Nalwaya Abhishek Nalwaya & Paul Akshat Paul 
RubyMotion iOS Develoment Essentials [EPUB ebook] 

This is a step-by-step book that builds on your knowledge by adding to an example app over the course of each chapter. Each topic uses example code that can be compiled and tested to show how things work practically instead of just telling you the theory. Complicated tasks are broken down into easy to follow steps with clear explanations of what each line of code is doing.Whether you are a novice to i OS development or looking for a simpler alternative to Objective-C; with Ruby Motion i OS Development Essentials, you will become a pro at writing great i OS apps