ios - 使用 Swift 向 Google 应用引擎端点创建 REST 请求时出错

Question

我尝试使用 Swift for Google app engine 端点为我的对象发出请求，但出现错误，我已尝试更正它，但它不会通过。无论如何，我是 iOS 开发的新手。

import UIKit

class MainController: UITabBarController {
    var service : GTLRMyApiService?
    var myvalue: String?

    override func viewDidLoad() {

        if service == nil {
            service = GTLRMyApiService()
            service?.retryEnabled = true

        }

        let query : GTLRMyApiQuery_GetRates = GTLRMyApiQuery_GetRates.query()

        var ticket = GTLRServiceTicket.initialize
        ticket = service!.executeQuery(query, completionHandler: { (ticket: GTLRServiceTicket,  object: AnyObject!, error: NSError) -> Void in
            print("Analytics: \(object) or \(error)")
            let resp : GTLRMyApi_MyRates = object as! GTLRMyApi_MyRates
            print("Black Market Dollar rate is: \(resp.value1)")
            self.myvalue = resp.value1

    })

}

它给出了错误:

Cannot convert value of type '(GTLRServiceTicket, AnyObject!, NSError) -> Void' to expected argument type 'GTLRServiceCompletionHandler?'

Answer 1

我遇到了同样的问题并通过更改闭包中参数的展开解决了它:

ticket = service!.executeQuery(query, completionHandler: { (ticket: GTLRServiceTicket!,  object: AnyObject?, error: NSError?) -> Void in
        print("Analytics: \(object) or \(error)")
        let resp : GTLRMyApi_MyRates = object as! GTLRMyApi_MyRates
        print("Black Market Dollar rate is: \(resp.value1)")
        self.myvalue = resp.value1

})

我不是 Swift 专家，但我想这是为了匹配函数的 Objective-C 实现所期望的。 Xcode 没有说明这一点。