Esri global map showing instead of map at requested location - Xamarin iOS and Android app

Question

We have a Xamarin-based app that we have migrated from the Esri for Startups program to the Esri Developer program.  As part of that migration, we needed to change our app to use the new Esri License Key and Esri Api Keys.  That part of the migration was straightforward and is working fine.  But the part that has not been working reliably is the request of the Esri map for presentation.  At random times, our map page, that is supposed to show the user's current location, instead shows the default Esri Global Map.   Please see the attached video for an example of this behavior.  At the end of the video, the Esri global map is shown. Here is the code we use to create the Esri map:
 A few things of note:* the Anglr app is a Xamarin native app for iOS and Android
* this occurs with more frequency on Android than iOS
* with this same code, we never saw this behavior when we were part of the Startups program
* we are using 100.13.0 version of the ArcGISRuntime nugets for both platforms

I've been banging on this one for a few weeks now, any help/suggestions/comments are greatly appreciated!

-Tom Klempay (Senior Software Engineer, AnglerLabs)

esri.mp4

AnglrTech · Answer

Hi Nathan,

Want to give you a quick update.  I was able to incorporate much of what you suggested and in my dev testing, things are really looking good on both iOS and Android.  Our next step is to push my changes into our test environment.  We're rolling that out today.  I'll let you know how it goes.

-Tom

NathanCastle1 · Answer

Tom,

Yes, ideally viewpoint should be set after the map is added to the MapView. That may require a small amount of refactoring to break this code into two parts, one to create the map, another to call `mapView.SetViewpoint` or `mapView.SetViewpointAsync`. Alternatively, you might be able to follow the pattern in `AddGraphicsOverlays` to interact with the MapView.

Since the GetMap is already an async Task, you should be able to insert `await _map.LoadAsync` before returning the map. That will ensure the map is loaded before it is added to the map. If you explicitly load the map by calling `_map.LoadAsync` before returning, you can then check `_map.LoadStatus` rather than setting up an event. Although if you are already making the change to calling SetViewpoint on the MapView, then you should only need the explicit loading step if you want to do error handling.

Updated code might look something like the following:

try
{
    var basemap = await _currentMapStyle.ToEsri();

_map = new Map(basemap);

await _map.LoadAsync();

_mapView.Map = _map; // Or alternatively do this in a separate method

AddGraphicsOverlays();

await _mapView.SetViewpointAsync(initialLatitude, initialLongitude, _defaultZoom);
}
catch //... error handling - explicit loading of map should throw exceptions that you can catch

AnglrTech · Answer

Nathan,

re: your bullet points

* Are you saying to set the Viewpoint after a successful MapLoaded status is returned?
* Our app makes use of Esri maps and Google maps so we have an internal enum to manage the different map types between the two platforms.  The _currentMapStyle.ToEsri method is a mapping function from an internal enum value to the associated Esri Basemap.  
* I've been wondering if there was a timing element to this problem.  It will take me some work to change the return of the map for that but that makes a lot of sense to me.

Thanks much for your suggestions!

Regards,

-Tom