iOS 9, Swift 2.0 , Xcode and testing

Question

I am planning to learn to develop iOS apps. I'll most probably be learning Objective-C only for now and would like to develop some actual apps for iOS.

Now, with the launch of Swift 2.0, will Objective-C apps still run on iOS9 ? Also, is it possible to test run an Objective-C app on your phone like mentioned here ? https://developer.apple.com/xcode/ Or is this facility available only for apps written in Swift?

Does Swift allow me to do everything that Objective-C does?

Any further advide or guidance for what should I know before enrolling for the course will be appreciated to help me judge things better.

Answer 1

Swift is still just the second language. All Cocoa frameworks are written in C or Obj-C (maybe the new ones in iOS 9 are written in Swift).

The language in which an application is written doesn't matter, the code is compiled into the same machine code, so yes, Obj-C apps will continue to run and many developers won't bother with Swift. Apps that have been already written will not have to be rewritten to Swift (with some exceptions).

Swift won't allow you to do absolutely everything that Obj-C does but it will allow you to do almost everything and the code will be probably more robust, considering that Swift is more modern language with stronger typing than Obj-C. If you are a beginner, you won't probably find any problematic use case.