在FSCalendar中使用RxSwift的DelegateProxy时出错

Question

RxFSCalendarDelegateProxy.swift

import Foundation
import RxSwift
import RxCocoa
import FSCalendar

class RxFSCalendarDelegateProxy: DelegateProxy<FSCalendar, FSCalendarDelegate>, DelegateProxyType, FSCalendarDelegate {
    static func registerKnownImplementations() {
        self.register { (calendar) -> RxFSCalendarDelegateProxy in
            RxFSCalendarDelegateProxy(parentObject: calendar, delegateProxy: self)
        }
    }
    
    static func currentDelegate(for object: FSCalendar) -> FSCalendarDelegate? {
        return object.delegate
    }
    
    static func setCurrentDelegate(_ delegate: FSCalendarDelegate?, to object: FSCalendar) {
        object.delegate = delegate
    }
}

extension Reactive where Base: FSCalendar {
    var delegate : DelegateProxy<FSCalendar, FSCalendarDelegate> {
        return RxFSCalendarDelegateProxy.proxy(for: self.base)
    }
    
    var didSelect : Observable<Date> {
        return delegate.methodInvoked(#selector(FSCalendarDelegate.calendar(_:didSelect:at:)))
            .map({ (params) in
                return params[1] as? Date ?? Date()
            })
    }
}

MainViewController.swift

import UIKit
import ReactorKit
import FSCalendar

class MainViewController: BaseViewController, View {
    
    typealias Reactor = MainViewReactor
    
    let calendar = FSCalendar()
    let label = UILabel()
    
    init(reactor: Reactor) {
        super.init()
        defer { self.reactor = reactor }
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    override func setupLayout() {
        self.view.addSubview(calendar)
    }
    
    override func makeConstraints() {
        
        self.calendar.snp.makeConstraints {
            $0.bottom.equalToSuperview()
            $0.top.equalToSuperview()
            $0.left.equalToSuperview()
            $0.right.equalToSuperview()
        }
    }
    
    func bind(reactor: MainViewReactor) {
        // MARK: input
        calendar.rx.didSelect.asObservable()
            .map { Reactor.Action.setDay($0) }
            .bind(to: reactor.action)
            .disposed(by: disposeBag)
        // MARK: output
    }

}

为了使用ReactorKit，我正在尝试将FSCalendarDelegate函数更改为Observable。但是当我运行这段代码时，出现了错误"RxCocoa/DelegateProxy.swift:230: Fatal error: Unexpectedly nil When implicitly an Optional value“我不知道如何修复我的DelegateProxy。为什么aSelector是nil？

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Answer 1

您发现了一个错误。由于FSCalendar询问委托是否响应选择器，但选择器为nil，因此代码崩溃。FSCalendar和RxCocoa都没有检查选择器中是否有nil。

I have submitted a pull request to the RxSwift repository to correct this problem.

在等待拉取请求通过系统时，您可以子类DelegateProxy并覆盖违规方法：

class MyDelegateProxy<P: AnyObject, D>: DelegateProxy<P, D> {
    override open func responds(to aSelector: Selector!) -> Bool {
        guard aSelector != nil else { return false }
        return super.responds(to: aSelector)
    }
}

class RxFSCalendarDelegateProxy: MyDelegateProxy<FSCalendar, FSCalendarDelegate>, DelegateProxyType, FSCalendarDelegate {
    static func registerKnownImplementations() {
        self.register { (calendar) -> RxFSCalendarDelegateProxy in
            RxFSCalendarDelegateProxy(parentObject: calendar, delegateProxy: self)
        }
    }

    static func currentDelegate(for object: FSCalendar) -> FSCalendarDelegate? {
        return object.delegate
    }

    static func setCurrentDelegate(_ delegate: FSCalendarDelegate?, to object: FSCalendar) {
        object.delegate = delegate
    }
}

至于为什么aSelector为零...当FSCalendar想要使用委托方法时，它首先检查该方法是否已经实现。如果不是，则检查是否实现了该方法的弃用版本。如果没有弃用的版本，那么它将询问委托是否实现了nil方法。我觉得FSCalender这样做有点傻，但很明显，如果这是在传统的委托实现上完成的，操作系统会返回false。RxCocoa只是假设没有任何库可以做到这一点。