swift-protocols

问题 I’m trying to come up with an protocol-oriented MVVM for my tableviewcells. I have lots of them. my viewModel protocol PlainTableViewCellModelType { var backgroundColor : UIColor {get} var textColor: UIColor {get} var titleFont : UIFont {get } var accessoryType : UITableViewCellAccessoryType {get} var textLabelNumberOfLines: Int {get} } my view protocol PlainTableViewCellType{ associatedtype viewModel : PlainTableViewCellModelType func setupUI(forViewModel viewModel: viewModel) } my class

问题 [SOLVED] Solution When created a Xib File , I hadn't deleted the start UIView. Whereas I had to delete this view and after add new CollectionViewCell in this xib. Reference: IBAction inside UITableViewCell not called in iOS 9 I use this structure so many times.When I write this delegate with using StoryBoard , it works properly but now it's not. Where is my mistake when use the xib files? print(indexpath) doesn't work! import UIKit class SearchVC: UIViewController { var searchUid:String? var

问题 I was wondering if it is possible in Swift to make a type conform to a protocol, so that I can treat the type itself as conforming to a protocol the way one normally treats instances as conforming to a protocol. Example code: protocol P { func f() } class C where C.self: P { // Not actual code static func f() { print("Because C.f: ()->() exists, C.self should satisfy the protocol.") } } 来源： https://stackoverflow.com/questions/42286462/make-a-type-itself-not-its-instances-conform-to-a-protocol

问题 I was wondering if it is possible in Swift to make a type conform to a protocol, so that I can treat the type itself as conforming to a protocol the way one normally treats instances as conforming to a protocol. Example code: protocol P { func f() } class C where C.self: P { // Not actual code static func f() { print("Because C.f: ()->() exists, C.self should satisfy the protocol.") } } 来源： https://stackoverflow.com/questions/42286462/make-a-type-itself-not-its-instances-conform-to-a-protocol

问题 Swift protocols can provide default implementations for functions and computed properties by adding extensions to them. I've done that plenty of times. It is my understanding that the default implementation is only used as a "fallback" : It's executed when a type conforms to the protocol but doesn't provide its own implementation. At least that's how I read The Swift Programming Language guide: If a conforming type provides its own implementation of a required method or property, that

问题 Swift protocols can provide default implementations for functions and computed properties by adding extensions to them. I've done that plenty of times. It is my understanding that the default implementation is only used as a "fallback" : It's executed when a type conforms to the protocol but doesn't provide its own implementation. At least that's how I read The Swift Programming Language guide: If a conforming type provides its own implementation of a required method or property, that

问题 Suppose I create a protocol and structure for a Column of homogeneously typed data: protocol Columnizable { associatedtype Item var name: String { get } var values: [Item] { get } } struct Column<T>: Columnizable { var name: String var values = [T]() } I would like to create a Protocol extension that allows Numeric to have an average function that could compute the average of values if the type conforms to Numeric protocol- for instance, namely Double and Int extension Columnizable where Item

问题 This is a basic example of creating an array of protocols with associated types using type erasure: protocol ProtocolA { associatedtype T func doSomething() -> T } struct AnyProtocolA<T>: ProtocolA { private let _doSomething: (() -> T) init<U: ProtocolA>(someProtocolA: U) where U.T == T { _doSomething = someProtocolA.doSomething } func doSomething() -> T { return _doSomething() } } Creating an array of them isn't hard: let x: [AnyProtocolA<Any>] = [] Is there any way way I can create an array

问题 Is it possible to provide confirming protocol in generic functions of another protocol? I tried make it work like this, but it's impossible, or I made some mistakes. My code: protocol DataModelProtocol { associatedtype ObjectProtocol: Protocol func fetchObjects<T: ObjectProtocol>() -> [T]? func fetch<T: ObjectProtocol>(object: T) -> T? func delete<T: ObjectProtocol>(allObjectOf type: T.Type) func insert<T: ObjectProtocol>(_ object: T) func save<T: ObjectProtocol>(_ object: T) func update<T:

问题 I tried to cast a swift protocol array as any array, but failed. protocol SomeProtocol: class{ } class SomeClass: NSObject, SomeProtocol{ } let protocolArray: [SomeProtocol] = [SomeClass()] let value: Any? = protocolArray if let _ = value as? [SomeProtocol]{ print("type check successed") //could enter this line } Above code could work as expected. However, my problem is, I have a lot of protocols, and I don't want to check them one by one. It is not friendly to add new protocol. Is there any