WWDC2014_IntegratingSwiftWithObjectiveC.md

Integrating Swift With Objective-C

Introduction

• Swift is modern, type-safe, expressive, performant

• but Objective-C remains a first-class citizen

• Same design patterns, Cocoa APIs

• "We do not want you to rewrite or stop improving your existing code!"

• Should you use unowned or weak for delegates?

• To expose Objective-C to Swift, use a bridging header

  • MyApp-Bridging-Header.h

• To expose Swift to Objective-C, Xcode gives you a generated header

  • Generated as part of build process
  • #import "MyApp-Swift.h"

• In a framework target, everything in the umbrella header is exposed to Swift (no bridging header)

init(data: NSData, type: String) {
	self.data = data.copy() as NSData
	// copy returns an `AnyObject` so we nee`d to cast it
	self.type = type
}

init(coder aDecoder: NSCoder) {
	data = aDecoder.decodeObjectForKey("data") as NSData
	type = aDecoder.decodeObjectForKey("type") as NSString
}

@import

• If a framework was built with Xcode 6 and has the defined modules build setting turned on, you should use @import
• Not sure how frameworks play out with cocoapods?