protocol-extension

Swift protocol extension method dispatch with superclass and subclass

由 寵の児 提交于 2019-12-29 06:52:27
问题 I found an interesting behaviour which seems like a bug... Based on the behaviour described the following articles: https://medium.com/ios-os-x-development/swift-protocol-extension-method-dispatch-6a6bf270ba94 http://nomothetis.svbtle.com/the-ghost-of-swift-bugs-future The output is not what I expect, when I add SomeSuperclass , rather than directly adopting the protocol. protocol TheProtocol { func method1() } extension TheProtocol { func method1() { print("Called method1 from protocol

Swift 2: UITableViewDataSource protocol extension

由 a 夏天 提交于 2019-12-21 05:26:14
问题 I have been playing around with protocol extensions and I have a problem. Maybe what I want to achieve can’t be done. I have this playground: //: Playground - noun: a place where people can play import UIKit protocol ArrayContainer { typealias T var array: [T] { get } } class MyViewController: UIViewController, ArrayContainer, UITableViewDataSource { typealias T = String var array = ["I am", "an Array"] } extension UITableViewDataSource where Self: ArrayContainer { func

Swift property observer in protocol extension?

由 ﹥＞﹥吖頭↗ 提交于 2019-12-18 12:49:17
问题 Consider the following: protocol ViewControllable: class { typealias VM: ViewModellable var vm: VM! { get } func bind() } extension ViewControllable { var vm: VM! { didSet { bind() } } } I'm trying to observe vm property and call bind whenever it is injected. But this doesn't compile with error saying: Extensions may not contain stored properties which makes sense since protocol cannot enforce properties to be stored or computed . Is this possible to accomplish without introducing class

Protocol extension on an ObjC protocol

由 廉价感情. 提交于 2019-12-18 02:41:50
问题 I have an Objective-C protocol which is used by mostly objective-C objects and one or two Swift objects. I would like to extend the protocol in Swift and add 2 functions. One to register for a notification and another to handle the notification. If I add these func registerForPresetLoadedNotification() { NSNotificationCenter.defaultCenter().addObserver(self as AnyObject, selector: #selector(presetLoaded(_:)), name: kPresetLoadedNotificationName, object: nil) } func presetLoaded(notification:

How to set delegate in a protocol extension

由 我只是一个虾纸丫 提交于 2019-12-10 23:07:06
问题 I have multiple view controllers which shows same kind of cells. I want to set delegate in a protocol extension like this: class ProductsViewController: UIViewController, ProductShowcase { //other properties @IBOutlet weak var productCollectionView: UICollectionView! var dataSource: DataSource! override func viewDidLoad() { super.viewDidLoad() setupDataSource() setupCollectionView() } func didSelectProduct(product: Product) { print(product) } //other functions } protocol ProductShowcase:

Swift protocol extension implementing another protocol with shared associated type

由 笑着哭i 提交于 2019-12-08 19:36:24
问题 Consider the following: protocol Foo { typealias A func hello() -> A } protocol FooBar: Foo { func hi() -> A } extension FooBar { func hello() -> A { return hi() } } class FooBarClass: FooBar { typealias A = String func hi() -> String { return "hello world" } } This code compiles. But if I comment out explicit definition of associated type typealias A = String , then for some reason, swiftc fails to infer the type. I'm sensing this has to do with two protocols sharing the same associated type

Calling selector from protocol extension

由 三世轮回 提交于 2019-12-04 04:33:10
I'm building simple theme engine and would like have an extension which adds UISwipeGestureRecognizer to UIViewController Here is my code: protocol Themeable { func themeDidUpdate(currentTheme: Theme) -> Void } extension Themeable where Self: UIViewController { func switchCurrentTheme() { Theme.switchTheme() themeDidUpdate(Theme.currentTheme) } func addSwitchThemeGestureRecognizer() { let gestureRecognizer = UISwipeGestureRecognizer(target: self, action:#selector(Self.switchCurrentTheme)) gestureRecognizer.direction = .Down gestureRecognizer.numberOfTouchesRequired = 2 self.view

Swift 2 Protocol Extensions and Conformance for Objective-C Types

由 偶尔善良 提交于 2019-12-02 11:20:51
问题 I have a setup like this: @interface Model: NSManagedObject ... @end And a Swift protocol like this: @objc protocol Syncable { var uploadURL: String { get } var uploadParams: [String: AnyObject]? { get } func updateSyncState() throws } extension Syncable where Self: NSManagedObject { func updateSyncState() throws { ... /* default implementation */ ... } } In a new Swift file, I try to do this: extension Model: Syncable { var uploadURL: String { return "a url" } var uploadParams: [String:

Swift property observer in protocol extension?

由 别来无恙 提交于 2019-11-30 11:22:11
Consider the following: protocol ViewControllable: class { typealias VM: ViewModellable var vm: VM! { get } func bind() } extension ViewControllable { var vm: VM! { didSet { bind() } } } I'm trying to observe vm property and call bind whenever it is injected. But this doesn't compile with error saying: Extensions may not contain stored properties which makes sense since protocol cannot enforce properties to be stored or computed . Is this possible to accomplish without introducing class inheritance ? In other words, Can I observe the change of a property inside protocol extension? No, this is

Can Swift Method Defined on Extensions on Protocols Accessed in Objective-c

由 孤街醉人 提交于 2019-11-30 00:38:02
问题 Is it possible to call methods defined in a protocol extension in Swift from Objective-C? For example: protocol Product { var price:Int { get } var priceString:String { get } } extension Product { var priceString:String { get { return "$\(price)" } } } class IceCream : Product { var price:Int { get { return 2 } } } The price string of an instance of IceCream is '$2' and can be accessed in Swift, however the method is not visible in Objective-C. The compiler throws the error 'No visible
订阅 protocol-extension