Thank you once more
@oparra for these suggestions.
Unfortunately, I am not competent enough to dive into taking bits of cofe from disparate libraries, even from other platforms such as J, and adapt them.
MapAx may be a good solution, but developer did not share his source code, so it cannot be instructive to me.
My only chance is to find a dedicated, stable, comprehensive library that does (most of) the job...
B4XMaps does most of the job but doesn't appear to be able to load offline/custom tiles unless cached ones.
OSMDroid might be such a library, but is seems difficult to know if
- Can OsmDroid load offline tiles?
- What tile files should be produced and where should they be stored?
- How should they be loaded?
It seems that original OSMDroid 6.x does all this but it's not available in B4X platform, while it is not known (to me) if the older (and apparently abandoned) OsmDroid 4.x wrapped for B4X can do it.
Of course I could go back to Android Studio and use OSMDroid 6.x, but B4X seems much more user friendly to me...
Thank you for your continued help!