Ask HN: What are your favorite resources for learning iOS development?

I know there are some resources from Apple, but my experience with their online getting started wasn't the best. Overall, the way it was written didn't fit with me. It was a dry, step-by-step instruction cookbook with little explanation behind deeper concepts (presumably to make the getting started fast).

How did you learn native-iOS coding? What would you recommend to a developer who wants to get into iOS dev? (i.e. resources presuming previous dev knowledge of loops, control flow, OOP, collections, etc. are OK, even preferable).