protocols

问题 I have made delegate protocol within two view controllers. but the delegate method doesn't call on my code snippet. what is the reason for that. I couldn't find out the issue kindly post your suggestions to relive this issue. Main View controller class ViewController: UIViewController, testDelegateMethod { override func viewDidLoad() { super.viewDidLoad() let vw = testViewController() vw.delegateTest = self let push = self.storyboard?.instantiateViewController(withIdentifier:

问题 I can use generic protocols just fine, but am trying to grasp the reasoning behind some limitations of generic protocols. Example: internal protocol ArchEnemyable { var archEnemy: Self? { get } } internal final class Humanoid: ArchEnemyable { internal var archEnemy: Humanoid? // is the adoption to Self, works only when class is final internal init(otherOne pOtherOne: Humanoid?) { self.archEnemy = pOtherOne } } I do not find any example where it would not work, when it is not final. Do one of

问题 I am rather new to object-oriented programming and I am attempting to wrap my head around protocols, delegates, and polymorphism. I recently watched a training video that promoted that when you have two classes that are similar with similar method implementations, a protocol is the best solution for achieving this elegantly. That makes sense. However, some additional research has led me to discover polymorphism and it sounds like that is also a preferred approach, whereas you could simply use

问题 I am trying to use a protocol to pass an array from one class to another. protocol PinsArray { var dataArray: [LocationPost] {get set} } When I am trying to create a delegate in class, which should receive it does not work. I cannot access the property var delegate = PinsArray.self Like this: delegate.dataArray It says that "instance member 'dataArray' cannot be used on type PinArray" So what do I do wrong? 回答1: You are assigning the type of PinsArray to delegate instead of assigning an

问题 Remote Desktop Protocol version 6.1 changed the way RDP sessions are handled (making session 0, which previously meant "console session", into a non-interactive session). I need to be able to figure out from within my program how to determine just what version of the RD protocol is being used on the current RDP session. Nothing I can find in the Windows Terminal Services API, however, seems to give me the protocol version. 回答1: the WTSClientBuildNumber attribute in the WTS_INFO_CLASS contains

问题 I just found another way to make a great use of protocols and protocol extensions in Swift by extending the Optional protocol to add a function so I can provide default values. I wrote a blog post about this here: https://janthielemann.de/random-stuff/providing-default-values-optional-string-empty-optional-string-swift-3-1/ The gist of the post is that I needed a clean and easy way to provide default values for optional String which are nil or empty. To do this, I created a Emptyable protocol

问题 I'm trying to achieve something similar to how Swift utilizes the CodableKeys protocol set on an enumeration defined within a class that implements Codable . In my case, the class is CommandHandler and the enumeration is CommandIds and it doesn't require on code-gen from the compiler as the enum will always be explicitly specified. Here's a simplified version of what I'm after... protocol CommandId{} protocol CommandHandler{ associatedtype CommandIds : CommandId, RawRepresentable } class

问题 I'm trying to achieve something similar to how Swift utilizes the CodableKeys protocol set on an enumeration defined within a class that implements Codable . In my case, the class is CommandHandler and the enumeration is CommandIds and it doesn't require on code-gen from the compiler as the enum will always be explicitly specified. Here's a simplified version of what I'm after... protocol CommandId{} protocol CommandHandler{ associatedtype CommandIds : CommandId, RawRepresentable } class

问题 Is it possible to declare variable in @protocol? Just to force programmers to add those variable in implementing class's(classes which implements this protocol) header and implementation? Thanks 回答1: Short answer: No, it isn't possible to do that . You can enforce the availability of methods and properties at most. 回答2: You can't declare ivars in @protocol s but you can force the conforming class to implement an accessor and a mutator, which sounds like what you're getting at. For example:

问题 I'm a new in iOS, and I have trouble in implementing @protocol so sorry if you think this is an easy thing.. i've been searching around stackoverflow.com, the webs and also try uncle Google for a while and I decided to ask here... The main idea is calling a MyViewController from TopViewController and do flip animation I Start with creating the protocols.. // This is my Delegate header // MyViewController.h @protocol MyViewControllerlDelegate - (void) myViewControllerDidFinish; @end @interface