Collecting data with Trackers and Webhooks

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  7. Android Tracker v1.x
  8. Android (1.2.0)

Android (1.2.0)


1.2.0 has a critical bug which causes duplication of natively supported and enabled contexts. 1.2.1 is released to patch this bug. Thanks for the understanding.


In order to add the tracker to your project, you must add it as a dependency.


If you use Gradle, here’s how to add the tracker to your project.

Start by adding jcenter() to your build.gradle file:

repositories { ... jcenter() }

Then add into the same file:

dependencies { ... // Snowplow Android Tracker compile 'com.snowplowanalytics:snowplow-android-tracker:1.2.0@aar' }
Code language: JavaScript (javascript)

This will install version 1.2.0 of the Android tracker. If you would like to ensure that all bug fixes and patches for version 1.2.0 are installed, simply change 1.2.0 into 1.2.+.

dependencies { ... // Snowplow Android Tracker compile 'com.snowplowanalytics:snowplow-android-tracker:1.2.+@aar' }
Code language: JavaScript (javascript)

Note: no breaking changes will occur in the ‘1.2.x’ space.

A complete Gradle file may look like this:

repositories { maven { url "" } } dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) implementation 'android.arch.lifecycle:extensions:$project.archLifecycleVersion' implementation '' implementation '' // Optional Google Analytics Library // - Required to get the IDFA Code implementation '' // Required Dependency for the Tracker implementation 'com.squareup.okhttp3:okhttp:3.4.1' // Tracker Import implementation 'com.snowplowanalytics:snowplow-android-tracker:1.2.0@aar' }
Code language: PHP (php)

Demo apps

With the tracker we’ve included a demo app that shows an example of how to integrate the tracker.

For general testing, Snowplow Mini can be used as an easily deployable collector with a live web interface for viewing received events.

The app can be run in the Android Studio emulator or on an actual device.

Simply enter the endpoint of the collector in the app’s interface once it’s launched and press "send events"!

Quick Start

Add the following snippet to a file (e.g.

import com.snowplowanalytics.snowplow.tracker.*; import android.content.Context; public class SnowplowTrackerBuilder { public static Tracker getTracker(Context context) { Emitter emitter = getEmitter(context); Subject subject = getSubject(context); // Optional return Tracker.init(new Tracker.TrackerBuilder(emitter, "your-namespace", "your-appid", context) .subject(subject) // Optional .build() ) } private static Emitter getEmitter(Context context) { return new Emitter.EmitterBuilder("", context) .build(); } private static Subject getSubject(Context context) { return new Subject.SubjectBuilder() .context(context) .build(); } }
Code language: PHP (php)


To send the events, you need to update your AndroidManifest.xml with the following permission:

<uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
Code language: HTML, XML (xml)

If you want to send location information with each event you will need to add the following permissions to your AndroidManifest.xml:

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
Code language: HTML, XML (xml)

Send events

Now you can try to track events:

Tracker tracker = SnowplowTrackerBuilder.getTracker(activity, context); tracker.track(ScreenView.builder().name("screenName").id("screenId").build());
Code language: JavaScript (javascript)

Tracker structure

Here we’ll explain the purpose of the classes provided in the tracker.


Responsible for all the storage, networking and scheduling required to ensure events are sent to a collector.

Details like the collector endpoint and sending timeout lengths are set here.


Tracker is the class where you can find the methods available for tracking events. This is also where all parts of the tracker are brought together, i.e. within Tracker you must set the associated emitter, subject, etc.


Payload is simply a key-value store used for constructing events.


SelfDescribingJson is the class used for making self-describing JSONs (SDJs).

An SDJ has a schema field that holds a URI (string) that identifies the structure of the data nested in the data field.

All events sent to the collector are self-describing JSONs.

When sending your own custom events, you will want to create a SelfDescribingJson object given two arguments: the schema, and a Map<String, String> or Map<String, Object> that holds the data you’d like to track.


A “subject” represents an individual user that is being tracked. It is used to track data that persists with a user like timezone, user ID, platform, etc.


This is where all events are found, the available classes are:

  • PageView
  • Structured
  • Unstructured
  • ScreenView
  • ConsentWithdrawn
  • ConsentGranted
  • ConsentDocument
  • Timing
  • EcommTransaction
  • EcommTransactionItem
  • NotificationContent
  • PushNotification

Events are sent by providing them as arguments to the tracking methods found in Tracker.

Screenview events

A screenview event can be manually tracked like this:

tracker.track(ScreenView.builder() .name("Product list") .id("UUID string") .type("ListView") .previousName("User grid") .previousId("another Id") .previousType("GridView") .transitionType("swipe") .build());
Code language: CSS (css)


This is a class that defines callbacks that are called when an emitter either fails or succeeds to send requests.

Tracking basic methods

Creating an emitter

Every tracker must have an emitter in order to send events.

Note: the URL endpoint is the only required parameter.

Here’s an example that creates an emitter:

Emitter e2 = new Emitter .EmitterBuilder("com.collector.acme", Context context) // Required .method(HttpMethod.GET) // Optional - Defines how we send the request .option(BufferOption.Single) // Optional - Defines how many events we bundle in a POST .security(RequestSecurity.HTTPS) // Optional - Defines what protocol used to send events .tls(TLSVersion.TLSv1_2) // Optional - Defines what TLS versions are used for the request .callback(new EmitterCallback() {...}) .build();
Code language: JavaScript (javascript)

Creating a tracker

To instantiate a tracker in your code simply instantiate the Tracker class with the following builder pattern:

// Create a Tracker with all options Tracker.init(new Tracker .TrackerBuilder(e2, "myNamespace", "myAppId", getContext()) .base64(false) // Optional - defines if we use base64 encoding .platform(DevicePlatforms.Mobile) // Optional - defines what platform the event will report to be on .subject(new Subject.SubjectBuilder().build()) // Optional - a subject which contains values appended to every event .build() );
Code language: JavaScript (javascript)

Sending events

The following methods are available for sending events from the tracker:

Attaching contexts to events

Contexts augment events with additional information. The tracker has standard contexts for automatically attaching useful information like geolocation, session, or app version/build to every event.

Each event has an argument for custom contexts in order to attach information that isn’t covered by standard contexts.

The custom context argument should consist of a List of SelfDescribingJson representing an array of one or more contexts. The format of each individual context element is the same as for an unstructured event (referring to the fact that it consists of a schema and data field – they’re all self-describing JSONs).

If a visitor arrives on a page advertising a movie, the context dictionary might look like this:

{ "schema": "iglu:com.acme_company/movie_poster/jsonschema/2-1-1", "data": { "movieName": "The Guns of Navarone", "posterCountry": "US", "posterYear": "1961" } }
Code language: JSON / JSON with Comments (json)

The corresponding Map can be used to create a SelfDescribingJson:

// Create a Map of the data you want to include... Map<String, String> dataMap = new HashMap<>(); dataMap.put("movie_name", "solaris"); dataMap.put("poster_country", "JP"); dataMap.put("poster_year", "1978"); // Now create your SelfDescribingJson object... SelfDescribingJson context1 = new SelfDescribingJson("iglu:com.acme/movie_poster/jsonschema/2-1-1", dataMap);
Code language: JavaScript (javascript)

Sending the movie poster context with an event looks like this:

// Now add this JSON into a list of SelfDescribingJsons... List<SelfDescribingJson> contexts = new ArrayList<>(); contexts.add(context1);
Code language: PHP (php)

Note: even if there is only one custom context attached to the event, it still needs to be placed in an array.

More advanced methods

Tracking features

Event types

ScreenView tracking

Auto-tracking can be enabled to send screen view events whenever a screen is changed in the app.

Tracker.init(new Tracker.TrackerBuilder(...) .screenviewEvents(true) .build() );
Code language: CSS (css)
PageView event

Use PageView events to track a user viewing a web page within your app:

tracker.track(PageView.builder() .pageUrl("") .pageTitle("example") .referrer("") .build());
Code language: CSS (css)
EcommerceTransaction event

Use an e-commerce transaction event to track things like online purchases. Transaction items are attached to an e-commerce event in order to record individual items in a transaction.

Note: that tracking an e-commerce transaction sends multiple events: one transaction event for the transaction as a whole, and one transaction item event for each element of the items list. Each transaction item event will have the same timestamp, order_id, and currency as the main transaction event.

Here is an example:

// Create some Transaction Items EcommerceTransactionItem item1 = EcommerceTransactionItem.builder() .itemId("item_id_1") .sku("item_sku_1") .price(1.00) .quantity(1) .name("item_name") .category("item_category") .currency("currency") .build(); EcommerceTransactionItem item2 = EcommerceTransactionItem.builder() .itemId("item_id_2") .sku("item_sku_2") .price(1.00) .quantity(1) .name("item_name") .category("item_category") .currency("currency") .build(); // Add these items to a List List<EcommerceTransactionItem> items = new ArrayList<>(); items.add(item1); items.add(item2); // Now track the transaction by using this list of items as an argument tracker.track(EcommerceTransaction.builder() .orderId("6a8078be") .totalValue(300.00) .affiliation("my_affiliate") .taxValue(30.00) .shipping(10.00) .city("Boston") .state("Massachusetts") .country("USA") .currency("USD") .items(items) .build()); // Or include the items as varargs in the items section tracker.track(EcommerceTransaction.builder() .orderId("6a8078be") .totalValue(300.00) .affiliation("my_affiliate") .taxValue(30.00) .shipping(10.00) .city("Boston") .state("Massachusetts") .country("USA") .currency("USD") .items(item1, item2) .build());
Code language: PHP (php)
Structured event

Use structured events to track a custom event happening in your app which fits the Google Analytics-style structure of having up to five fields (with only the first two required):

tracker.track(Structured.builder() .category("shop") .action("add-to-basket") .label("Add To Basket") .property("pcs") .value(2.00) .build());
Code language: CSS (css)
Self-describing event

A SelfDescribingJson is used as a wrapper around either a TrackerPayload, another SelfDescribingJson or a Map object. After creating the object you want to wrap, you can create a SelfDescribingJson and track it like this:

// This is the Map we have created Map<String, String> eventData = new HashMap<>(); eventData.put("Event", "Data") // We wrap that map in a SelfDescribingJson before sending it SelfDescribingJson json = new SelfDescribingJson("iglu:com.acme/example/jsonschema/1-0-0", eventData); // Now track the event tracker.track(json);
Code language: JavaScript (javascript)
Timing event

Use a timing event to track a custom timing:

tracker.track(Timing.builder() .category("category") .variable("variable") .timing(1) .label("label") .build());
Code language: CSS (css)
ConsentGranted event

Consent-granted events are used to track when a user consents to data collection:

t1.track(ConsentGranted.builder() .expiry("Monday, 19-Aug-05 15:52:01 UTC") .documentVersion("5") .documentId("1234") .build());
Code language: CSS (css)
ConsentWithdrawn event

Consent-withdrawn events are used to track when a user withdraws consent to data collection:

t1.track(ConsentWithdrawn.builder() .all(true) .build()); t1.track(ConsentWithdrawn.builder() .all(false) .documentVersion("5") .documentId("1234") .documentDescription("An example description") .documentName("Consent document") .customContext(contextList) .timestamp(1423583655000) .eventId("uid-1") .build());
Code language: CSS (css)
Consent documents

Consent documents (documents that detail an agreement around data privacy) can be attached to consent events where they’re applicable.

When a consent event is sent for collection, the consent documents will be added as contexts.

For example:

// Create some consent documents ConsentDocument document1 = ConsentDocument.builder() .documentId("doc-id1") .documentVersion("1") .build(); ConsentDocument document2 = ConsentDocument.builder() .documentId("doc-id2") .documentVersion("1") .documentName("document name") .documentDescription("document description") .build(); // Add these items to a List List<ConsentDocument> documents = new ArrayList<>(); documents.add(document1); documents.add(document2); // Now Track the Transaction by using this list of items as an argument t1.track(ConsentGranted.builder() .expiry("Monday, 19-Aug-05 15:52:01 UTC") .documentVersion("5") .documentId("1234") .documentDescription("An example description") .documentName("Consent document") .consentDocuments(documents) .customContext(contextList) .timestamp(1423583655000) .eventId("uid-1") .build());
Code language: PHP (php)

Session tracking

By default, no client session tracking is activated. Once enabled the tracker will start appending a client_session context to each event it sends and it will maintain this session information for the life of the application, i.e. as long as the application is installed on the device.

Sessions correspond to tracked user activity. A session expires when no tracking events have occurred for the amount of time defined in a timeout. When a session expires, the session ID is incremented and session checking will stop. There are two timeouts since a session can timeout in the foreground (while the app is visible) or in the background (when the app has been suspended, but not closed).

Tracker.init(new Tracker.TrackerBuilder( ... ) .sessionContext(true) // To use the session context .sessionCheckInterval(10) // Checks every 10 seconds (default is 15) .foregroundTimeout(300) // Timeout after 5 minutes (default is 10) .backgroundTimeout(120) // Timeout after 2 minutes (default is 5) .build() );
Code language: JavaScript (javascript)
Foreground and background events

Events can be sent whenever the app is foregrounded and backgrounded.

In order to enable these events, use the builder method lifecycleEvents during initialization of the tracker:

Tracker.init(new Tracker.TrackerBuilder(emitter, namespace, appId, this.getApplicationContext()) .lifecycleEvents(true) .build() );
Code language: CSS (css)

Foreground events are sent whenever an app is opened or resumed.

Background events are sent whenever an app is moved to the background.

Events are not sent on app close since the OS cannot guarantee advance notice of app closing.

Install tracking

Auto-tracking can be enabled to send an install event whenever the tracker is used for the first time in an app. The tracker will record when it’s first been installed, so deleting and reinstalling an app will trigger another install event.

If install auto-tracking is not enabled, the tracker will still keep track of when the app was first installed, so that when enabled, the tracker will send the recorded install event with a timestamp reflecting when it was first installed.

Tracker.init(new Tracker.TrackerBuilder(...) .installTracking(true) .build() );
Code language: CSS (css)
Crash tracking

Auto-tracking for application crashes can be enabled to send events that capture exception information.

Tracker.init(new Tracker.TrackerBuilder(...) .applicationCrash(true) .build() );
Code language: CSS (css)

Standard contexts

These are out-of-the-box tracker options that when enabled will attach useful contexts to every event.

Session context

The session context includes sessionization information like user ID and session ID that can be used to relate user activity patterns to events.

Tracker.init(new Tracker.TrackerBuilder( ... ) .sessionContext(true) // To use the session context .sessionCheckInterval(10) // Checks every 10 seconds (default is 15) .foregroundTimeout(300) // Timeout after 5 minutes (default is 10) .backgroundTimeout(120) // Timeout after 2 minutes (default is 5) .build() );
Code language: JavaScript (javascript)
Mobile context

The mobile context contains information like OS version, device model, carrier and more.

It is enabled when creating the tracker:

Tracker.init(new Tracker.TrackerBuilder(...) .mobileContext(true) .build() );
Code language: CSS (css)
Geolocation context

The geolocation context contains information like the coordinates, speed and bearing of the device.

It is enabled when creating the tracker:

Tracker.init(new Tracker.TrackerBuilder(...) .geoLocationContext(true) .build() );
Code language: CSS (css)

Note: permissions are required in your application for accessing geolocation information. Make sure to include GPS permissions in AndroidManifest.xml and request location access from the user.

Application context

The application context includes app build and version number.

Tracker.init(new Tracker.TrackerBuilder(...) .applicationContext(true) .build() );
Code language: CSS (css)
Screen Context

The screen context contains information related to the current screen being viewed on the device when the event is created.

Tracker.init(new Tracker.TrackerBuilder(...) .screenContext(true) .build() );
Code language: CSS (css)

Emitter options

These options are used to fine-tune the emitter.

Setting the request method

The request method used to connect to the collector, either: HttpMethod.GET, or HttpMethod.POST.

Emitter e2 = new Emitter .EmitterBuilder("com.collector.acme", Context context) // Required .method(HttpMethod.GET) // Optional - Defines how we send the request .build();
Code language: JavaScript (javascript)

In a GET request, each event is sent in an individual request. In a POST request, events can be bundled together in one request.

Setting the emit timeout

The maximum timeout for emitting events

Emitter e2 = new Emitter .EmitterBuilder("com.collector.acme", Context context) // Required .emitTimeout(5) .build();
Code language: JavaScript (javascript)

Configure the buffer

A buffer is used to group events together in bulk before sending them. This is especially handy to reduce network usage. By default, the Emitter buffers up to 10 events together before sending them; only available if you are using POST as your request type.

The buffer can be configured when creating the emitter:

Emitter e2 = new Emitter .EmitterBuilder("com.collector.acme", Context context) // Required .option(BufferOption.Single) // Optional - Defines how many events we bundle in a POST .build();
Code language: JavaScript (javascript)
SingleEvents are sent individually
DefaultGroupSends events in groups of 10 events or less
HeavyGroupSends events in groups of 25 events or less

Note: Buffer options will only ever influence how POST request are sent however. All GET requests will be sent individually.

Setting the protocol

The protocol used to connect to the collector, either: RequestSecurity.HTTP, or RequestSecurity.HTTPS.

Emitter e2 = new Emitter .EmitterBuilder("com.collector.acme", Context context) // Required .security(RequestSecurity.HTTPS) // Optional - Defines what protocol used to send events .build();
Code language: JavaScript (javascript)

Setting the TLS version

TLS is a cryptography protocol needed if you’ve chosen to send events over HTTPS.

To specify a specific version, supply TLSVersion (or for multiple versions, EnumSet<TLSVersion>) to the tls builder method:

Emitter e2 = new Emitter .EmitterBuilder("com.collector.acme", Context context) // Required .tls(TLSVersion.TLSv1_2) // Optional - Defines what TLS versions are used for the request .build();
Code language: JavaScript (javascript)

Setting a callback

An emitter callback can be set which will be called with the count of successful and failed events.

First create the callback you’d like to define, and then supply it to an emitter:

RequestCallback callback = new RequestCallback() { @Override public void onSuccess(int successCount) { Log.d("Tracker", "Buffer length for POST/GET:" + successCount); } @Override public void onFailure(int successCount, int failureCount) { Log.d("Tracker", "Failures: " + failureCount + "; Successes: " + successCount); } }); Emitter emitter = new Emitter .EmitterBuilder("com.collector.acme", Context context) .callback(callback) .build();
Code language: JavaScript (javascript)

Send limit

The number of events retrieved from storage in the database whenever the emitter needs more to send.

Emitter e2 = new Emitter .EmitterBuilder("com.collector.acme", Context context) // Required .sendLimit(250) .build();
Code language: JavaScript (javascript)

GET byte limit

The maximum data size of GET requests made by the emitter to send events.

Emitter e2 = new Emitter .EmitterBuilder("com.collector.acme", Context context) // Required .byteLimitGet(40000) .build();
Code language: JavaScript (javascript)

POST byte limit

The maximum data size of POST requests made by the emitter to send events.

Emitter e2 = new Emitter .EmitterBuilder("com.collector.acme", Context context) // Required .byteLimitGet(40000) .build();
Code language: JavaScript (javascript)

Global Contexts

Apart from the predefined contexts that are sent with every event, custom contexts are added to events individually. However there are times when we wish to attach a custom context to every event, or a set of events automatically. Global contexts are introduced to meet this requirement: send custom contexts with every event or a set of events based on criterias specified by the user.

Context primitives

Context primitive is a term for anything that can be used as a context. A context primitive is either a self-describing JSON, or a callback that creates a self-describing JSON.

Self-describing JSON

Custom contexts are represented as self describing JSONs and they can be used as a global context when you’d like define a context that is attached to every event and its’ content never changes.

Map<String, String> attributes = new HashMap<>(); attributes.put("test-key-1", "test-value-1"); GlobalContext testCtx = new SelfDescribingJson("sdjExample", "iglu:com.snowplowanalytics.snowplow/test_sdj/jsonschema/1-0-1", attributes); Tracker.instance().addGlobalContext(testCtx);
Code language: JavaScript (javascript)
Context Generator

A context generator is a callback that returns a self describing JSON, representing a context. They are evaluated each time an event is sent, hence they meet the case where we would like to send a context based on event payload.

GlobalContext testCtx = new ContextGenerator() { @Override public SelfDescribingJson generate(TrackerPayload payload, String eventType, String eventSchema) { return new SelfDescribingJson("iglu:com.acme/test_event/jsonschema/1-0-0"); } @Override public String tag() { return "testCtx"; } }; Tracker.instance().addGlobalContext(testCtx);
Code language: JavaScript (javascript)

Conditional Context Providers

A conditional context provider is used when a global context only needs to be sent for certain events. Whereas context primitives are sent with every event without exception.

Filter Provider

A Filter Provider is used to discriminate between events so we can attach global contexts only to certain events.

A Filter Provider has a callback, filter, returning a boolean which determines the events that this context primitive(s) will be added.

ContextPrimitive primitive = new SelfDescribingJson("iglu:com.acme/test_event/jsonschema/1-0-0"); GlobalContext testCtx = new FilterProvider("test-tag", new ContextFilter() { @Override public boolean filter(TrackerPayload payload, String eventType, String eventSchema) { return eventType.equals("se"); } }, primitive); Tracker.instance().addGlobalContext(testCtx);
Code language: JavaScript (javascript)
Ruleset Provider

A Ruleset Provider is used when you want to attach a global context to certain events based on the schema URI.

A Ruleset Provider has a RuleSet which has an allow list and a deny list. Both lists contain Iglu URIs which can be modified based on some syntactic rules.

In this example, the Ruleset Provider will attach the context primitive to events with the schema iglu:com.acme.*/*/jsonschema/*-*-*, but not to*/jsonschema/*-*-*.

ContextPrimitive primitive = new SelfDescribingJson("iglu:com.acme/test_event/jsonschema/1-0-0"); RuleSet ruleSet = new RuleSet("iglu:com.acme.*/*/jsonschema/*-*-*", "*/jsonschema/*-*-*"); GlobalContext testCtx = new RuleSetProvider("ruleSetExample", ruleSet, primitive); Tracker.instance().addGlobalContext(testCtx);
Code language: JavaScript (javascript)
Ruleset format

RuleSet’s rules are the strings used to match against certain schemas, such as iglu:com.acme/*/jsonschema/*-*-*.

They follow the same five-part format as an Iglu URI:


with the exception that a wildcard can be used in an allowed fashion to refer to all applying cases.

The parts of a rule are wildcarded with certain guidelines:

  • asterisks cannot be used for the protocol (i.e. schemas always start with iglu:).
  • version matching must be specified like so: *-*-*, where any part of the versioning can be defined, e.g. 1-*-*, but only sequential parts are to be wildcarded, e.g. 1-*-1 is invalid but 1-*-* is valid.
  • at least two parts parts: com.acme.* is valid, while com.* is not.
  • vendors cannot be defined with non-wildcarded parts between wildcarded parts: com.acme.*.marketing.* is invalid, while com.acme.*.* is valid

API Reference

For documentation detailing the entire Android tracking SDK, please refer to the API reference found here.

If you’d like to learn more about Snowplow BDP you can book a demo with our team, or if you’d prefer, you can try Snowplow technology for yourself quickly and easily.