[Radar](/) abstracts away cross-platform differences between location services on iOS and Android, allowing you to add location tracking and geofencing to your apps with just a few lines of code. In this playbook, we explain how Radar can power your location-aware hacks. You will learn how to: - Create geofences for your campus, buildings on your campus, and more - Install the Radar SDK in your iOS or Android app - Change the app experience when a user is inside a geofence - Trigger a push notification when a user enters or exits a geofence - And more ![https://s3.amazonaws.com/io.radar.blog/playbooks/student-hackathon/photo.jpg](https://s3.amazonaws.com/io.radar.blog/playbooks/student-hackathon/photo.jpg) ## Step 1: Create geofences Geofences represent custom regions or places monitored in your project. Depending on your use case, a geofence might represent your campus, buildings on your campus, and so on. Let's create some geofences! First, sign up for a Radar account [here](/students). To create a geofence via the dashboard, go to the [Geofences page](/dashboard/geofences) and click the *New* button. You specify the metadata for geofences when you create them, including the *tag* (an optional group for the geofence, e.g., `building`), *external ID* (an optional ID for the geofence, e.g., `123`), and *description* (a display name for the geofence, e.g., `Building #123`). Start by searching for an address or place. Enter a description, optional tag, optional external ID, and optional metadata. Choose *circle* to draw a circle geofence, or *polygon* to draw a polygon geofence. Click *Create* to create the geofence. For example, we can create the following geofences: - `Duke University` (*tag* `campus` and *external ID*`duke`) - `Perkins Library` (*tag* `building` and *external ID* `library`) - `Cameron Indoor Stadium` (*tag* `building` and *external ID* `basketball`) ![https://s3.amazonaws.com/io.radar.blog/playbooks/student-hackathon/geofences.gif](https://s3.amazonaws.com/io.radar.blog/playbooks/student-hackathon/geofences.gif) ## Step 2: Install the SDK To use the geofences, let's install the SDK! For iOS, follow the documentation [here](/documentation/sdk#ios). To start: - [Configure your project](/documentation/sdk#ios-configure), adding location permission strings to your `Info.plist` - [Add the SDK to your project](/documentation/sdk#ios-add) with CocoaPods, with Carthage, or manually - [Request location permissions](/documentation/sdk#ios-permissions) - [Initialize the SDK](/documentation/sdk#ios-initialize) with your publishable API key, found on the [Settings page](/dashboard/settings) After following these steps, your `AppDelegate` class should look like this: ```swift import UIKit import RadarSDK @UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate, RadarDelegate { let locationManager = CLLocationManager() func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool { // request permissions locationManager.requestAlwaysAuthorization() // initialize SDK (replace with your publishable API key) Radar.initialize(publishableKey: "prj_test_pk_...") // todo in steps 3 and 4 } } ``` For Android, follow the documentation [here](/documentation/sdk#android). To start: - [Configure your project](/documentation/sdk#ios-configure), adding location permissions to your manifest - [Add the SDK to your project](/documentation/sdk#android-add) with Gradle - [Request location permissions](/documentation/sdk#android-permissions) - [Initialize the SDK](/documentation/sdk#android-initialize) with your publishable API key, found on the [Settings page](/dashboard/settings) After following these steps, your `MainActivity` class should look like this: ```kotlin import android.Manifest import android.os.Build import android.os.Bundle import androidx.appcompat.app.AppCompatActivity import androidx.core.app.ActivityCompat import io.radar.sdk.Radar class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) // request permissions if (Build.VERSION.SDK_INT >= 23) { val requestCode = 0 if (Build.VERSION.SDK_INT >= 29) { ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_BACKGROUND_LOCATION), requestCode) } else { ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.ACCESS_FINE_LOCATION), requestCode) } } // initialize SDK (replace with your publishable API key) Radar.initialize("prj_test_pk_...") // todo in steps 3 and 4 } } ``` ## Step 3: Change the app experience when a user is inside a geofence With geofences created and the SDK installed, we can now start adding location-aware features to our app! You can call `trackOnce()` to check if a user is inside a geofence when the app is in the foreground. Learn more about foreground tracking [on iOS](https://radar.io/documentation/sdk#ios-foreground) and [on Android](https://radar.io/documentation/sdk#android-foreground). For example, to unlock a feature only when a user is on campus, on iOS: ```swift Radar.trackOnce { (status, location, events, user) in user?.geofences?.forEach { (geofence) in if geofence.tag == "campus" { // user is on campus, unlock feature } } } ``` On Android: ```kotlin Radar.trackOnce { status, location, events, user -> user?.geofences?.forEach { geofence -> if (geofence.tag == "campus") { // user is on campus, unlock feature } } } ``` Check the [Users page](/dashboard/users) and [Events page](/dashboard/events) to verify that tracking is working. If you don't see a user or don't see events, check the status in the callback. ![https://s3.amazonaws.com/io.radar.blog/playbooks/student-hackathon/user.png](https://s3.amazonaws.com/io.radar.blog/playbooks/student-hackathon/user.png) ## Step 4: Trigger a push notification when a user enters or exits a geofence You can also call `startTracking()` to listen for geofence entry and exit events when the app is in the background. Learn more about background tracking [on iOS](https://radar.io/documentation/sdk#ios-background) and [on Android](https://radar.io/documentation/sdk#android-background). Assuming you have configured your project properly, the SDK will wake up while the user is moving (usually every 3-5 minutes), then shut down when the user stops (usually within 5-10 minutes). To save battery, the SDK will not wake up when stopped, and the user must move at least 100 meters from a stop (sometimes more) to wake up the SDK. To listen for events, set a `RadarDelegate` on iOS and a `RadarReceiver` on Android. For example, to start tracking and trigger a notification when a user enters the library, on iOS: ```swift import UIKit import RadarSDK @UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate, RadarDelegate { let locationManager = CLLocationManager() func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool { // request permissions locationManager.requestAlwaysAuthorization() // initialize SDK (replace with your publishable API key) Radar.initialize(publishableKey: "prj_test_pk_...") Radar.setDelegate(self) // start tracking let trackingOptions = RadarTrackingOptions() trackingOptions.priority = .responsiveness trackingOptions.offline = .replayStopped trackingOptions.sync = .all Radar.startTracking(trackingOptions) } func didReceiveEvents(_ events: [RadarEvent], user: RadarUser) { events.forEach { (event) in if event.type == .userEnteredGeofence && event.geofence?.tag == "building" && event.geofence?.externalId == "library" { // user entered library, show notification } } } } ``` On Android: ```xml

``` ```kotlin import android.Manifest import android.os.Build import android.os.Bundle import androidx.appcompat.app.AppCompatActivity import androidx.core.app.ActivityCompat import io.radar.sdk.Radar class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) // request permissions if (Build.VERSION.SDK_INT >= 23) { val requestCode = 0 if (Build.VERSION.SDK_INT >= 29) { ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_BACKGROUND_LOCATION), requestCode) } else { ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.ACCESS_FINE_LOCATION), requestCode) } } // initialize SDK (replace with your publishable API key) Radar.initialize("prj_test_pk_...") // start tracking val trackingOptions : RadarTrackingOptions = RadarTrackingOptions.Builder() .priority(RadarTrackingPriority.RESPONSIVENESS) .offline(RadarTrackingOffline.REPLAY_STOPPED) .sync(RadarTrackingSync.ALL) .build() Radar.startTracking(trackingOptions) } } ``` ```kotlin import io.radar.sdk.Radar import io.radar.sdk.RadarReceiver import io.radar.sdk.model.RadarEvent import io.radar.sdk.model.RadarUser class MyRadarReceiver : RadarReceiver() { override fun onEventsReceived(context: Context, events: Array, user: RadarUser) { events.forEach { event -> if (event.type == RadarEventType.USER_ENTERED_GEOFENCE && event.geofence?.tag == "building" && event.geofence?.externalId == "library") { // user entered library, show notification } } } } ``` ## What's next? Try creating more geofences or creating a [webhook](https://radar.io/documentation/integrations#event-integrations-webhooks) to receive events server-side. The possibilities are endless. We can't wait to see what you'll build with Radar!

Radar student hackathon playbook

It’s time to build