Flutter SDK

This is the official documentation for the Amplitude Analytics Flutter SDK.

Installation¶

Add dependencies¶

1. Go to the pubspec.yaml file and add Amplitude SDK as a dependency.

   dependencies:
     amplitude_flutter: ^3.13.0
   

2. Run flutter pub get in the terminal to install the SDK.

iOS installation¶

Add platform :ios, '10.0' to your Podfile.

To enable Bitcode, follow Flutter's documentation.

Usage and examples¶

Initialization¶

Before you can instrument, you must initialize the SDK using the API key for your Amplitude project.

import 'package:amplitude_flutter/amplitude.dart';
import 'package:amplitude_flutter/identify.dart';

class YourClass {
  Future<void> exampleForAmplitude() async {
    // Create the instance
    final Amplitude analytics = Amplitude.getInstance(instanceName: "project");

    // Initialize SDK
    analytics.init(widget.apiKey);

    // Log an event
    analytics.logEvent('MyApp startup', eventProperties: {
      'friend_num': 10,
      'is_heavy_user': true
    });
  }
}

Configuration¶

Amplitude Flutter SDK runs on the top of the Amplitude Android Maintenance SDK, Amplitude iOS Maintenance SDK and Amplitude JavaScript Maintenance SDK. The following are the Dart settable config options. For other default configurations:

• on Android side, check the Android Configuration
• on iOS side, check the iOS configuration
• on browser side, please check the browser configuration

Configure batching behavior¶

To support high-performance environments, the SDK sends events in batches. Every event logged by the logEvent method is queued in memory. Events are flushed in batches in background. You can customize batch behavior with setEventUploadThreshold. By default, the serverUrl will be https://api2.amplitude.com/. This SDK doesn't support batch mode, the batch API endpoint.

// Events queued in memory will flush when number of events exceed upload threshold
// Default value is 30
Amplitude.getInstance().setEventUploadThreshold(1);

// Events queue will flush every certain milliseconds based on setting
// Default value is 30,000 milliseconds
Amplitude.getInstance().setEventUploadPeriodMillis(10000);

EU data residency¶

Beginning with version 3.6.0, you can configure the server zone after initializing the client for sending data to Amplitude's EU servers. The SDK sends data based on the server zone if it's set. The server zone configuration supports dynamic configuration as well.

For earlier versions, you need to configure the serverURL property after initializing the client.

// For versions starting from 3.6.0
// No need to call setServerUrl for sending data to Amplitude's EU servers
Amplitude.getInstance().setServerZone("EU");

// For earlier versions
Amplitude.getInstance().setServerUrl("https://api.eu.amplitude.com")

Send events¶

Basic events¶

Events represent how users interact with your application. For example, "button clicked" may be an action you want to track.

Amplitude.getInstance().logEvent('BUTTON_CLICKED');

Events with properties¶

Events can also contain properties. They provide context about the event taken. For example, "hover time" may be a relevant event property to "button click"

Amplitude.getInstance().logEvent('BUTTON_CLICKED', {"Hover Time": "100ms"});

Flush events¶

Events are typically stored in a buffer and flushed periodically. This behavior is configurable. You can also flush events manually

Amplitude.getInstance().uploadEvents();

User properties¶

User properties help you understand your users at the time they performed some action within your app such as their device details, their preferences, or language. Amplitude-Flutter's identify manages this feature. You need to import identify before using it.

import 'package:amplitude_flutter/identify.dart';

Set a user property¶

set¶

set sets the value of a user property. You can also chain together multiple identify calls.

final Identify identify = Identify()
                          ..set('gender','female')
                          ..set('age',20);
Amplitude.getInstance().identify(identify);

setOnce¶

setOnce sets the value of a user property one time. Later calls using setOnce are ignored.

final Identify identify1 = Identify();
identify1.setOnce('sign_up_date', '2015-08-24');
Amplitude.getInstance().identify(identify1);
final Identify identify2 = Identify();
identify2.setOnce('sign_up_date', '2015-08-24');
Amplitude.getInstance().identify(identify2);// is ignored

add¶

add increments a user property by some numerical value. If the user property doesn't have a value set yet, it's initialized to 0 before being incremented.

final Identify identify = Identify().add('karma', 0.123);
Amplitude.getInstance().identify(identify);

preInsert¶

Adds a value or values to a user property at the beginning of the list, if the value doesn't exist in the user property yet. If the user property doesn't have a value set yet, it's initialized to an empty list before the new values are pre-inserted. If the user property has an existing value, nothing happens.

final Identify identify = Identify()
                          ..preInsert('existing_list', 'some_property')
Amplitude.getInstance().identify(identify);

postInsert¶

Adds a value or values to a user property at the end of the list, if the value doesn't exist in the user property yet. If the user property doesn't have a value set yet, it's initialized to an empty list before the new values are inserted. If the user property has an existing value, nothing happens.

final Identify identify = Identify()
                          ..postInsert('existing_list','some_property')
Amplitude.getInstance().identify(identify);

Set multiple user properties¶

You can use setUserProperties as a shorthand to set multiple user properties at one time. This method is a wrapper around Identify.set and identify.

Map<String, dynamic> userProps = {
  'KEY': 'VALUE',
  'OTHER_KEY': 'OTHER_VALUE'
};
Amplitude.getInstance().setUserProperties(userProperties);

Arrays in user properties¶

You can use arrays as user properties. You can directly set arrays or use append to generate an array.

const colors = ["rose", "gold"];
const numbers = [4, 5];
final Identify identify = Identify()
                          ..set("colors", colors)
                          ..append("ab-tests", "campaign_a")
                          ..prepend("existing_list", numbers);
Amplitude.getInstance().identify(identify);

prepend and append¶

• prepend prepends a value or values to a user property.
• append appends a value or values to a user property array. If the user property doesn't have a value set yet, it's initialized to an empty list before the new values are added. If the user property has an existing value and it's not a list, it's converted into a list with the new value added.

const array = ["some_string", 56];
final Identify identify = Identify()
                          ..append("ab-tests", "new-user-test")
                          ..prepend("some_list", array)
Amplitude.getInstance().identify(identify);

Remove user properties¶

Clear all user properties¶

clearUserProperties clears all the current user's user properties.

Amplitude.getInstance().clearUserProperties();

remove¶

remove removes a value or values from a user property. If the item doesn't exist in the user property, nothing happens.

const array = ["some_string", 56];
final Identify identify = Identify()
                          ..remove("ab-tests", "new-user-test")
                          ..remove("some_list",array);
Amplitude.getInstance().identify(identify);

unset¶

unset unsets and removes a user property.

final Identify identify = Identify()
                          ..unset("ab-tests", "new-user-test")
                          ..unset("some_list",array);
Amplitude.getInstance().identify(identify)

User groups¶

Amplitude supports assigning users to groups and performing queries, such as Count by Distinct, on those groups. If at least one member of the group has performed the specific event, then the count includes the group.

For example, you want to group your users based on what organization they're in by using an 'orgId'. Joe is in 'orgId' '10', and Sue is in 'orgId' '15'. Sue and Joe both perform a certain event. You can query their organizations in the Event Segmentation Chart.

When setting groups, define a groupType and groupName. In the previous example, 'orgId' is the groupType and '10' and '15' are the values for groupName. Another example of a groupType could be 'sport' with groupName values like 'tennis' and 'baseball'.

Setting a group also sets the groupType:groupName as a user property, and overwrites any existing groupName value set for that user's groupType, and the corresponding user property value. groupType is a string, and groupName can be either a string or an array of strings to indicate that a user is in multiple groups.

// set group with a single group name
Amplitude.getInstance().setGroup("orgId", "15");

// set group with multiple group names
Amplitude.getInstance().setGroup("sport", ["tennis", "soccer"]);

Track revenue¶

Amplitude can track revenue generated by a user. Revenue is tracked through distinct revenue objects, which have special fields that are used in Amplitude's Event Segmentation and Revenue LTV charts. This allows Amplitude to automatically display data relevant to revenue in the platform.

String productId = "product001";
int quantity = 2;
double price = 20;
double amount = 35;
Amplitude.getInstance().logRevenue(productId, quantity, price);
Amplitude.getInstance().logRevenueAmount(amount);

Group user properties¶

Use the Group Identify API to set or update the properties of particular groups. Keep these considerations in mind:

• Updates affect only future events, and don't update historical events.
• You can track up to 5 unique group types and 10 total groups.

The groupIdentify method accepts a group type string parameter and group name object parameter, and an Identify object that's applied to the group.

final Identify identify = Identify()
                          ..set("gender", "female")
                          ..set("age", 20);
Amplitude.getInstance().groupIdentify("groupType", "groupValue", identify);

User sessions¶

A session is a period of time that a user has the app in the foreground. Events that are logged within the same session have the same session_id. Sessions are handled automatically so you don't have to manually call an API like startSession() or endSession(). Amplitude groups events together by session. A session represents a single period of user activity, with a start and end time. Different SDKs track sessions differently, depending on the requirements of the platform. On Android and iOS, you can choose to automatically log start and end session events corresponding to the start and end of a user's session. This is not supported on Flutter Web.

//Enable automatically log start and end session events
Amplitude.getInstance().trackingSessionEvents(true);
//Disable automatically log start and end session events
Amplitude.getInstance().trackingSessionEvents(false);

trackingSessionEvents() is not supported on Flutter web. Please check here to learn more.

Set custom user ID¶

If your app has its login system that you want to track users with, you can call setUserId at any time.

Amplitude.getInstance().setUserId("test_user_id");

Set custom device ID¶

By default, device IDs are randomly generated UUIDs. You can define a custom device ID by calling setDeviceId.

Amplitude.getInstance().setDeviceId('test_device_id');

You can retrieve the device ID that Amplitude uses with Amplitude.getInstance().getDeviceId(). This method can return null if a deviceId hasn't been generated yet.

Advanced topics¶

COPPA Control¶

COPPA (Children's Online Privacy Protection Act) restrictions on IDFA, IDFV, city, IP address and location tracking can be enabled or disabled all at once. Remember that apps asking for information from children under 13 years of age must comply with COPPA.

// Enable COPPA Control
Amplitude.getInstance().enableCoppaControl();
// Disable COPPA Control
Amplitude.getInstance().disableCoppaControl();

Advertising ID¶

Advertiser ID (also referred to as IDFA) is a unique identifier provided by the iOS and Google Play stores. As it's unique to every person and not just their devices, it's useful for mobile attribution.  Mobile attribution is the attribution of an installation of a mobile app to its original source (for example, and ad campaign or app store search).

Mobile apps need permission to ask for IDFA, and apps targeted to children can't track at all. Consider IDFV, device id, or an email login system as alternatives when IDFA isn't available.

See iOS Advertising ID or the Android Advertising ID for more information.

Opt out of tracking¶

Users may wish to opt out of tracking entirely, which means no events and no records of their browsing history are tracked. setOptOut provides a way to fulfill user requests for privacy.

//Disables instrumentation
Amplitude.getInstance().setOptOut(true);
//Enables instrumentation
Amplitude.getInstance().setOptOut(false);

Dynamic configuration¶

Flutter SDK lets users configure their apps to use dynamic configuration. This feature finds the best server URL automatically based on app users' location.

• If you have your own proxy server and use setServerUrl API, don't use dynamic configuration.
• If you have users in Mainland China, Amplitude recommends that you use dynamic configuration.
• By default, this feature is off. You must explicitly enable it to use it.
• By default, this feature returns server URLs for Amplitude's US servers. If you need to send data to Amplitude's EU servers, use setServerZone to set it to EU zone.

Amplitude.getInstance().setUseDynamicConfig(true);

Flutter web support¶

Flutter web support delivers the same experiences on the web as on mobile. Amplitude-Flutter starts to support flutter web from v3.8.0.

These features aren't supported in Flutter web:

• enableCoppaControl
• disableCoppaControl
• trackingSessionEvents. While Flutter Web doesn’t support the ability to send Start Session and End Session events automatically, the SDK will automatically track session IDs. You can use this for common session-based analyses like the User Session and Pathfinder charts. See our help docs on tracking sessions in Amplitude to learn more.
• useAppSetIdForDeviceId

Usage¶

Append the following Amplitude-JavaScript snippet into web/index.html in your Flutter project. The Amplitude-JavaScript version must be v8.12.0 and higher.

<script type="text/javascript" defer>
   (function(e,t){var n=e.amplitude||{_q:[],_iq:{}};var r=t.createElement("script")
    ;r.type="text/javascript"
    ;r.integrity="sha384-UcvEbHmT0LE2ZB30Y3FmY3Nfw6puAKXz/LpCFuoywywYikMOr/519Uu1yNq2nL9w"
    ;r.crossOrigin="anonymous";r.async=true
    ;r.src="https://cdn.amplitude.com/libs/amplitude-8.12.0-min.gz.js"
    ;r.onload=function(){if(!e.amplitude.runQueuedFunctions){
    console.log("[Amplitude] Error: could not load SDK")}}
    ;var s=t.getElementsByTagName("script")[0];s.parentNode.insertBefore(r,s)
    ;function i(e,t){e.prototype[t]=function(){
    this._q.push([t].concat(Array.prototype.slice.call(arguments,0)));return this}}
    var o=function(){this._q=[];return this}
    ;var a=["add","append","clearAll","prepend","set","setOnce","unset","preInsert","postInsert","remove"]
    ;for(var c=0;c<a.length;c++){i(o,a[c])}n.Identify=o;var u=function(){this._q=[]
    ;return this}
    ;var l=["setProductId","setQuantity","setPrice","setRevenueType","setEventProperties"]
    ;for(var p=0;p<l.length;p++){i(u,l[p])}n.Revenue=u
    ;var d=["init","logEvent","logRevenue","setUserId","setUserProperties","setOptOut","setVersionName","setDomain","setDeviceId","enableTracking","setGlobalUserProperties","identify","clearUserProperties","setGroup","logRevenueV2","regenerateDeviceId","groupIdentify","onInit","logEventWithTimestamp","logEventWithGroups","setSessionId","resetSessionId","getDeviceId","getUserId","setMinTimeBetweenSessionsMillis","setEventUploadThreshold","setUseDynamicConfig","setServerZone","setServerUrl","sendEvents","setLibrary","setTransport"]
    ;function v(e){function t(t){e[t]=function(){
    e._q.push([t].concat(Array.prototype.slice.call(arguments,0)))}}
    for(var n=0;n<d.length;n++){t(d[n])}}v(n);n.getInstance=function(e){
    e=(!e||e.length===0?"$default_instance":e).toLowerCase()
    ;if(!Object.prototype.hasOwnProperty.call(n._iq,e)){n._iq[e]={_q:[]};v(n._iq[e])
    }return n._iq[e]};e.amplitude=n})(window,document);
</script>

Compatibility Matrix¶

The following matrix lists the minimum support for Amplitude Flutter SDK version. For Gradle Version lower than v6.7.1, use Amplitude Flutter v3.10.0.

Learn more about the Android Gradle Plugin compatibility, Gradle compatibility, and Kotlin compatibility.

Troubleshooting¶

If you have issues turning on Bitcode in iOS follow Flutter's documentation

More resources¶

If you have any problems with the SDK, create a GitHub issue or submit a request on Amplitude Help.