What is the fastest way to learn Objective-C for experienced programmers?

I came from Java, C, PHP and Ruby before doing iOS and the learning curve was still massive. This is partly because Objective-C is very different compared to the more conventional languages, but mostly because Objective-C is tightly integrated with the Cocoa (Touch) framework, and the tools around it. You can learn the basics of Objective-C in about a week, but learning how to use all the tools and libraries in Cocoa can take months- or years for overly curious types like myself. I made my first "Hello World" 3 years ago, and only now am I beginning to fully understand the ins and outs of iOS. The problem with cramming for an iOS/OS X interview is you are going to have to cram Objective-C, Cocoa (Touch for iOS), Xcode- and that's only the tip of the iceberg. Most shops will also require you be up on your Git (which you hopefully are by now), native and third party libraries/frameworks (see https://github.com/AFNetworking/AFNetworking), and TDD. The questions you will encounter could range from Objective-C questions like "When is an autoreleased object's retain count decremented?" or a Cocoa question like "How is NSNotifcationCenter similar/different from KVO?" to an Xcode question- "How do you enable auto-layout in an app previously targeted for iOS 4?" or even an Instruments question, "How can you find which code segment is hanging the main thread?" Your potential employer will likely quiz you on some iOS 7/Xcode 5 details since those are about to become the new standard. To play with these, you'll need to sign up (and pay $99) for an https://developer.apple.com/register/index.action account to download the betas. I don't want to scare you off from Apple development, because it's pretty awesome and a bunch of fun once you get the hang of it. But it is definitely not one of those things you can fake-til-you-make. TL;DR - It will take a while. Read a lot of books, read a lot of blogs, look at other people's code, make your own apps. http://www.amazon.com/Objective-C-Programming-Ranch-Guide-Guides/dp/0321706285/ref=sr_1_2?ie=UTF8&qid=1378602736&sr=8-2&keywords=objective-c http://www.amazon.com/Cocoa-Design-Patterns-Erik-Buck/dp/0321535022/ http://www.amazon.com/Xcode-Developer-Reference-Richard-Wentk/dp/111800759X/ref=sr_1_6?ie=UTF8&qid=1378603257&sr=8-6&keywords=xcode Apple's https://developer.apple.com/library/ios/navigation/#section=Resource%20Types&topic=Sample%20Code. http://nshipster.com/ blog - A blog by Mattt Thompson, a local legend of iOS. http://www.cocoawithlove.com/ - another blog, another Matt, another local legend. http://www.raywenderlich.com/ - A blog gone tutorial site. Covers a good bit of beginner/intermediate development tools/tricks. https://github.com/trending?l=objective-c - to see what other developers are currently thinking about.

Learn the language I would read a pocket reference for the language and take notes for the key concepts. Writing down stuff will clarify your ideas and help you remember. “Programming with Objective-C” from Apple is a good start. Then repeat the material using a book focused on Objective-C. Get a $10 account on Safari O'Reilly, it will grant you access to 5 books. Identify key technologies Find out what is the following ARC, KVC, KVO, NSCoder, NSOperation, NSNotification, NSRunLoop, NSError, NSString, NSURLConnection. GCD, dispatch_get_main_queue, dispatch_once, dispatch_async, dispatch_sync. UIApplication, UIApplicationDelegate, UIView, UIWindow, CALayer, UITableView, UICollectionView, UIAlertView. What is a controller? UIKit, Core Data, Core Animation, Quartz, MapKit, AFNetworking. Xcode, Instruments, NSZombieEnabled, XIB, NIB, AutoLayout. Read interview questions You'll find them on Google. But of course, a good interviewer will make open questions and notice what your experience is. Example: http://blackpixel.com/blog/2013/04/interview-questions-for-ios-and-mac-developers-1.html Print these questions, go for a walk, and explain them to your imaginary friend. Do the same with the words above. Read books If you still have time, I like http://my.safaribooksonline.com/book/programming/iphone/9780321706485 by Joe Conway & Aaron Hillegass http://shop.oreilly.com/product/0636920029717.do by Matt Neuburg (also http://www.apeth.com/iOSBook/) http://www.amazon.com/iOS-Core-Animation-Techniques-ebook/dp/B00EHJCORC by Nick Lockwood http://my.safaribooksonline.com/book/programming/iphone/9780321670168 by Erica Sadun http://pragprog.com/titles/amiphd/iphone-sdk-development by Bill Dudney If you try GUI applications concentrate on small tasks. For example, create a "Navigation-based  Application template" project, and try to understand the hierarchy. Then add  features like, create a cell, delete a cell, sort them, click a cell to push a second screen.

Getting yourself familiar with the Cocoa API is probably most useful.I learnt Objective-C by just building an app (for learning purposes, nothing anyone really needs), like displaying some publicly available data in a table or view etc. Perhaps you could do the same and just look up answers to the problems you run into on the way.