我如何从AlamoFire返回一些东西？

Question

import Foundation
import Alamofire
import UIKit
import SwiftyJSON

class APIClient: UIViewController {

    let loggedIn = false
    struct Constants{
        static let Domain = "http://gogogo.com"
    }

    func authenticate() -> Bool{
        println("Authenticating")
        if let access_token = FBSDKAccessToken.currentAccessToken().tokenString {
            let parameters = [ "access_token": access_token ]
            Alamofire.request(.POST, Constants.Domain+"/accounts", parameters: parameters).responseJSON {
            (req, res, json, error) in
                if(error != nil) {
                    self.sendReturnToSplash()
                } else {
                    let json = JSON(json!)
                    println("\(json)")
                    return true //This doesn't work!!!!!!
                }
            }
        }else{
            println("No access token to authenticate")
        }
    }

    func sendReturnToSplash(){
        let center = NSNotificationCenter.defaultCenter()
        let notification = NSNotification(name: NotificationCenters.ReturnToSplash, object: self, userInfo: ["":""])
        center.postNotification(notification)
    }
}

如您所见，如果注销成功，我想返回“true”。但是，XCode给了我一个“Void不符合协议BooleanLiteral”

Answer 1

由于您使用的是异步调用，因此应将authenticate函数视为异步。我建议使用类似于以下内容的完成块：

func authenticate(completion:(success: Bool) -> Void) {
    println("Authenticating")
    if let access_token = FBSDKAccessToken.currentAccessToken().tokenString {
        let parameters = [ "access_token": access_token ]
       Alamofire.request(.POST, Constants.Domain+"/accounts", parameters: parameters).responseJSON { (req, res, json, error) in
           if error != nil {
                self.sendReturnToSplash()
                completion(success: false)
            } else {
                let json = JSON(json!)
                println("\(json)")
                completion(success: true)
            }
        }
    } else {
        println("No access token to authenticate")
        completion(success: false)
    }
}