Design+Code is an excellent resource for learning about building iOS apps. It's half design tutorials and half coding tutorials. It first caught my attention for the terrific tutorials for the Mac app Sketch.1 I purchased the entire "book" immediately and it is all top quality. If you think the Design+Code Web site is gorgeous just wait until you see the tutorial content.
The next chapter Design with Swift is now available and starts with a good discussion of Web vs. Native
Seriously, Sketch is out of this world. I've made things with Sketch in 10 minutes that I couldn't do in hours with other apps. ↩