentio/analytics_flutter). > \[!WARNING] > > If you've been using Analytics-Flutter since the pilot phase, see [Upgrading from pilot](#upgrading-from-pilot) to use the updated version of Analytics-Flutter. Analytics-Flutter lets you add Segment analytics to your Flutter app. ## Supported platforms Analytics-Flutter supports these platforms: * Android * iOS * MacOS * Web Some destination plugins might not support all platform functionality. Refer to individual platform SDKs for more details. ## Getting started To install Analytics-Flutter: 1. Add the core package as a dependency. ```bash flutter pub add segment_analytics ``` 2. *(Optional)* Add any plugin that you need. ```bash flutter pub add segment_analytics_plugin_firebase ``` 3. Import the library in your Dart code. ```dart import 'package:segment_analytics/client.dart'; ``` 4. Add permissions to `AndroidManifest.xml`. Add the following line between the \`\` tags. ```yml ``` ## Setting up the client The Flutter SDK package exposes a method called `createClient` which you can use to create the Segment Analytics client. This central client manages all of the tracking events. Segment recommends that you add this as a property on your main app's state class. ```text const writeKey = 'SEGMENT_API_KEY'; final analytics = createClient(Configuration(writeKey)); ``` You must pass the `writeKey`. These are the options you can apply to configure the client: | Option Name | Default | Description | | --------------------------------- | --------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `writeKey` *(required)* | '' | Your Segment API key. | | `debug` | false | When this is set to `false`, it won't generate any info logs. | | `collectDeviceId` | false | Set this to `true` to automatically collect the device ID from the DRM API on Android devices. On Apple platforms it will collect the `identifierForVendor` value if available. | | `flushPolicies` | count=30, time=20s | List of flush policies controlling when to send batches of events to the plugins | | `apiHost` | api.segment.io/v1 | Used to specify the regional Segment event endpoint. | | `cdnHost` | cdn-settings.segment.com/v1 | Used to specify the regional Segment settings endpoint. | | `errorHandler` | null | Custom error handler. By default, this logs errors to the standard flutter logger. | | `trackApplicationLifecycleEvents` | false | Set this to `true` to enable automatic tracking for [app lifecycle events](/docs/segment/connections/spec/mobile/#lifecycle-events) which include, application installed, opened, updated, backgrounded. | | `trackDeeplinks` | false | Set this to `true` to enable automatic tracking for when the user opens the app through a deep link. **Note**: When you send this flag, the SDK plugin\_appsflyer ignores [onAppOpenAttribution](https://github.com/AppsFlyerSDK/appsflyer-flutter-plugin/blob/master/doc/Guides.md#Unified-deep-linking). | | `autoAddSegmentDestination` | true | Set this to `false` to skip adding the `SegmentDestination` plugin. | | `defaultIntegrationSettings` | null | Plugin settings that are used if the request to get the settings from Segment fails. | | `maxBatchSize` | true | The maximum number of events you can send to the API at once is 100. | | `appStateStream` | null | Set this to override the stream of application foreground or background events. | | `requestFactory` | true | Set this to override the factory to generate HTTP requests. Type: [RequestFactory](https://github.com/segmentio/analytics_flutter/blob/master/packages/core/lib/state.dart#L546). | ## Upgrading from pilot If you've been using Analytics-Flutter since the pilot phase, follow these steps to use the upgraded version of Analytics-Flutter as Segment renamed the package of the library from `analytics` to `segment_analytics`. 1. Remove the `analytics` package and use `segment_analytics` in your `pubspec.yaml` file. ```diff - analytics: - git: - url: https://github.com/segmentio/analytics_flutter - ref: main - path: packages/core + segment_analytics: ^1.0.1 ``` 2. Change the imports from `package:analytics` to `package:segment_analytics` in your dart files. ```diff - import 'package:analytics/client.dart'; + import 'package:segment_analytics/client.dart'; ``` ## Tracking methods Once you've installed the Analytics-Flutter library, you can start collecting data through Segment's tracking methods: * [Track](#track) * [Screen](#screen) * [Identify](#identify) * [Group](#group) ## Track The [Track](/docs/segment/connections/spec/track/) method is how you record any actions your users perform, along with any properties that describe the action. ## Method signature ```dart Future track(String event: string, {Map? properties}); ``` ## Example use ```dart analytics.track("View Product", properties: { "productId": 123, "productName": "Striped trousers" }); ``` ## Screen The [Screen](/docs/segment/connections/spec/screen/) method lets you record whenever a user sees a screen in your mobile app, along with any properties about the screen. ## Method signature ```dart Future screen(String name: string, {Map? properties}); ``` ## Example use ```dart analytics.screen("ScreenName", properties: { "productSlug": "example-product-123", }); ``` See how to set up [automatic screen tracking](#automatic-screen-tracking). ## Identify The [Identify](/docs/segment/connections/spec/identify/) method lets you tie a user to their actions and record traits about them. This includes a unique user ID and any optional traits you know about them like their email, name, address. The traits option can include any information you might want to tie to the user, but when using any of the [reserved user traits](/docs/segment/connections/spec/identify/#traits), you should make sure to only use them for their intended meaning. All reserved traits are strongly typed by the `UserTraits` class. When you use traits not listed as a reserved user trait, these go under the `custom` property. ## Method signature ```dart Future identify({String? userId, UserTraits? userTraits}); ``` ## Example use ```dart analytics.identify(userId: "testUserId", userTraits: UserTraits( username: "MisterWhiskers", email: "hello@test.com", custom: { "plan": "premium" } ); ``` ## Group The [Group](/docs/segment/connections/spec/group/) method is how you associate an individual user with a group — whether it's a company, organization, account, project, or team. This includes a unique group ID and any optional group traits you know about them like the company name, industry, or the number of employees. The traits option can include any information you might want to tie to the group, but when using any of the [reserved group traits](/docs/segment/connections/spec/group/#traits), you should make sure to only use them for their intended meaning. All reserved traits are strongly typed by the `GroupTraits` class. When you use traits not listed as a reserved user trait, these go under the `custom` property. ## Method signature ```dart Future group(String groupId, {GroupTraits? groupTraits}); ``` ## Example use ```dart analytics.group("some-company", groupTraits: GroupTraits( name: 'Segment', custom: { "region": "UK" } ); ``` ## Utility methods The Analytics-Flutter utility methods help you work with plugins from the analytics timeline. They include: * [Alias](#alias) * [Reset](#reset) * [Flush](#flush) ## Alias The [Alias](/docs/segment/connections/spec/alias/) method is used to merge two user identities, effectively connecting two sets of user data as one. This is an advanced method, but it's required to manage user identities successfully in some of Segment's destinations. ## Method signature ```dart Future alias(String newUserId); ``` ## Example use ```dart analytics.alias("user-123"); ``` ## Reset The Reset method clears the internal state of the library for the current user and group. This is useful for apps where users can log in and out with different identities over time. Note that each time you call Reset, a new AnonymousId generates automatically. ## Method signature ```dart void reset(); ``` ## Example use ```dart analytics.reset(); ``` ## Flush By default, the analytics send to the API after 30 seconds or when 20 items accumulate, whichever happens first, and whenever the app resumes if the user has closed the app with some events unsent. You can modify these values by the `flushAt` and `flushInterval` config options. You can also trigger a flush event manually. ## Method signature ```dart Future flush(); ``` ## Example use ```dart analytics.flush(); ``` ## Advanced cleanup In case you need to reinitialize the client, because you called `createClient` more than once for the same client in your application lifecycle, use this method *on the old client* to clear any subscriptions and timers first. ```dart var analytics = createClient(Configuration(writeKey)); analytics.cleanup(); analytics = createClient(Configuration(writeKey)); ``` If you don't do this, the old client instance still exists and retains the timers, which makes all of your events fire twice. ## Automatic screen tracking Automatic screen tracking enables you to track navigation globally, as sending a Screen event with each navigation action gets tiresome quickly. To set up automatic screen tracking, you need to add the analytics navigator observer to your app's navigator observers. For example, if you're using the `MaterialApp` class, add the following: ```dart return MaterialApp(navigatorObservers: [ ScreenObserver() ]); ``` ## Plugin architecture Segment's plugin architecture enables you to modify and augment how the analytics client works. You have complete control over how the events process before being uploaded to the Segment API. From modifying event payloads to changing analytics functionality, plugins help to speed up the process of getting things done. In order to customize what happens after an event is created, you can create and place various plugins along the processing pipeline that an event goes through. This pipeline is referred to as a timeline. As plugins run through a timeline, they execute in order of insertion based on their entry types. Segment has these five entry types: | Plugin Type | Description | | ------------- | ----------------------------------------------------------------------------------------------- | | `before` | Executes before event processing begins. | | `enrichment` | Executes as the first level of event processing. | | `destination` | Executes as events begin to pass off to destinations. | | `after` | Executes after all event processing completes. This can be used to perform cleanup operations. | | `utility` | Executes only with manual calls such as Logging. | Plugins can have their own native code (for example, the iOS-only `analytics_plugin_idfa`) or wrap an underlying library (such as `analytics_plugin_firebase` which uses `firebase_core` and `firebase_analytics` under the hood). ## Destination plugins Segment is included as a `DestinationPlugin` out of the box. You can add as many destination plugins as you like and upload events and data to them. You can pass `autoAddSegmentDestination = false` in the options when setting up your client to prevent the `SegmentDestination` plugin from being added automatically. ## Adding plugins You can add a plugin at any time through the Add method. ```dart import 'package:segment_analytics/client.dart'; import 'package:segment_analytics/event.dart'; import 'package:segment_analytics/state.dart'; import 'package:segment_analytics_plugin_advertising_id/plugin_advertising_id.dart'; import 'package:segment_analytics_plugin_idfa/plugin_idfa.dart'; import 'package:segment_analytics_plugin_firebase/plugin_firebase.dart' show FirebaseDestination; const writeKey = 'SEGMENT_API_KEY'; class _MyAppState extends State { final analytics = createClient(Configuration(writeKey)); @override void initState() { super.initState(); initPlatformState(); analytics .addPlugin(FirebaseDestination(DefaultFirebaseOptions.currentPlatform)); analytics.addPlugin(PluginAdvertisingId()); analytics.addPlugin(PluginIdfa()); } } ``` ## Writing your own plugins Plugins are implemented by extending one of the provided plugin classes. The available plugin classes are: * `Plugin` * `EventPlugin` * `DestinationPlugin` * `UtilityPlugin` * `PlatformPlugin` Any plugin must be an extension of one of these classes. You can then customize the functionality by overriding different methods on the base class. For example, here is a `Logger` plugin: ```dart import 'dart:convert'; import 'package:segment_analytics/analytics.dart'; import 'package:segment_analytics/event.dart'; import 'package:segment_analytics/plugin.dart'; import 'package:segment_analytics/logger.dart'; class EventLogger extends DestinationPlugin { var logKind = LogFilterKind.debug; EventLogger() : super("event_logger"); @override void configure(Analytics analytics) { pAnalytics = analytics; } @override Future? execute(RawEvent event) async { log("${event.type.toString().toUpperCase()} event${event is TrackEvent ? " (${event.event})" : ''} saved: \n${jsonEncode(event.toJson())}", kind: logKind); return event; } } ``` As it overrides the `execute` method, this `Logger` calls `log` for every event going through the timeline. ## Supported plugins You can use these plugins to meet your tracking needs: | Plugin | Package | | --------------------------------------------------------------------------------------------------------------------------- | --------------------------------- | | [Adjust](https://github.com/segmentio/analytics_flutter/tree/master/packages/plugins/plugin_adjust) | `analytics_plugin_adjust` | | [AppsFlyer](https://github.com/segmentio/analytics_flutter/tree/master/packages/plugins/plugin_appsflyer) | `analytics_plugin_appsflyer` | | [Firebase](https://github.com/segmentio/analytics_flutter/tree/master/packages/plugins/plugin_firebase) | `analytics_plugin_firebase` | | [IDFA](https://github.com/segmentio/analytics_flutter/tree/master/packages/plugins/plugin_idfa) | `analytics_plugin_idfa` | | [Android Advertising ID](https://github.com/segmentio/analytics_flutter/tree/master/packages/plugins/plugin_advertising_id) | `analytics_plugin_advertising-id` | ## Controlling upload with flush policies You can use `FlushPolicies` to more granularly control when events upload. A flush policy defines the strategy for deciding when to flush. This can be on an interval, on a certain time of day, after receiving a certain number of events, or even after receiving a particular event. This gives you more flexibility on when to send events to Segment. To make use of flush policies, you can set them in the configuration of the client: ```dart import 'package:segment_analytics/flush_policies/count_flush_policy.dart'; import 'package:segment_analytics/flush_policies/timer_flush_policy.dart'; final analytics = createClient(Configuration(/*...*/, flushPolicies: [ CountFlushPolicy(10), TimerFlushPolicy(100000) ])); ``` You can set several policies at a time. Whenever any policy decides it's time for a flush, it triggers an upload of the events. The rest are reset so that their logic restarts after every flush. This means only the first policy to reach `shouldFlush` gets to trigger a flush at a time. In the example above, when either the event count gets to 5 or the timer reaches 500ms, whatever comes first triggers a flush. Segment has several standard FlushPolicies: * `CountFlushPolicy` triggers whenever a certain number of events is reached. * `TimerFlushPolicy` triggers on an interval of milliseconds. * `StartupFlushPolicy` triggers on client startup only. ## Adding or removing policies One of the main advantanges of `FlushPolicies` is that you can add and remove policies whenever you want. This is powerful when you want to reduce or increase the amount of flushes. For example, you might want to disable flushes if you detect the user has no network: ```dart if (isConnected) { analytics.addFlushPolicy(policiesIfNetworkIsUp); } else { analytics.removeFlushPolicy(policiesIfNetworkIsUp) } ``` ## Creating your own flush policies You can create a custom `FlushPolicy` for your application needs by implementing the `FlushPolicy` interface. You can also extend the `FlushPolicyBase` class that already creates and handles the `shouldFlush` value reset. A `FlushPolicy` only needs to implement one method: * `onEvent(RawEvent event)`: Gets called on every event tracked by your client. A `FlushPolicy` can optionally implement: * `reset()`: Calls after a flush is triggered either by your policy, by another policy, or manually. * `start()`: Executes when the flush policy is enabled and added to the client. This is a good place to start background operations, make async calls, and configure things before execution. The `FlushPolicy` should have a `shouldFlush` boolean value. When this is set to `true`, the client attempts to upload events. Each policy should reset this value to `false` according to its own logic, although it's pretty common to do it inside the `reset` method. ```dart import 'package:segment_analytics/event.dart'; import 'package:segment_analytics/flush_policies/flush_policy.dart'; class FlushOnScreenEventsPolicy extends FlushPolicy { @override onEvent(RawEvent event) { // Only flush when a screen even happens if (event is ScreenEvent) { this.shouldFlush = true; } } @override reset() { // Superclass will reset the shouldFlush value so that the next screen event triggers a flush again // But you can also reset the value whenever, say another event comes in or after a timeout super.reset(); } } ``` ## Custom logging By default, any logging is done through the standard Flutter logging mechanism. To customize logging, you can build your own logger, which must implement the `LogTarget` mixin. For example: ```dart import 'package:segment_analytics/logger.dart'; void customDebugLog(String msg) { // ... } void customWarningLog(String msg) { // ... } void customErrorLog(String msg) { // ... } class CustomLogger with LogTarget { @override void parseLog(LogMessage log) { switch (log.kind) { case LogFilterKind.debug: customDebugLog("Segment: ${log.message}"); break; case LogFilterKind.warning: customWarningLog("Segment: ${log.message}"); break; case LogFilterKind.error: customErrorLog("Segment: ${log.message}"); break; } } } // Set the default logger to use the CustomLogger LogFactory.logger = CustomLogger(); ``` ## Handling errors You can handle analytics client errors through the `errorHandler` option. The error handler configuration receives a function which gets called whenever an error happens on the analytics client. It receives an Exception that extends one of the errors from [errors.dart](https://github.com/segmentio/analytics_flutter/blob/main/packages/core/lib/errors.dart). You can use this error handling to trigger different behaviors in the client when a problem occurs. For example, if the client gets rate limited, you could use the error handler to swap flush policies to be less aggressive. ```dart import 'package:segment_analytics/errors.dart'; //... final flushPolicies = [CountFlushPolicy(5), TimerFlushPolicy(500)]; void errorHandler(Exception error) { if (error is NetworkServerLimited) { // Remove all flush policies analytics.removeFlushPolicy(analytics.getFlushPolicies()); // Add less persistent flush policies analytics.addFlushPolicy([ CountFlushPolicy(100), TimerFlushPolicy(5000) ]); } } final analytics = createClient(Configuration(writeKey), errorHandler: errorHandler, flushPolicies: flushPolicies); ``` ## Reporting errors from plugins Plugins can also report errors to the handler by using the [`.error`](https://github.com/segmentio/analytics_flutter/blob/main/packages/core/lib/analytics.dart#L52) function of the analytics client. Segment recommends you to use the `PluginError` for consistency, and to attach the `innerError` with the actual exception that was hit. ```dart import 'package:segment_analytics/errors.dart'; //... try { distinctId = await mixpanel.getDistinctId(); } catch (e) { analytics.error( PluginError('Error: Mixpanel error calling getDistinctId', e) ); } ``` ## Platfom specific info ## Web `analytics_flutter` on web checks for `Analytics.JS` userInfo cookies/localStorage and reuses the `anonymousId` data. LocalStorage recovery only works when running in the same domain/subdomain. ## Example app See the [example app](https://github.com/segmentio/analytics_flutter/blob/main/example/README.md) to check a full test app of how to integrate Analytics-Flutter into your own Flutter app.