Question

我将项目从swift 1升级到2，并且我试图解决所有已经出现的问题。

我仍然有一些离开，我正在努力绕开。

我有这种方法，正如你所看到的那样抛出错误。我知道它与do / try / catch有关，但是我无法让他们离开我的任何尝试。

struct EventDao {

    // MARK: Functions

    /**
        Get all the upcoming events
    */
    static func getUpcoming(callback: (NSArray?, String?) -> Void) {

        let request = NSMutableURLRequest(URL: NSURL(string: Constants.makeUrl("/events"))!)
        request.HTTPMethod = "GET"
        request.addValue("application/json", forHTTPHeaderField: "Content-Type")
        request.addValue("application/json", forHTTPHeaderField: "Accept")
        let token = NSUserDefaults.standardUserDefaults().stringForKey("myezteamToken")
        request.addValue("Bearer \(token!)", forHTTPHeaderField: "Authorization")


            let session = NSURLSession.sharedSession()
            let task = session.dataTaskWithRequest(request) {  <-- // INVALID CONVERSION FROM THROWING FUNCTION OF TYPE '(_, _, _) THROWS -> VOID' TO NON-THROWING FUNCITON '(NSDATA?, NSURLRESPONSE?, NSERROR?) -> VOID'
                (data, response, error) -> Void in

                if error != nil {
                    callback(nil, error.localizedDescription) <-- // TYPE OF EXPRESSION IS AMBIGUOUS WITHOUT MORE CONTEXT
                } else {
                    let newData: NSData = data
                    let upcomingEvents: NSArray = try NSJSONSerialization.JSONObjectWithData(newData, options: NSJSONReadingOptions.AllowFragments) as! NSArray
                    callback(upcomingEvents, nil)
                }
            }


        task.resume()

    }

}

Answer 1

首先，您需要打开error属性，如果它不是零。然后，您需要将您的JSON序列化代码包装在do / try / catch中。你得到的错误信息是红鲱鱼。一旦你在do / try / catch中包装JSON东西，它就会消失。当您将as?的结果转换为JSONObjectWithData时，您还需要使用NSArray。试试这个：

static func getUpcoming(callback: (NSArray?, String?) -> Void) {

    let request = NSMutableURLRequest(URL: NSURL(string: "bob")!)
    request.HTTPMethod = "GET"
    request.addValue("application/json", forHTTPHeaderField: "Content-Type")
    request.addValue("application/json", forHTTPHeaderField: "Accept")
    let token = NSUserDefaults.standardUserDefaults().stringForKey("myezteamToken")
    request.addValue("Bearer \(token!)", forHTTPHeaderField: "Authorization")


    let session = NSURLSession.sharedSession()
    let task = session.dataTaskWithRequest(request) { (data, response, error) -> Void in
        if error != nil {
            callback(nil, error!.localizedDescription)
        }
        else {
            let newData: NSData = data!
            let upcomingEvents: NSArray?
            do {
                upcomingEvents = try NSJSONSerialization.JSONObjectWithData(newData, 
                    options: NSJSONReadingOptions.AllowFragments) as? NSArray
            } catch {
                upcomingEvents = nil
            }
            callback(upcomingEvents, nil)
        }
    }

    task.resume()

}

升级到swift 2会导致我努力绕过的错误

1 个答案: