WOW

that looks amazing !!!
This looks like even better than I thought would ever be possible with Spider Basic.
Finally, maybe there will be a chance to write the perfect motorcycle navigation app I was dreaming of to do for years.
Do you already do the routing and do navigate within your app or is it more like displaying a picture?
Maybe you will publish your code sometimes?
2.- I don't understand this point, but sounds difficult to me.
I don't think it's really so difficult. I think it's just a thing how to get the permission for the app to open it's UI above others.
The rest should be like programming a normal App/UI.
Many smartphone nowadays allow split the screen, so you can put two apps at once. May be a workaround.
That's not really a practical Option, because this will limit the other Apps (like navigation App) too much.
But a CarPlay or Android Auto Version (where the App could be next to e.g. Google Maps or Kurviger.de) would be nice indeed.
It's an app to follow gpx routes with indications turn by turn on offroad environments, so the voice indications are curve based, because I don't use roads, only narrow trails.
For Trail-Navigation I use the APP OsmAND. Originally it's made for mountain-bikers, walkers and climbers, so it can rout even the smallest trails. It can use several differente types of Map-Data. It also does the voice indication curved based, like yours.
It's really worth to have a look at ...BUT: Imho it has a terrible (totally overloaded and not intuitive) UI and it's not very stable (especially when you use it with Android Auto).
So, please keep on the great and promising work on your App and show the competitors (like OsmAND) how it's done right.
