Question

我遇到了一个奇怪的错误，我的函数在返回后将数值附加到数组中......代码如下：

func makeUser(first: String, last: String, email: String) -> [User] {

    var userReturn = [User]()

    RESTEngine.sharedEngine.registerUser(email, firstName: first, lastName: last, age: 12, success: { response in
        if let response = response, result = response["resource"], id = result[0]["_id"] {

            let params: JSON =
            ["name": "\(first) \(last)",
             "id": id as! String,
             "email": email,
             "rating": 0.0,
             "nuMatches": 0,
             "nuItemsSold": 0,
             "nuItemsBought": 0]
             let user = User(json: params)

            userReturn.append(user)
            print("\(userReturn)")

        }
        }, failure: { error in
            print ("Error creating a user on the server: \(error)")
    })

    return userReturn
}

我从这里打电话给make用户：

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    var newUser = makeUser("Average", last: "Person", email: "a.Person@mail.com")
    print("\(newUser)")
}

（这仍然是测试，所以我显然在奇怪的地方调用我的代码。）

因此，当我运行这个最终发生的事情时，首先是我的＆＃34; newUser＆＃34;数组被打印（它显示为空），然后我在makeUser函数中本地分配的userReturn数组打印，它包含我在＆＃34;成功＆＃34;中添加的新用户。完成块＆＃34; registerUser＆＃34;，如下：

有谁知道这里发生了什么，以及我如何解决它？

供参考：JSON只是我为[String：AnyObject]字典定义的类型。

Answer 1

registerUser以异步方式运行，因此您应该应用异步模式，例如完成处理程序：

func makeUser(first: String, last: String, email: String, completionHandler: ([User]?, ErrorType?) -> ()) {
    RESTEngine.sharedEngine.registerUser(email, firstName: first, lastName: last, age: 12, success: { response in
        if let response = response, result = response["resource"], id = result[0]["_id"] {
            var users = [User]()

            let params: JSON =
            ["name": "\(first) \(last)",
             "id": id as! String,
             "email": email,
             "rating": 0.0,
             "nuMatches": 0,
             "nuItemsSold": 0,
             "nuItemsBought": 0]
            let user = User(json: params)
            users.append(user)

            completionHandler(users, nil)
        } else {
            let jsonError = ...  // build your own ErrorType or NSError indicating that the the parsing of the JSON failed for some reason
            completionHandler(nil, jsonError)
        }
    }, failure: { error in
        completionHandler(nil, error)
    })
}

并像这样使用它：

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    makeUser("Average", last: "Person", email: "a.Person@mail.com") { users, error in
        guard error == nil else {
            print(error)
            return
        }

        print("\(users)")
        // if you're doing anything with this, use it here, e.g. reloadTable or update UI controls
    }

    // but don't try to use `users` here, as the above runs asynchronously
}

函数在返回Swift后赋值

1 个答案: