Swift 2 in Production

Talk held at our local user group, http://mobilemaultaschen.de

Transcript

1. Swift 2 In Production
2. New Stuff ☞ guard ♥♥♥ ☞ #available() ♥ ☞ Protocol Extensions ♥♥ ☞ SDK ♥ ☞ Error Handling " ☞ defer "
3. guard ☞ no more pyramid of doom optionals if let a = a { if let b = b { if let c = c { fn(a, b, c) } } }
4. guard ☞ better, but still pretty unreadable ☞ still too much indentation if let a = a, let b = b, let c = c { fn(a, b, c) }
5. guard guard let a = a else { Log.Error("a is required at this point.") return } guard let b = b else { Log.Error("b is required at this point.") return } guard let c = c else { Log.Error("c is required at this point.") return }
6. #available() let iOS9 = NSOperatingSystemVersion( majorVersion: 9, minorVersion: 0, patchVersion: 0) if NSProcessInfo().isOperatingSystemAtLeastVersion(iOS9) { // Stack views ! }
7. #available() if #available(iOS 9, *) { // Stack views ! } else { // Stack views " } @available(iOS 9, *) class MyStackView: UIStackView {}
8. Protocol extensions ☞ replace base class ☞ default behaviour ☞ decoration/composition ☞ adopt in enum/struct/class
9. Protocol extensions @objc public protocol Bookmarkable { var remoteIdentifier: Int { get } } extension Bookmarkable { public var remoteIdentifier: Int { return -1 } }
10. Protocol Extensions extension NSManagedObject: Bookmarkable { public var remoteIdentifier: Int { guard respondsToSelector("remoteID") else { Log.Warn("\(self) doesn't respond to 'remoteID'") return -1 } guard let remoteID = valueForKey("remoteID") as? NSNumber else { Log.Error("'remoteID' didn't return a number.") return -1 } return Int(remoteID.integerValue) } }
11. Error handling ☞ good ol' times var readError: NSError? let contents = NSString(contentsOfFile: filePath, encoding: NSUTF8StringEncoding, error: &readError) if readError != nil { // Oh no, something went wrong }
12. Error handling ☞ the new way: let contents: NSString? do { contents = try NSString(contentsOfFile: filePath, encoding: NSUTF8StringEncoding) } catch let error as NSError { print(error) }
13. Error handling ☞ define your error types enum FileError: ErrorType { case NoSuchFile case IsDirectory } func readFile(atPath path: String) throws { var isDir: ObjCBool = false guard NSFileManager().fileExistsAtPath(path, isDirectory: &isDir) else { throw FileError.NoSuchFile } guard isDir.boolValue == false else { throw FileError.IsDirectory } }
14. Error handling do { try readFile(atPath: "~/.vim") } catch FileError.NoSuchFile { print("No such file") } catch FileError.IsDirectory { print("Item at path is a directory") }
15. defer func writeToStream(something: StreamWriteable) { let stream = openStream() defer { closeStream(stream) } something.write(toStream: stream) // don't worry about closing it // even when errors occur }
16. Mixed Projects ☞ Setup ☞ bridging Header (only app targets) ☞ module map (framework targets) ☞ module name (requires DEFINES_MODULE=YES)
17. Mixed Projects ☞ Ignore Xcode "Can't build module XYZ" ☞ Ignore missing auto completion when importing "ModuleName- Swift.h"
18. Debugger ☞ Can't jump into ObjC file from Swift code ☞ Can't jump into Swift file from ObjC code
19. Dependencies ☞ Dependency management, iOS >= 8.0 ☞ CocoaPods → use_frameworks! ☞ Carthage ☞ Dependency management, iOS < 8.0 ☞ Include source files ☞ git submodules !
20. Other Annoyances ☞ Quick open from Swift file ☞ NO REFACTORING!!!111elf !
21. Future? Objective-C == techn. dept?