protocols

问题 I have a protocol protocol SomeProtocol { func method() } and its implementation extension SomeProtocol {func method(){--implementation--}} In build target i have a class confirming to this protocol class SomeClass: SomeProtocol { func doSomething() { method() } } What i want is i want to have a different implementation of the protocol method in my test target, in my XCTest file. For that what i did was i extended the SomeClass and wrote my implementation there. extension SomeClass {func

问题 I've read the online docs about formal and informal protocols on Apple's documentation site, but I missed the point about informal protocols. I mean, a class cannot conform to an informal protocol, it conforms to it by default since informal protocols are almost always categories of the NSObject class. If you want to implement an informal protocol, you must redeclare the methods you want to implement in your interface file. Another class cannot check if you conform to the informal protocol

问题 I am working through an iOS swift Tetris tutorial* and have it completed and working. But I am puzzled about one particular aspect - the Hashable protocol. The function: class Block: Hashable, Printable { [...] var hashValue: Int { return self.column ^ self.row } Rows go 0..9, and Columns 0..20. The notes says of this function "We return the exclusive-or of our row and column properties to generate a unique integer for each Block.". But my understanding is that 0^1 would be the same as 1^0,

问题 Why doesn't this compile in Swift 1.2? protocol Proto { static var name : String {get set} } struct Struct : Proto { static var name : String = "name" } (In Swift 1.1, just substitute class for static inside the protocol declaration. Same problem.) The compiler complains that I'm not conforming to the protocol. But why am I not? It's easy to prove that the static property name in Struct is both readable and writable, so I've satisfied the spirit of the protocol, surely. I have some additional

问题 I'm trying to send information between two Container Views in Swift , through a delegate and I keep getting unwrapping error when performing the protocol function. my story board layout topContainerViewController.swift import UIKit protocol topContainerDelegate{ func send(text:String) } class topContainerViewController: UIViewController { var delegate: topContainerDelegate! = nil @IBOutlet var textField: UITextField! override func viewDidLoad() { super.viewDidLoad() } @IBAction func

问题 How should I design my message protocol so that I distinguish between user data and termination of the message. For example I take input from user to send it to client over TCP/IP, now the client-side needs to know the length of message, what I thought that I use some kind of termination by which the client recognizes that message end has been reached? How do I something like this in C++. I'm using Windows sockets 回答1: A reasonably common strategy for application-specific protocols is,

问题 I've got a protocol: protocol Adjustable: Equatable { associatedtype T var id: String { get set } var value: T { get set } init(id: String, value: T) } And a struct that conforms to it: struct Adjustment: Adjustable { static func == (lhs: Adjustment, rhs: Adjustment) -> Bool { return lhs.id == rhs.id } typealias T = CGFloat var id: String var value: T } And I'm building a wrapper class that behaves like a Set to handle an ordered list of these properties: struct AdjustmentSet { var

问题 One way I came up with is to make a protocol that other Enum must conform to. protocol StringRepresentable { var rawValue: String { get } } struct Endpoint { enum User: String, StringRepresentable { case Login = "/user/login" case Register = "/user/register" } enum Item: String, StringRepresentable { case Like = "/item/like" case Buy = "/item/buy" } } func urlString(endpoint: StringRepresentable) -> String { return "http://www.example.com\(endpoint.rawValue)" } let userLoginEndpoint =

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:

问题 In this code I'm attempting to pass an array from one tab view to another using protocols. The method itself is a simple get method with one line returning an a mutableArray. Within it's own class it works, within this class it is not even called. - (void)viewDidLoad { [super viewDidLoad]; myLocationEntityArray = [[NSMutableArray alloc] initWithArray:[[self delegate] getMyLocationEntityArray]]; } The header file for the class receiving the data: #import <UIKit/UIKit.h> #import <MapKit/MapKit