Xcode 8 beta 6:main.swift 不会编译 [英] Xcode 8 beta 6: main.swift won't compile

问题描述

我们有一个自定义的 UIApplication 对象，所以我们的 main.swift 是

We have a custom UIApplication object, so our main.swift was

import Foundation
import UIKit

UIApplicationMain(Process.argc, Process.unsafeArgv, NSStringFromClass(MobileUIApplication), NSStringFromClass(AppDelegate))

这在 Xcode 8 beta 5 中不起作用，所以我们使用了这个

and that didn't work in Xcode 8 beta 5 so we used this

//TODO Swift 3 workaround? https://forums.developer.apple.com/thread/46405
UIApplicationMain( Process.argc, UnsafeMutablePointer<UnsafeMutablePointer<CChar>>(Process.unsafeArgv), nil, NSStringFromClass(AppDelegate.self))

在 Xcode 8 beta 6 上，我们得到 使用未解析的标识符进程"

On Xcode 8 beta 6 we get Use of unresolved identifier 'Process'

我们需要在 Xcode 8 beta 6/Swift 3 中做什么来定义 UIApplicationMain?

What do we need to do in Xcode 8 beta 6/Swift 3 to define the UIApplicationMain?

推荐答案

我是这样写的:

UIApplicationMain(
    CommandLine.argc,
    UnsafeMutableRawPointer(CommandLine.unsafeArgv)
        .bindMemory(
            to: UnsafeMutablePointer<Int8>.self,
            capacity: Int(CommandLine.argc)),
    nil,
    NSStringFromClass(AppDelegate.self)
)

要更改 UIApplication 类，请在该公式中将 NSStringFromClass(MobileUIApplication.self) 替换为 nil.

To change the UIApplication class, substitute NSStringFromClass(MobileUIApplication.self) for nil in that formulation.

但是，如果您在此处唯一的目的是将 UIApplication 子类替换为共享应用程序实例，则有一种更简单的方法:在 Info.plist 中，添加"Principal class" 键并将其值设置为您的 UIApplication 子类的字符串名称，并使用 @objc(...) 属性标记该子类的声明，并赋予它相同的 Objective-C 名称.

However, if your only purpose here is to substitute a UIApplication subclass as the shared application instance, there's an easier way: in the Info.plist, add the "Principal class" key and set its value to the string name of your UIApplication subclass, and mark your declaration of that subclass with an @objc(...) attribute giving it the same Objective-C name.

EDIT 这个问题现在在 Swift 4.2 中得到解决.CommandLine.unsafeArgv 现在有了正确的签名，并且可以轻松调用 UIApplicationMain:

EDIT This problem is now solved in Swift 4.2. CommandLine.unsafeArgv now has the correct signature, and one can call UIApplicationMain easily:

UIApplicationMain(
    CommandLine.argc, CommandLine.unsafeArgv, 
    nil, NSStringFromClass(AppDelegate.self)
)

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