Navigation simulation with on-demand map download

In this guide you will learn how to simulate online navigation along a route while downloading map data on demand.

Setup

First, get an API key token, see the Getting Started guide.

Download the Maps & Navigation SDK for Android archive file

Download the DownloadingOnboardMapSimulation project archive file or clone the project with Git

See the Configure Android Example guide.

Run the example

In Android Studio, from the File menu, select Sync Project with Gradle Files

An android device should be connected via USB cable.

Press SHIFT+F10 to compile, install and run the example on the android device.

Simulates online navigation along a route while downloading map data on demand.

How it works

You can open the MainActivity.kt file to see how the route computation and simulated navigation are set up.

<uses-permission android:name="android.permission.INTERNET" />

Note that, in AndroidManifest.xml, the INTERNET permission is present, as this example downloads online map data on demand.

Downloaded map data is stored on the device in a directory such as this: /sdcard/Android/data/com.generalmagic.examplename/files/Data/Maps/.

In the class MainActivity : AppCompatActivity(), an instance of each of the following is created: a navigation listener val navigationListener: NavigationListener a progress listener for the route computation val routingProgressListener a content listener to download required maps val contentListener and the override fun onCreate() to instantiate and initialize the various panels used for computing the route and for navigation along the route, and then it calls startSimulation().

val contentListPair = contentStore.getStoreContentList(EContentType.RoadMap)
?: return@execute
for (map in contentListPair.first) {
val mapName = map.name ?: continue
if (mapName.compareTo(MAP_NAME, true) != 0)
// searching another map
    continue
if (map.isCompleted())
// already downloaded
    return@execute
// Define a listener to the progress of the map download action.
val downloadProgressListener = ProgressListener.create(
    onStarted = {
        progressBar.visibility = View.VISIBLE
        showToast("Started downloading $mapName.")
    },
    onCompleted = { errorCode, _ ->
        progressBar.visibility = View.GONE
        if (errorCode == GemError.NoError) {
            showToast("$mapName was downloaded.")
            onOnboardMapReady()
        }
    }
)
// Start downloading the first map item.
map.asyncDownload(
    downloadProgressListener,
    GemSdk.EDataSavePolicy.UseDefault,
    true
)
break
}

In the contentListener() val, we have the above check, which looks at the online maps available on the server, to make sure that the map required for the location where the route is to be computed or where simulated navigation is to take place, is available on the server, if not already downloaded, and downloads it.

val localMaps =
    contentStore.getLocalContentList(EContentType.RoadMap)
    ?: return@onSdkInitSucceeded
var mapFound = false
for (map in localMaps) {
    val mapName = map.name ?: continue
    if (mapName.compareTo(MAP_NAME, true) != 0)
    // searching another map
        continue
    if
        (!map.isCompleted()) {
        // can't continue with incomplete map.
        break
    }
    mapFound = true
}
// Defines an action that should be done when the the sdk had been loaded.
if (mapFound)
    onOnboardMapReady()

In the onCreate() function, we have the above check, which looks at the local/downloaded/offline maps, to make sure that the map required for the location where the route is to be computed or where simulated navigation is to take place, is already downloaded, or if it is still in the process of downloading, then give it more time so it can finish.

private fun startSimulation() = SdkCall.execute {
     val waypoints = arrayListOf(
         Landmark("Luxembourg", 49.61588784436375, 6.135843869736401),
         Landmark("Mersch", 49.74785494642988, 6.103323786692679)
     )
     navigationService.startSimulation(
         waypoints,
         navigationListener,
         routingProgressListener
     )
 }

The startSimulation() function first instantiates a list of 2 waypoints, one for the departure location and one for the destination; there can be more than 2 waypoints in a route, but not less than 2. These 2 waypoints are hardcoded here, and the locations can be anywhere on the planet, as the required country map will be downloaded.

fun Route.getEta() function to get the estimated time of arrival for this route.

fun Route.getRtt() function to get the route time for this route.

fun Route.getRtd() function to get the route distance for this route.

Android Examples

Maps SDK for Android Examples can be downloaded or cloned with Git