无法在具有@objc 属性的协议中使用自定义类? [英] Unable to use custom class in a protocol with @objc attribute?

问题描述

我正在尝试为 JSON 加载委托创建一个协议，JSONLoaderDelegate.我的另一个类，称为 JSONLoader，应该将事件分派给它的委托(实现 JSONLoaderDelegate 协议)，例如:

I am trying to create a protocol for JSON loading delegation, JSONLoaderDelegate. My other class, called JSONLoader, is supposed to dispatch events to its delegate (that implements the JSONLoaderDelegate protocol) like:

self?.delegate?.jsonLoaderdidEndWithError(self!, error: JSONLoaderError.LoadError)

JSONLoader 的实现并不那么重要(恕我直言).但是我似乎在实现协议时遇到了问题，这是代码:

The implementation of the JSONLoader is not that important (imho). However I seem to have problems to implement the protocol, this is the code:

@objc protocol JSONLoaderDelegate {

    optional func jsonLoaderdidBeginLoading(jsonLoader: JSONLoader)
    func jsonLoaderdidEndWithError(jsonLoader: JSONLoader, error: JSONLoader.JSONLoaderError)
    func jsonLoaderDidEndWithSuccess(jsonLoader: JSONLoader)

}

这对我来说看起来很简单，但我收到一个错误:

This looks pretty straightforward to me but I am getting an error:

方法不能被标记为@objc，因为参数的类型不能用 Objective-C 表示.

method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C.

指向所有三个函数.

显然，如果我删除了 @objc 属性，我就不能将 optional 用于该函数.我真的很想将 jsonLoaderdidBeginLoading 保留为可选.有什么想法/方法可以解决这个问题吗?谢谢！

Obviously, if I remove the @objc attribute I cannot use the optional for the function. I would really like to keep jsonLoaderdidBeginLoading as optional tho. Any ideas / ways to solve this? Thank you!

推荐答案

这 3 种方法的共同点是 JSONLoader 参数，我认为这就是阻止您桥接协议的原因.为了解决这个问题，你必须让它兼容 objc.

What the 3 methods have in common is the JSONLoader parameter, and that's what I think prevents you from bridging the protocol. In order to solve the problem you have to make it objc compatible.

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