# Utilize the User Context API

{% hint style="info" %}
Accessing some of the API classes that are mentioned on this page requires additional Sentiance SDK dependencies. See [this page](https://docs.sentiance.com/important-topics/appendix/on-device-features#user-current-context-information) for more information.
{% endhint %}

On this page, you can find examples of how to query the Sentiance SDK for the user's current context, and how to register to receive real time updates in your app, as the user's context changes.

### Query for the User's Current Context

{% tabs %}
{% tab title="iOS" %}

```swift
Sentiance.shared.requestUserContext { context, error in
    guard let context = context else {
        print("Error: \(error?.failureReason)")
        return
    }
    
    print("Recent events:")
    
    // Print the recent events
    context.events.forEach({ event in
        print("Event ID: \(event.eventId)")
        print("Started on: \(event.startDate)")
        print("Ended on: \(event.endDate)")
        
        if event.type == .inTransport {
            let transport =  event as! SENTTransportEvent
            
            print("Type: transport")
            print("Mode: \(toStringMode(transport.transportMode))")
            
            if let distance = transport.distanceInMeters {
                print("Distance: \(distance)")
            }
            
            print("Waypoints: \(transport.waypoints)")
            
        }
        else if event.type == .stationary {
            let stationary =  event as! SENTStationaryEvent
            
            print("Type: stationary")
            print("Location: \(stationary.location)")
            print("Venue: \(stationary.venue)")
        }
        else if event.type == .offTheGrid {
            print("Type: off-the-grid")
        }
        else {
            print("Type: unknown")
        }
        
        print("")
    })
    
    // Print the home & work locations, semantic time, and last known location
    print("Home venue: \(context.home)")
    print("Work venue: \(context.work)")
    print("Semantic time: \(toString(context.semanticTime))")
    print("Last known location: \(context.lastKnownLocation)")
    
    // Print the user's active segments
    print("Active segments:")
    
    context.activeSegments.forEach { segment in
        print("  Category: \(toString(segment.category))")
        print("  Subcategory: \(toString(segment.subcategory))")
        print("  Type: \(toString(segment.type))")
        print("  Start date: \(toString(segment.startDate))")
        print("  End date: \(toString(segment.endDate))")
        
        print("  Attributes: ")
        segment.attributes.forEach { attribute in
            print("    \(attribute.name): \(attribute.value)")
        }
    }
}
```

{% endtab %}

{% tab title="Android" %}

```kotlin
UserContextApi.getInstance(context).requestUserContext()
    .addOnFailureListener { error ->
        print ("User context retrieval failed with reason ${error.reason}")
    }
    .addOnSuccessListener { context ->

        // Print the recent events
        print("Recent events:")

        context.events.forEach { event ->
            print("Event ID: ${event.id}")
            print("Started on: ${event.startTime}")
            print("Ended on: ${event.endTime}")

            when (event.eventType) {
                EventType.IN_TRANSPORT -> {
                    val transport = event as TransportEvent!

                    print("Type: transport")
                    print("Mode: ${transport.transportMode}")

                    if (transport.distanceInMeters != null) {
                        print("Distance: ${transport.distanceInMeters}")
                    }

                    print("Waypoints: ${transport.waypoints}")
                }
                EventType.STATIONARY -> {
                    val stationary = event as StationaryEvent!

                    print("Type: stationary")
                    print("Location: ${stationary.location}")
                    print("Venue: ${stationary.venue}")
                }
                EventType.OFF_THE_GRID -> {
                    print("Type: off-the-grid")
                }
                else -> {
                    print("Type: unknown")
                }
            }
        }

        // Print the home & work locations, semantic time, and last known location
        print("Home venue: ${context.home}")
        print("Work venue: ${context.work}")
        print("Semantic time: ${context.semanticTime}")
        print("Last known location: ${context.lastKnownLocation}")

        // Print the user's active segments
        print("Active segments:")

        context.activeSegments.forEach { segment ->
            print("  Category: ${segment.category}")
            print("  Subcategory: ${segment.subcategory}")
            print("  Type: ${segment.type}")
            print("  Start date: ${segment.startTime}")
            print("  End date: ${segment.endTime}")

            print("  Attributes: ")
            segment.attributes.forEach { attribute ->
                print("    ${attribute.name}: ${attribute.value}")
            }
        }
    }
```

{% endtab %}

{% tab title="React Native" %}

```javascript
import SentianceUserContext from '@sentiance-react-native/user-context';

const context = await SentianceUserContext.requestUserContext();

// Print the recent events
for (const event of context.events) {
    console.log(`Event ID: ${event.id}`);
    console.log(`Started on: ${event.startTime}`);
    console.log(`Ended on: ${event.endTime}`);

    switch (event.type) {
        case 'IN_TRANSPORT':
            const transport = event;
            console.log('Type: transport');
            console.log(`Mode: ${transport.transportMode}`);

            if (transport.distance) {
                console.log(`Distance: ${transport.distance}`);
            }
            console.log(`Waypoints: ${JSON.stringify(transport.waypoints)}`);
            break;
        case 'STATIONARY':
            const stationary = event;
            console.log('Type: stationary');
            console.log(`Location: ${JSON.stringify(stationary.location)}`);
            console.log(`Venue: ${JSON.stringify(stationary.venue)}`);
            break;
        case 'OFF_THE_GRID':
            console.log('Type: off-the-grid');
            break;
        default:
            console.log('Type: unknown');
    }
}

// Print the home & work locations, semantic time, and last known location
console.log(`Home venue: ${JSON.stringify(context.home)}`)
console.log(`Work venue: ${JSON.stringify(context.work)}`)
console.log(`Semantic time: ${context.semanticTime}`)
console.log(`Last known location: ${JSON.stringify(context.lastKnownLocation)}`)

// Print the user's active segments
console.log('Active segments:')

for (const segment of context.activeSegments) {
    console.log(`  ID: ${segment.id}`)
    console.log(`  Category: ${segment.category}`)
    console.log(`  Subcategory: ${segment.subcategory}`)
    console.log(`  Type: ${segment.type}`)
    console.log(`  Start date: ${segment.startTime}`)
    console.log(`  End date: ${segment.endTime}`)

    console.log('  Attributes:')
    segment.attributes.forEach { attribute ->
        console.log(`    ${attribute.name}: ${attribute.value}`)
    }
}
```

{% endtab %}

{% tab title="Flutter" %}

```dart
import 'package:sentiance_user_context/sentiance_user_context.dart';
import 'package:sentiance_event_timeline/sentiance_event_timeline.dart';

final sentianceUserContext = SentianceUserContext();

void fetchUserContext() async {
  final context = await sentianceUserContext.requestUserContext();

  // Print the recent events
  for (final event in context.events) {
    print('Event ID: ${event.id}');
    print('Started on: ${event.startTimeMs}');
    print('Ended on: ${event.endTimeMs}');

    if (event is TransportEvent) {
      final transport = event;
      print('Type: transport');
      print('Mode: ${transport.transportMode}');
      print('Distance: ${transport.distance}');
      print('Waypoints: ${transport.waypoints}');
    } else if (event is StationaryEvent) {
      print('Type: stationary');
      print('Location: ${event.location}');
      print('Venue: ${event.venue}');
    } else if (event is OffTheGridEvent) {
      print('Type: off-the-grid');
    } else if (event is UnknownEvent) {
      print('Type: unknown');
    }
  }

  // Print the home & work locations, semantic time, and last known location
  print('Home venue: ${context.home}');
  print('Work venue: ${context.work}');
  print('Semantic time: ${context.semanticTime}');
  print('Last known location: ${context.lastKnownLocation}');

  // Print the user's active segments
  print('Active segments:');

  for (final segment in context.activeSegments) {
    print('  ID: ${segment.segmentId}');
    print('  Category: ${segment.category}');
    print('  Subcategory: ${segment.subcategory}');
    print('  Type: ${segment.type}');
    print('  Start date: ${segment.startTimeMs}');
    print('  End date: ${segment.endTimeMs}');

    print('  Attributes:');
    for (final attribute in segment.attributes.nonNulls) {
      print('    ${attribute.name}: ${attribute.value}');
    }
  }
}
```

{% endtab %}
{% endtabs %}

### Subscribe for User Context Updates

{% tabs %}
{% tab title="iOS" %}
{% code lineNumbers="true" %}

```swift
public class UserContextHandler: SENTUserContextDelegate {
    
    public func subscribe() {
        Sentiance.shared.userContextDelegate = self
    }    
        
    public func didUpdate(_ userContext: SENTUserContext, 
       forCriteriaMask criteriaMask: SENTUserContextUpdateCriteria) {
        
        // Check the updated criteria
        if criteriaMask.contains(.currentEvent) {
            print("The user's current event was updated")
        }
        if criteriaMask.contains(.visitedVenues) {
            print("The user's visited venue information was updated")
        }
        if criteriaMask.contains(.activeSegments) {
            print("The user's active segments were updated")
        }
       
        // Handle the updated context data (see the Query for the 
        // User's Current Context example above)
    }
}
```

{% endcode %}
{% endtab %}

{% tab title="Android" %}

```kotlin
UserContextApi.getInstance(context)
  .addUserContextUpdateListener { criteria, context ->
    // Check the updated criteria
    if (criteria.contains(UserContextUpdateCriteria.CURRENT_EVENT)) {
        print("The user's current event was updated")
    }
    if (criteria.contains(UserContextUpdateCriteria.VISITED_VENUES)) {
        print("The user's visited venue information was updated")
    }
    if (criteria.contains(UserContextUpdateCriteria.ACTIVE_SEGMENTS)) {
        print("The user's active segments were updated")
    }

    // Handle the updated context data (see the Query for the
    // User's Current Context example above)
}
```

{% endtab %}

{% tab title="React Native" %}
To get user context updates even when your app is in the background, place the following code inside your app's entrypoint **index.js** file. If you're only interested in these updates when your app is foregrounded, place this code inside the appropriate UI code instead.

```javascript
import {addUserContextUpdateListener} from "@sentiance-react-native/user-context";

// If you're subscribing to event updates only in the foreground, make sure
// to call subscription.remove() inside your component's componentWillUnmount() function
const subscription = addUserContextUpdateListener(userContext => {
    // Handle the updated context data (see the Query for the
    // User's Current Context example above)
});
```

{% endtab %}

{% tab title="Flutter" %}
Create a **background.dart** file under your project's **lib** folder with the following code:

{% code title="background.dart" %}

```dart
import 'package:sentiance_user_context/sentiance_user_context.dart';

@pragma('vm:entry-point')
void registerUserContextListener() async {
  WidgetsFlutterBinding.ensureInitialized();

  SentianceUserContext.registerUserContextUpdateListener((criteria, context) {
    // Check the updated criteria
    if (criteria.contains(UserContextUpdateCriteria.currentEvent)) {
      print("The user's current event was updated");
    }
    if (criteria.contains(UserContextUpdateCriteria.visitedVenues)) {
      print("The user's visited venue information was updated");
    }
    if (criteria.contains(UserContextUpdateCriteria.activeSegments)) {
      print("The user's active segments were updated");
    }

    // Handle the updated context data (see the Query for the
    // User's Current Context example above)
  });
}
```

{% endcode %}

Add the following code, depending on your target platform. 

For **iOS**, add the following to your app delegate class:

{% code title="AppDelegate.swift" %}

```swift
import Flutter
import sentiance_user_context

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {

    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
    
        // Other code
        
        SentianceUserContextPlugin.initializeListener(
            withEntryPoint: "registerUserContextListener",
            libraryURI: "package:your_app_package_name/background.dart"
        )
        
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }
}
```

{% endcode %}

For **Android**, add this code to your custom application class:

{% code title="MainApplication.kt" %}

```kotlin
import android.app.Application
import com.sentiance.user_context_plugin.UserContextPlugin

class MainApplication : Application() {
    override fun onCreate() {
        super.onCreate()
        
        // Other code

        val dartLibrary = "package:your_app_package_name/background.dart"
        UserContextPlugin.initializeListener(this, dartLibrary, "registerUserContextListener")
    }
}
```

{% endcode %}

If you're calling other APIs from the user context SDK or other 3rd party plugin APIs inside your `registerUserContextListener` Dart function, then you need to register these plugins with the Sentiance SDK. See [this](https://docs.sentiance.com/a-complete-integration/flutter-quick-start/registering-bg-listeners) for more details.
{% endtab %}
{% endtabs %}