topic .Net Xamarin - Map Shows Blank in .NET Maps SDK Questions

.Net Xamarin - Map Shows Blank

JimFiddes — Tue, 13 Jun 2017 17:01:58 GMT

Hey Everyone

I'm in the process of building a mobile app and within it I have a map plugin that is utilizing Esri.ArcGISRuntime.Xamarin.Android nuget package (version 100). I have created a C# class which implements a LinearLayout and on Initialize, I construct my Esri.ArcGISRuntime.UI.Controls.MapView and call AddView(_myMapView) followed up with a load layer method that constructs a map consuming a Streets basemap.

Everything compiles and the layout appears in my app and I see the Powered by ESRI logo; however, nothing displays. The map appears black and no other code fires if I drag or pinch my finger over the control. I did wire up the LoadStatusChanged event for my map and I do achieve a loaded status, again nothing is visible.

Thoughts?

Re: .Net Xamarin Forms - Map Shows Blank

dotMorten_esri — Tue, 13 Jun 2017 22:09:15 GMT

Could you share some code that shows how you are setting up the map?

Re: .Net Xamarin Forms - Map Shows Blank

JimFiddes — Wed, 14 Jun 2017 13:42:21 GMT

Hey there

Here is condensed code from my class:

public class MapControlView : LinearLayout
{
private readonly MapView _myMapView = new MapView();

#region Implementors
public MapControlView(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
{
Initialize();
}

public MapControlView(Context context) : base(context)
{
Initialize();
}

public MapControlView(Context context, IAttributeSet attrs) : base(context, attrs)
{
Initialize();
}

public MapControlView(Context context, IAttributeSet attrs, int defStyleAttr) : base(context, attrs, defStyleAttr)
{
Initialize();
}

public MapControlView(Context context, IAttributeSet attrs, int defStyleAttr, int defStyleRes) : base(context, attrs, defStyleAttr, defStyleRes)
{
Initialize();
}
#endregion

private void Initialize()
{
_myMapView.NavigationCompleted += MyMapView_OnNavigationCompleted;
AddView(_myMapView);
LoadLayers();
}

private void LoadLayers()
{
var mdsMap = new Map(Basemap.CreateImagery());
mdsMap.LoadStatusChanged += MdsMap_LoadStatusChanged;
_myMapView.Map = mdsMap;
}

private void MdsMap_LoadStatusChanged(object sender, global::Esri.ArcGISRuntime.LoadStatusEventArgs e)
{
if (_mapReadyForUse) return;

if (e.Status.Equals(LoadStatus.Loaded))
{
_uiContext.Post(x =>{(sender as Map).LoadStatusChanged -= MdsMap_LoadStatusChanged;

_mapReadyForUse = true;
MapReady?.Invoke();
}, null);
}
}
}//end of class

Re: .Net Xamarin - Map Shows Blank

JimFiddes — Mon, 19 Jun 2017 15:27:30 GMT

Any input on why my map appears blank but still shows Powered by ESRI?

Re: .Net Xamarin - Map Shows Blank

dotMorten_esri — Mon, 19 Jun 2017 15:50:14 GMT

The two parts are two separate parts to the MapView control. The "Powered by ESRI" text is rendered by the Android Label classes, whereas the map itself is rendered directly by OpenGL and won't start doing rendering until the map is properly loaded.

So it indicates the mapview control is there and loaded, but there's no map it can render, or issues with generating the OpenGL context.

Is the MapView.DrawStatusChanged ever fired?

Re: .Net Xamarin - Map Shows Blank

JimFiddes — Tue, 20 Jun 2017 15:31:55 GMT

Yes the MapView.DrawStatusChanged event fires as well as the Map.LoadStatusChanged event fires. No exceptions or warnings appear.

Re: .Net Xamarin - Map Shows Blank

dotMorten_esri — Tue, 20 Jun 2017 15:46:18 GMT

And what are the draw statuses of the layers that are being reported?

Re: .Net Xamarin - Map Shows Blank

JimFiddes — Tue, 20 Jun 2017 15:53:21 GMT

From what I can see, the map gets a status of loaded in the end and the basemap appears to load without issue. The only thing I do see is that the draw status of the map view is always in progress and never gets to completed.

Re: .Net Xamarin - Map Shows Blank

dotMorten_esri — Tue, 20 Jun 2017 15:54:36 GMT

Does this map/mapview work outside your custom LinearLayout?

Re: .Net Xamarin - Map Shows Blank

JimFiddes — Tue, 20 Jun 2017 16:04:05 GMT

So....it appears the issue of the map view never getting a completed status in the DrawStatusChanged event was due to my Post method. In our .net code for windows we Post to another thread to say the map is ready and in the Xamarin Android side, this is not required. By commenting out the post method, my MapReady event is then triggered within the View containing this linear layout which then in turns allows the map view to complete its drawing event.

This thread can now be closed but it is good to know that a MapControlView can be managed within a class that implements a linear layout.

Re: .Net Xamarin - Map Shows Blank

JimFiddes — Tue, 20 Jun 2017 16:05:03 GMT

Thanks for posting ideas on what to check, it was of great help in finding out I created my own troubles.