Xcode 8 Beta 6:main.swift无法编译 [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))

并且在Xcode 8 beta 5中不起作用，因此我们使用了

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'Process'

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

我们需要在Xcode 8 beta 6/Swift 3中定义UIApplicationMain吗?

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

推荐答案

我这样写:

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，如果您的 only 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"主体类"键，并将其值设置为UIApplication子类的字符串名称，并使用@objc(...)属性为该子类的声明进行标记，并为其赋予相同的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.

编辑现在，此问题已在Swift 4.2中解决. CommandLine.unsafeArgv现在具有正确的签名，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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