There are a couple of vector tile basemaps that appear to have issues in Runtime (100.2 or 100.3), but work fine in ArcGIS Pro. The problem is that certain vector tile layers/basemaps with a little transparency show the blank, grey-gridded background behind them (see below.)
I am wanting to use the Charted Territory basemap in Runtime . I've modded your GITHUB sample (arcgis-runtime-samples) under 'Layers/ArcGisVectorTiledLayer' as shown below and the resulting image is also below. The same result occurs if I use the direct .json ref to the layer (https://www.arcgis.com/sharing/rest/content/items/1c365daf37a744fbad748b67aa69dac8/resources/styles/...)
Does anyone know any fixes for this?
The style has the country polygons authored with transparency. It's meant to be used as an overlay on top of a basemap to add the color to the underlying map. So what you're seeing is expected.
You can see that effect in the online viewer:
Try and open the above link and change the basemap and you'll see how it adds the color to the underlying basemap.
You can turn off the lines on the background grid on the MapView.BackgroundGrid property or add a basemap.
Thanks Morton. After my post i realized that the Pro and Runtime backgrounds defaulted differently (white vs grey with grid). I did not realize i could change that background and had overlooked that option to do so. Thanks!