Question

我是iOS的新手开发者，仍在向youtube学习或阅读有关swift等的电子书。

实际上我在youtube iOS Login and Signup Screen Tutorial上关注如何使用JSON数据创建iOS登录和注册的本教程，但我认为它在使用xcode 8的swift 3中运行良好的代码.I＆＃39一些问题/错误，我现在无法解决问题，我已经谷歌了，但我确实知道如何解决这个问题。

以下是我的LoginVC.swift文件中的屏幕截图

Screenshot of error on my LoginVC.swift

这里是LoginVC.swift中的所有代码

import UIKit

class LoginVC: UIViewController {

    @IBOutlet weak var txtUsername: UITextField!
    @IBOutlet weak var txtPassword: UITextField!


    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func btnLoginTapped(_ sender: UIButton) {
        // let userName = txtUsername.text;
        // let userPassword = txtPassword.text;

        let username = txtUsername.text
        let password = txtPassword.text

        if ( username!.isEqual("") || password!.isEqual("") ) {

            var alertView:UIAlertView = UIAlertView()
            alertView.title = "Sign in Failed!"
            alertView.message = "Please enter Username and Password"
            alertView.delegate = self
            alertView.addButton(withTitle: "OK")
            alertView.show()
        } else {

            var post:NSString = "username=\(username)&password=\(password)" as NSString

            NSLog("PostData: %@",post);

            var url:NSURL = NSURL(string:"http://192.168.1.17/userAPI/api/users")!

            var postData:NSData = post.data(using: String.Encoding.ascii.rawValue)! as NSData

            var postLength:NSString = String( postData.length ) as NSString

            var request:NSMutableURLRequest = NSMutableURLRequest(url: url as URL)
            request.httpMethod = "POST"
            request.httpBody = postData as Data
            request.setValue(postLength as String, forHTTPHeaderField: "Content-Length")
            request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
            request.setValue("application/json", forHTTPHeaderField: "Accept")


            var reponseError: NSError?
            var response: URLResponse?

            var urlData: NSData? = NSURLConnection.sendSynchronousRequest(request, returningResponse:&response, error: &reponseError)

            if ( urlData != nil ) {
                let res = response as! HTTPURLResponse!;
                // let dict: [String: Any] = ["key": value]
                NSLog("Response code: %ld", res?.statusCode ?? <#default value#>);

                if ((res?.statusCode)! >= 200 && (res?.statusCode)! < 300) {
                    var responseData:NSString  = NSString(data:urlData! as Data, encoding:String.Encoding.utf8.rawValue)!

                    NSLog("Response ==> %@", responseData);

                    var error: NSError?

                    let jsonData:NSDictionary = JSONSerialization.jsonObject(with: urlData!, options: JSONSerialization.ReadingOptions.mutableContainers, error: &error) as! NSDictionary

                    // let jsonData:NSDictionary = JSONSerialization.JSONObjectWithData(urlData!, options:JSONSerialization.ReadingOptions.MutableContainers , error: &error) as! NSDictionary

                    let success:NSInteger = jsonData.value(forKey: "success") as! NSInteger

                    //[jsonData[@"success"] integerValue];

                    NSLog("Success: %ld", success);

                    if(success == 1) {
                        NSLog("Login SUCCESS");

                        var prefs:UserDefaults = UserDefaults.standard
                        prefs.set(username, forKey: "USERNAME")
                        prefs.set(1, forKey: "ISLOGGEDIN")
                        prefs.synchronize()

                        self.dismiss(animated: true, completion: nil)
                    } else {
                        var error_msg:NSString

                        if jsonData["error_message"] as? NSString != nil {
                            error_msg = jsonData["error_message"] as! NSString
                        } else {
                            error_msg = "Unknown Error"
                        }
                        var alertView:UIAlertView = UIAlertView()
                        alertView.title = "Sign in Failed!"
                        alertView.message = error_msg as String
                        alertView.delegate = self
                        alertView.addButton(withTitle: "OK")
                        alertView.show()

                    }

                } else {
                    var alertView:UIAlertView = UIAlertView()
                    alertView.title = "Sign in Failed!"
                    alertView.message = "Connection Failed"
                    alertView.delegate = self
                    alertView.addButton(withTitle: "OK")
                    alertView.show()
                }
            } else {
                var alertView:UIAlertView = UIAlertView()
                alertView.title = "Sign in Failed!"
                alertView.message = "Connection Failure"
                if let error = reponseError {
                    alertView.message = (error.localizedDescription)
                }
                alertView.delegate = self
                alertView.addButton(withTitle: "OK")
                alertView.show()
            }
        }


    }

    func textFieldShouldReturn(textField: UITextField) -> Bool
    {   //delegate method
        textField.resignFirstResponder()
        return true
    }

}

错误实际上是在这些方面：

var urlData: NSData? = NSURLConnection.sendSynchronousRequest(request, returningResponse:&response, error: &reponseError)

NSLog("Response code: %ld", res?.statusCode ?? <#default value#>);

let jsonData:NSDictionary = JSONSerialization.jsonObject(with: urlData!, options: JSONSerialization.ReadingOptions.mutableContainers, error: &error) as! NSDictionary

我有点卡住并且混淆了如何解决这个问题。

这里有人帮忙解决这个问题吗？对此，我真的非常感激。或者可以有人告诉我如何在Swift3中使用API学习和创建登录屏幕？

感谢您帮助我，我希望您今天能够感受到一件好事！

Answer 1

这是因为获取数据时我们没有处理错误。因此，我们需要安全地键入种姓数据，然后将其传递给JsonSerializer。这是代码。

        do {
            let data = try NSData.init(contentsOfFile: path) as Data
            let jsonArray = try JSONSerialization.jsonObject(with: data, options: .mutableContainers)
            print(jsonArray)
        } catch {

        }

无法调用＆＃39; jsonObject＆＃39;使用类型＆＃39;的参数列表（with：NSData，options：JSONSerialization.ReadingOptions，error：inout NSError？）

1 个答案: