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Android Integration Guide

Nextome Android SDK Cover

How to include

  1. Add our repositories in root build.gradle:
      allprojects {
     repositories {
       maven {
           url ""
           credentials {
               username = $USERNAME
               password = $PASSWORD
       maven { url '' }

Contact Nextome to receive a valid username/password to access our repository.

  1. Add SDK dependency in app’s build.gradle:

Check latest released version here


Optional Dependencies

If you plan to display a live map to the user, add our Flutter MapView plugin:

  1. Add Flutter repository in root build.gradle:
      allprojects {
     repositories {
       maven {url '' }
  2. Add SDK dependency in app’s build.gradle:

Getting started

Whitelabel app

A complete example of an Android App build on top on Nextome’s SDK is available here.

Required permissions

To run, Nextome SDK requires the following permissions:

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION" />

Those are required to:

  • Contact the backend server;
  • Activate and manage Bluetooth beacon scan;
  • Run as a foreground service for background mode;
  • Access Bluetooth API (location)

SDK Builder

To use Nextome SDK for Android, a builder is available with some options you can customize.

The basic configuration only needs your application context, the given developer key, the secret and bundle.

nextomeSdk = NextomePhoenixSdk().Builder(applicationContext)

Other optional parameters are also available. Here’s a list of the customization available and a short description of them.

Scanner parameters

The longer you wait between scans, the longer it will take to detect a beacon. And the more reduce the length of the scan, the more likely it is that you might miss an advertisement from an beacon.

You can optionally customize scan period and scan duration:


sets a time in millis for the bluetooth beacon scan duration when in foreground mode.

Default value is 1000 ms


sets a time in millis to wait between bluetooth scans when in foreground mode.

Default value is 250 ms.


sets a time in millis for the bluetooth beacon scan duration when in backgorund mode.

Default value is 1000 ms


sets a time in millis to wait between bluetooth scans when in background mode.

Default value is 250 ms.

Other optional parameters


ignore beacons below a custom RSSI threshold.

Default value is -75.


keeps in memory a cache of n RSSI entries in time for each beacon to more accurately compute user position.

Default value is 12


Sets the algorithm for localization. Choises are LINEAR_SVD, NON_LINEAR_DA, PARTICLE.

Default value is LINEAR_SVD


This allows you to skip the search for venue phase and automatically download resurces of a specific venue when Nextome starts.

With this, you can force your app to open only your venue and download venue resurces even if you’re not in range of your venue beacons.


This allows you to automatically send positions to Nextome server and track monitor devices realtime on the web manager.

Default value is false


This allows you to ignore when user exits and enters again in a event radius in a short time span. For example, if timeout is set to 60 seconds, the same event onEnter after onExit is received will be not triggered again for at least for 1 minute.

Default value is 0 seconds (realtime).

Start localization

To start localization, call:


If you want Nextome to keep track of user indoor position also while the phone screen is off or your app is in background, call this method instead:

nextomeSdk.startForegroundService(serviceCode, notification)

In this case, a service code and a notification is also required. The ongoing notification will be displayed while Nextome SDK runs in background mode.

Observe user position

Nextome SDK offers two different observers to notify user position.

  • nextomeSdk.localizationLiveData will notify indoor user position,with info about:
  • x, y coordinates of the user relative to the indoor map;
  • mapId and floorId of the current user position;
  • nextomeSdk.outdoorLocalizationLiveData will notify outdoor user position, with its latitude and longitde.

Usage example:

nextomeSdk.localizationLiveData.observe(this, {
    log("Got indoor position (${it.x}, ${it.y}), on map ${it.mapId} in floor ${it.floorId})")

nextomeSdk.outdoorLocalizationLiveData.observe(this, {
    log("Got outdoor position (${}, ${it.lng})")

Observe SDK status

It’s possibile to observe the current state the Nextome SDK, in the localization process.

You can use this data to start initializing the map or showing messages to the users and update your UI accordingly.


The exposed information are:

  • isOutdoor: indicates if the SDK is running in outdoor or indoor mode;
  • tiles: local path on device of map tiles. You can use this info to initialize a map (for example, our Flutter map) to show the map to the user;
  • mapHeight: the height in pixel of the currentmap;
  • mapWidth: the width in pixel of the current map;
  • venueResources: resources associated with the venue (list of maps, pois, events…);
  • state Nextome SDK state.

Nextome SDK State

Nextome State is a simple state machine that can have those states:

  • STARTED: Nextome has been correctly initialized and it’s ready to scan beacons;
  • SEARCH_VENUE: Nextome is currently scanning nearby beacons to determine in which venue the user is; If the SDK is stuck here, you’re probably outdoor.
  • GET_PACKET: Nextome knows the venue of the user and it’s downloading from the server the associated resources (Maps, POIs, Patches…);
  • FIND_FLOOR: All the venue resoruces have been downloaded. Nextome is now computing in which floor the user is;
  • RUNNING: Nextome SDK is computing user positions. You can observe live user location using the observer nextomeSdk.locationLiveData;


  • Map tiles, venueResources, height and width are only available in the RUNNING state (when Nextome has recognized or has been forced the venue and the map where the user is); Otherwhise, they return null.
  • If the user changes floor, the SDK will resume from FIND_FLOOR state.
  • If the user goes outdoor, the SDK will switch to SEARCH_VENUE state until a new indoor beacon is detected.

Get venue resources

You can optionally ask the SDK for the local resources downloaded with your venue (those resources include maps, pois, beacons events…). There are two ways of doing this.

In the state observer:

    nextomeSdk.stateLiveData.observe(this, {
        when (it.state) {
            NextomePhoenixState.RUNNING -> {
                val poiList = it.venueResources.allPois
                val poiOfTheCurrentFloor = it.venueResources.getPoisByMapId(it.mapId)
                val mapsInTheVenue = it.venueResources.maps
            else -> { }

as a single method call:

    val resources = nextomeSdk.state.venueResources

Note that you can only retreive resources when Nextome SDK State is RUNNING. Otherwhise, nextomeSdk.state.valueResources will return a null object.


nextomeSdk.stateLiveData.observe(this, {
    if (it.isOutdoor) {
    } else {

    when (it.state) {
        NextomePhoenixState.STARTED -> {
            updateState("Sdk Started")
        NextomePhoenixState.SEARCH_VENUE -> {
            updateState("Searching Venue...")
        NextomePhoenixState.GET_PACKET -> {
            updateState("Downloading packet...")
        NextomePhoenixState.FIND_FLOOR -> {
            updateState("Finding current Floor...")
        NextomePhoenixState.RUNNING -> {
            updateState("Loading map...")

            with(it) {
                setIndoorMap(mapTilesUrl, mapHeight, mapWidth, venueResources.getPoisByMapId(mapId))

Observe SDK errors

You can be notified of SDK errors using the appropriate observer:

nextomeSdk.errorObservable.observe(this) {

Force a specific map

This is expecially useful when using the Flutter Map Module.

With this method you can force Nextome to show a specific map, indipendently from the user real indoor location.

When this method is called, Nextome will stop sending indoor location updates.

You can force a map using:


Nextome will immediatly fire a status change, localizing the user at the specified map and offering map information like tiles, height and width that you can pass to the map module.

When you’re done and you want to observe user real location again, call:



// Force map 42

nextomeSdk.stateLiveData.observe(this, {
    when (it.state) {
        NextomePhoenixState.RUNNING -> {
            with(it) {
                // After forcing the map, here you can pick tiles, height and width of map 42.
                setIndoorMap(mapTilesUrl, mapHeight, mapWidth, venueResources.getPoisByMapId(mapId))

Calcualte path

Nextome Sdk is able to calculate the shortest path between two points of the same venue.

The function takes (x, y) coordinates and map of the starting point and (x, y) coordinates and map of the destination point.

val path = nextomeSdk.findPath(
                startX.toInt(), startY.toInt(), startMapId,
                targetX.toInt(), targetY.toInt(), targetMapId)

The returned path is a list of ordered Vertex, that, for example, can be passed to the Flutter Map Module and displayed to the user (see the methods writtenbelow).

Observe events

Available from nexome-sdk > 0.4.0

If events are set up in your venue, you can observe when user enters or exits from event radius using those two observers:

    nextomeSdk.enterEventObservable.observe(this) { event ->
        Log.d("event_test", "Received on enter with data: ${}")

    nextomeSdk.exitEventObservable.observe(this) { event ->
        Log.d("event_test", "Received on exit with data: ${}")

Optionally, after exiting from event, it’s possible to set a timeout value in seconds before signaling that event again.

This allows you to ignore when user exits and enters again in a event radius in a short time span. For example, if timeout is set to 60 seconds, the same event onEnter after onExit is received will be not triggered again for at least for 1 minute.

If set to 0, Nextome SDK will signal onEnter and onExit event realtime.

    nextomeSdk = NextomePhoenixSdk().Builder(applicationContext)

Flutter Map Module

If you want, there’s an optional module build with Flutter that can show a live map of the indoor location of the user.

To use it, include the gradle dependency as written before in the How to include section.

Flutter Init

A little of boilerplate code is required to initialize and set up a channel between Flutter and the native app.

You can just paste this code and run it before showing the map to the user.

private fun initFlutter() {
    val appId = "com.nextome.test"
    val engine = FlutterEngine(this)

    // Start executing Dart code in the FlutterEngine.

    // Cache the pre-warmed FlutterEngine to be used later by FlutterFragment.
        .put(appId, engine)

    val fragmentManager: FragmentManager = supportFragmentManager

    // Attempt to find an existing FlutterFragment, in case this is not the
    // first time that onCreate() was run.
    flutterFragment = fragmentManager
        .findFragmentByTag(TAG_FLUTTER_FRAGMENT) as FlutterFragment?

    // Create and attach a FlutterFragment if one does not exist.
    if (flutterFragment == null) {
        var newFlutterFragment = FlutterFragment

        flutterFragment = newFlutterFragment


    channel = MethodChannel(engine.dartExecutor, appId)

Flutter Utils

An utility class is available to help you with Flutter operations. If you want to comunicate with Flutter, it’s suggested to include this class in your project.

Show a new indoor map

Once a map is available, pass the tiles local directory, height and width` of the map to Flutter:

private fun setIndoorMap(mapTilesUrl: String, mapHeight: Int, mapWidth: Int) {
        "$mapTilesUrl,$mapHeight,$mapWidth, 3")

Update user live position

When a new indoor user position is available, notify Flutter with:

private fun updatePositionOnFlutterMap(it: NextomePosition) {
    channel.invokeMethod("localPackageUrl", FlutterUtils.getLocalPackagePayload(mapTilesUrl, mapHeight, mapWidth))

Add a POI

You can add custom Point of Interest on the Flutter map using this method:

private fun showPoiOnMap(poiList: List<NextomePoi>) {
    channel.invokeMethod("POI", FlutterUtils.getPoiPayload(poiList))

Show a custom patch

You can show a path on the map using this method and passing a list of Vertex. You can automatically get the Vertext between a start and end point of the map using the appropriate method on the nextomeSdk:

private fun showPathOnMap(path: List<Vertex>) { 
    channel.invokeMethod("path", FlutterUtils.getPathPayload(path))

Observe events on Flutter Map

With this observer you can be notified of events on the Flutter map, for example, when the user decides to navigate to a POI.

private fun observeMapEvents() {
    channel.setMethodCallHandler { methodCall, _ ->
        // On POI "Navigate to" tapped
        if (methodCall.method == "poiData") {
            val poiSerialized = methodCall.arguments as String
            val poi = Gson().fromJson(poiSerialized,

            // Ex. calculate path to POI and show it to user
                lastPosition.x, lastPosition.y lastPosition.mapId,
                poi.x!!, poi.y!!,!!)

Show Center Position Fab

Available from flutter-map > 1.2.0

It’s possible to show an optional fab at the bottom right of the map. When clicked, the button will:

  • center the map on the user position;
  • follow the user position live on map;
  • rotate the map based on user compass;

To enable the button, use:

channel.invokeMethod("showCenterPositionFab", "true")

or, if you have imported our Flutter Utils:

    fabEnabled = true

Please note

The compass feature will only work if the app has the following permissions:

  • android.permission.INTERNET
  • android.permission.ACCESS_COARSE_LOCATION
  • android.permission.ACCESS_FINE_LOCATION

If those permissions are not denied, the navigation button will only follow user position without rotating.

Change user position icon

Available from flutter-map > 1.2.0

The default position icon is a blue dot. If you want to change the icon, you can load a remote resource from an url.

  channel.invokeMethod("customPositionResourceUrl", "")

or, if you’re imported our Flutter Utils:

      customPositionResourceUrl = ""

Debug tools

In case of necessity, Nextome SDK can write logs with useful info to a file. You can start writing logs with nextomeSdk.startLoggingOnFile(). Those logs can then be shared using nextomeSdk.stopAndShareLog(context). A new Intent will be fired with a share dialog that allows to export and save the logs with other apps.


A full working example app is available on this repository. Run the MapActivity to see Nextome Sdk in action. It also contains a seamless outdoor/indoor map integration using OpenStreetMap for outdoor and Nextome Flutter Map for indoor.

**© 2021 Nextome srl All Rights Reserved.**

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