topic Re: Strange tile request in ArcGIS Runtime SDK for Android Questions

Strange tile request

MikeC — Tue, 10 Jun 2014 01:18:29 GMT

In the HelloWorld example, the map access service.arcisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer. Even I did not add the layer to the MapView it always made a request to /ArcGIS/rest/services/World_Street_Map/MapServer/tile/-1/0/0.

If I have 10 different layers in the MapView, it will got 10 requests for the -1/0/0. You know that tile does not exists, so why this thing happens?

Re: Strange tile request

ShellyGill1 — Tue, 10 Jun 2014 07:29:27 GMT

Hi,

I understand that is the first request to a service based on a tiled layer - information in the response allows allows the MapView to work out what to show for missing tiles in that specific tiled layer - some services have a specific 'no data' tile to show, whereas others return a 404 error for a missing tile. The MapView can then work out which option it's dealing with.

Hope this helps some,

Re: Strange tile request

MikeC — Mon, 16 Jun 2014 07:10:07 GMT

Understood.

Can the missing tiles (no data files / 404) be initialized at the first time it encounters the hit? Most people may never get the missing tile hit throughout his own session. But the current implementation force people try the thing they may never face in every single layers.

Re: Strange tile request

ShellyGill1 — Tue, 17 Jun 2014 07:58:09 GMT

From what I know, the information about how to handle no data tiles is needed at layer initialization time, before more tile requests are sent, so that an appropriate handler can be set for every subsequent genuine tile request. If the no data tile were not assessed in advance, more work would need to happen on every genuine tile request, which would obviously impact efficiency. Having said that, I wouldn't expect the initial request to be a lengthy operation, it happens only once per layer initialization, and I would not expect this to surface to the end user in any way including with any perceptible delay in layer initialization - so if you are finding that end users are aware of this specific request in any way (not just from LogCat), then let us know.

Thanks,