当委托字段未被称为“委托”时，实现“`DelegateProxy`”(RxSwift/RxCocoa)

Question

我需要一些DelegateProxy实现方面的帮助。具体来说，当委托字段的名称与简单的delegate不同时，实现它的正确方法是什么？例如在SKPhysicsContactDelegate中，它被称为contactDelegate。我试着定义一个计算值delegate，但是它并没有达到https://github.com/maxvol/RxSpriteKit/blob/master/Proxy/RxSKPhysicsContactDelegateProxy.swift的目的。

它在"DelegateProxy has no factory of <PKPhysicsWorld: 0x280b18990>. Implement DelegateProxy subclass for <PKPhysicsWorld: 0x280b18990> first."中失败--也许它甚至与委托字段名无关，但这是我能找到的与正常工作的代理的唯一不同之处。

更新： Ha！我只是注意到错误消息说的是PKPhysicsWorld，而不是SKPhysicsWorld。所以我的假设是，这与object in DelegateProxyFactory.createProxy是一个PKPhysicsWorld而不是SKPhysicsWorld和_factories[ObjectIdentifier(mirror.subjectType)]返回nil的事实有关。

Answer 1

之所以会出现此错误，是因为您的registerKnownImplementations()函数没有运行。

以下要点应该有效：https://gist.github.com/dtartaglia/9f1f937628504ca56dbb1aac7d91df2b

代码也在下面，但要点可以保持最新：

//
//  SKPhysicsWorld+Rx.swift
//
//  Created by Daniel Tartaglia on 21 Jan 2019.
//  Copyright © 2019 Daniel Tartaglia. MIT License.
//

import RxSwift
import SpriteKit

public
extension Reactive where Base: SKPhysicsWorld {

    var didBegin: Observable<SKPhysicsContact> {
        return Observable.create { observer in
            physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
            let uuid = UUID()
            if let (delegate, beginners, enders) = physicsContatctDelegates[self.base] {
                var new = beginners
                new[uuid] = observer
                physicsContatctDelegates[self.base] = (delegate, new, enders)
            }
            else {
                let delegate = PhysicsContactDelegate(for: self.base)
                self.base.contactDelegate = delegate
                physicsContatctDelegates[self.base] = (delegate, [uuid: observer], [:])
            }

            return Disposables.create {
                physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
                let (delegate, beginners, enders) = physicsContatctDelegates[self.base]!
                var new = beginners
                new.removeValue(forKey: uuid)
                if new.isEmpty && enders.isEmpty {
                    physicsContatctDelegates.removeValue(forKey: self.base)
                }
                else {
                    physicsContatctDelegates[self.base] = (delegate, new, enders)
                }
            }
        }
    }

    var didEnd: Observable<SKPhysicsContact> {
        return Observable.create { observer in
            physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
            let uuid = UUID()
            if let (delegate, beginners, enders) = physicsContatctDelegates[self.base] {
                var new = enders
                new[uuid] = observer
                physicsContatctDelegates[self.base] = (delegate, beginners, new)
            }
            else {
                let delegate = PhysicsContactDelegate(for: self.base)
                self.base.contactDelegate = delegate
                physicsContatctDelegates[self.base] = (delegate, [:], [uuid: observer])
            }

            return Disposables.create {
                physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
                let (delegate, beginners, enders) = physicsContatctDelegates[self.base]!
                var new = enders
                new.removeValue(forKey: uuid)
                if new.isEmpty && enders.isEmpty {
                    physicsContatctDelegates.removeValue(forKey: self.base)
                }
                else {
                    physicsContatctDelegates[self.base] = (delegate, beginners, new)
                }
            }
        }
    }
}

private
class PhysicsContactDelegate: NSObject, SKPhysicsContactDelegate {

    init(for world: SKPhysicsWorld) {
        self.world = world
        super.init()
    }

    func didBegin(_ contact: SKPhysicsContact) {
        physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
        let (_, beginners, _) = physicsContatctDelegates[world]!
        for each in beginners.values {
            each.onNext(contact)
        }
    }

    func didEnd(_ contact: SKPhysicsContact) {
        physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
        let (_, _, enders) = physicsContatctDelegates[world]!
        for each in enders.values {
            each.onNext(contact)
        }
    }

    let world: SKPhysicsWorld
}

private let physicsContatctDelegatesLock = NSRecursiveLock()
private var physicsContatctDelegates: [SKPhysicsWorld: (SKPhysicsContactDelegate, [UUID: AnyObserver<SKPhysicsContact>], [UUID: AnyObserver<SKPhysicsContact>])] = [:]