Type-safe Oriented Programming

Talk da 17ª edição do CocoaHeads RJ sobre Type-safe Oriented Programming

Transcript

1. Type-safe oriented programming: Fuja das Strings! Diego Ventura iOS Developer @ OLX Brasil
2. E no início eram os xibs…
3. E no início eram os xibs… • XIB - XML Interface Builder / Mac OS X Interface Builder • File > New File > View • File’s owner (UIViewController)
4. E no início eram os xibs… Objective-C Swift [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil]; ViewController(nibName: "ViewController", bundle: nil)
5. E depois veio o Storyboard…
6. E depois veio o Storyboard… • Vários Xibs num mesmo arquivo • Set subclass na ViewController • Segues facilitaram a vida dos devs
7. E depois veio o Storyboard… Objective-C Swift UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil]; YourViewControllerClass *viewController = [storyboard instantiateViewControllerWithIdentifier:@"ViewController"]; ViewController(nibName: "ViewController", bundle: nil)
8. Só tem um problema TODOS eles usam Strings
9. Strings são ruins • Não possui verificação em compile time • Em times grandes, é mais complicado ter uma padronização • Favorece, e muito, o typo! (i.e MyTypoViewControler)
10. E aí como faz?
11. E aí como faz?
12. E aí como faz?
13. Type-safe w/ Extensions extension UIViewController { private class var nibNameIdentifier: String { return NSStringFromClass(self).componentsSeparatedByString(".").last! } class func instantiateFromXib() -> Self { return self.init(nibName: nibNameIdentifier, bundle: nil) } } let welcomeViewController = WelcomeViewController.instantiateFromXib()
14. Type-safe w/ Extensions
15. Type-safe w/ Extensions and Generics //Register nib let nib = UINib(nibName: "MyCustomCellNib", bundle: nil) tableView.registerNib(nib, forCellReuseIdentifier: "MyCustomCellIdentifier") //Dequeue cell var cell = tableView.dequeueReusableCellWithIdentifier(“MyCustomCellIdentifier", forIndexPath: indexPath) as MyCell!
16. Type-safe w/ Extensions and Generics
17. Type-safe w/ Extensions and Generics protocol ReusableViewProtocol { static var reuseIdentifier: String { get } } extension ReusableViewProtocol where Self: UIView { static var reuseIdentifier: String { return NSStringFromClass(self) } }
18. Type-safe w/ Extensions and Generics protocol ReusableNibLoadableProtocol: class { static var nibName: String { get } } extension ReusableNibLoadableProtocol where Self: UIView { static var nibName: String { return NSStringFromClass(self).componentsSeparatedByString(".").last! } }
19. Type-safe w/ Extensions and Generics extension UITableView { func registerClass<T: UITableViewCell where T: ReusableViewProtocol>(_: T.Type) { registerClass(T.self, forCellReuseIdentifier: T.reuseIdentifier) } func registerNib<T: UITableViewCell where T: ReusableViewProtocol, T: ReusableNibLoadableProtocol>(_: T.Type) { let bundle = NSBundle(forClass: T.self) let nib = UINib(nibName: T.nibName, bundle: bundle) registerNib(nib, forCellReuseIdentifier: T.reuseIdentifier) } }
20. Demo
21. Perguntas
22. Obrigado! Diego Ventura diego.ventura@me.com @venturadiego https://github.com/diegoventura @ PS: Estou vendendo um MacBook Air