Swift 声明 AnyClass 对象实现协议 [英] Swift declare that AnyClass object implements protocol

问题描述

我目前正在编写一个框架，用于为我的 OS X 应用程序创建插件.这些插件作为 NSBundle 加载，并且包的 principalClass 用于运行插件代码.但是，我不知道如何声明 principalClass 对象符合我的协议.

I am currently writing a framework for creating plugins for my OS X application. These plugins are loaded as NSBundles, and the bundles' principalClasses are used to run the plugin code. However, I can't figure out how to declare that the principalClass object conforms to my protocol.

let bundles = CFBundleCreateBundlesFromDirectory(kCFAllocatorDefault, NSURL(fileURLWithPath: bundleDirectory), "bundle") as NSArray

for bundle in bundles
{
    let bundleClass = bundle.principalClass!!

    if (bundleClass.conformsToProtocol(MyProtocol.self))
    {
        //Produces compiler error:
        //"Cannot downcast from 'AnyClass' to non-@objc protocol type 'MyProtocol'"
        let loadedClass = bundleClass as MyProtocol
    }
}

声明它符合这个协议的正确语法是什么?(另外，这个协议被声明为 @objc 所以我不知道为什么它说非@objc"协议.)

What is the proper syntax for declaring that it conforms to this protocol? (Also, this protocol is declared @objc so I'm not sure why it says "non-@objc" protocol.)

推荐答案

尝试:bundleClass as MyProtocol.Protocol.文档 此处.

顺便说一句，你的代码可以简化

BTW, your code can be simplified

let bundles = CFBundleCreateBundlesFromDirectory(kCFAllocatorDefault, NSURL(fileURLWithPath: bundleDirectory), "bundle") as NSArray
for bundle in bundles {
    if let loadedClass = bundle.principalClass as? MyProtocol.Protocol {
        // ...
    }
}

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