IOS: Learning notes, Swift and objective-c mixed with a concise tutorial (reproduced)

Swift and objective-c A concise tutorial for mixing

Reprinted from: HTTPS://GITHUB.COM/LIFEDIM/SWIFTCASTS/TREE/MASTER/000_MIX_SWIFT_OBJC

I think many iOS developers know Swift, the biggest problem in the mind is how to apply Swift to the original project. Below I will briefly describe the mix of these 2 languages, which is referenced from the official document Using Swift with Cocoa and Objective-c, which is recommended for everyone to read.

Using the Objective-c class in Swift

• To create a new file (? +n) in Xcode6, select Swift, and then the system box prompts you to make sure that the Xxx-bridging-header.h file (XXX is your project name) is created at the same time.

  This automatically created Bridging-header.h file is a bridge between the Swift world and the Objective-c world . any custom objective-c classes that need to be used in swift files must first be introduced into this header file .

  Suppose the project name is TestSwift , where there is a Objective-c class note ( Note.m defined in):

    @interface Note:nsobject   -(void) log;   @end

  To refer to this class in Swift, you first need TestSwift-Bridging-Header.h to import the note in the file:

    #import " Note.h "

  You can then use the note in Swift code:

  class Viewcontroller:uiviewcontroller {      override  func viewdidload () {          Super.viewdidload ()          = Note ()          a.log ()      }  }

Using the Swift class in Objective-c

• To refer to the classes defined in the Swift file in the Objective-c file, you need to introduce a special header file in the Objective-c file: Xxx-swift.h, assuming the project name is TestSwift , So the header file that needs to be introduced is TestSwift-Swift.h :

  Suppose there is a book class (defined in the Book.swift file):

    Import Foundation  class  book:nsobject {      var title:string      init () {           "Defaultbook"      }      func log () {          println (self.title)      }  }

  In the objective-c file that needs to refer to the book class, first introduce the TestSwift-Swift.h header file (this file does not need to be created)

  #import " testswift-swift.h "

  Then you can use the book:

  New ]; [book log];

  In the end, the XXX-Swift.h file is not visible in the project (it is estimated to be generated automatically at compile time), and it is OK to follow Apple's established rules when using it.