如何在Swift 3中编写完成处理程序? [英] How do you write a completion handler in Swift 3?

问题描述

我想知道如何为在Swift 3中创建的函数创建完成处理程序. 这就是我在更新到Swift 3之前就完成功能的方式.

I was wondering how to make a completion handler for a function I'm creating in Swift 3. This is how I did my function right before I updated to Swift 3:

func Logout(completionHandler: (success: Bool) -> ()) {
    backendless.userService.logout(
        { ( user : AnyObject!) -> () in
            print("User logged out.")
            completionHandler(success: true)
        },
        error: { ( fault : Fault!) -> () in
            print("Server reported an error: \(fault)")
            completionHandler(success: false)
    })}

但是现在我无法找出目前可行的最佳方法.

But now I can't figure out the best approach that works right now.

推荐答案

在Swift 3中，闭包中的函数参数标签不见了.

In Swift 3 the function parameter labels in closures are gone.

删除所有出现的success:并添加@escaping

Remove all occurrences of success: and add @escaping

func Logout(completionHandler:@escaping (Bool) -> ()) {
    backendless?.userService.logout(
        { user in
            print("User logged out.")
            completionHandler(true)
        },
        error: { fault in
            print("Server reported an error: \(fault)")
            completionHandler(false)
    })
}

并使用它

Logout() { success in
   print(success)
}

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