从视图控制器的分离文件中呈现视图控制器

Question

我有这个应用程序，它利用 Alamofire 将请求发送到后端，后端会吐出响应，并根据响应执行操作。我发现 Alamofire 代码对于我的项目来说太混乱了，我想将代码解析为一行代码。为此，我将 Alamofire 代码块放在我的一个自定义框架库中名为 Requests 的 class 中。每次我从后端收到响应时，我都想运行一个函数（不是问题），然后对下一个视图控制器（问题）执行 segue/present/push。

假设我有一个请求 class，其中包含一个接受用户名和密码参数的 login() 函数。调用此函数时的一行代码如下所示：Request.login(username, password)，最后是 Request.logout()，等等。可以在同一 Xcode 项目中的 ACommonLibrary 框架中找到此函数。这将运行 Alamofire 代码发送请求，然后以 JSON 格式获得“已验证：true”的响应，根据该应用程序将 segue/present /push 到配置文件视图控制器.

我试着用一个布尔值来做这件事，如果我得到一个响应，一个变量将从 false 设置为 true 并由函数返回，这样我就可以在 if/else 语句中使用它，但是那没有'不工作。我用

正常试过

let storyboard:UIStoryboard = UIStoryboard(name: "login", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "Login") as! LoginViewController
self.present(vc, animated: true, completion: nil)

但我得到实例成员‘present’不能用于类型'Request' 然后我发现有人问但那也没用，假设是因为我在一个故事板中有多个视图控制器。

我搜索了此错误和其他类似错误，但均无果。所以现在我在质疑这是否有可能实现，或者我是否必须以不同的方式处理它？任何建议都非常感谢。提前致谢。

编辑：在下面添加了代码。

主要
-> 登录
-> -> LoginViewController.swift

class LoginViewController: UIViewController {

    @IBOutlet weak var usernameTextField: CustomTextField!
    @IBOutlet weak var passwordTextField: CustomTextField!
    @IBOutlet weak var loginButton: UIButton!
    @IBOutlet weak var forgotPasswordButton: UIButton!
    @IBOutlet weak var navigationBar: UINavigationBar!

    override func viewWillAppear(_ animated: Bool) {
        UIApplication.shared.statusBarStyle = .lightContent
    }

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    // MARK: - IBActions
    @IBAction func loginPressed(sender: AnyObject) {
        usernameTextField.trimSpaces()

        let username = usernameTextField.text!
        let password = passwordTextField.text!

        Request.login(username, password)
    }
}

ACommonLibrary
-> 后端
-> -> Request.swift

public class Request {
    public class func login(_ username:String, _ password:String) {

    let headers: HTTPHeaders = [
        "Content-Type": "application/x-www-form-urlencoded"
    ]

    let parameters:Parameters = [
        "username": username,
        "password": password
    ]

    let endpoint = GlobalVariables.BaseURLString + "login"

    Alamofire.request(endpoint, method: .post, parameters: parameters, headers: headers)
    .responseJSON { response in
        switch response.result {
            case .success/*(let data)*/:
            if response.result.value != nil{
                let swiftyJsonVar = JSON(response.result.value!)

                let responseSuccess = swiftyJsonVar["success"]
                let responseMessage = swiftyJsonVar["error_message"]
                let responseSession = swiftyJsonVar["session_id"]
                let responseUserId = swiftyJsonVar["user_id"]

            if responseSession != JSON.null {
                GlobalVariables.Keychain["user_id"] = responseUserId.rawValue as? String
                GlobalVariables.Keychain["session_id"] =  responseSession.rawValue as? String
                try? GlobalVariables.Keychain.set(username, key: "username")

                if responseSuccess.boolValue {
                    let storyboard:UIStoryboard = UIStoryboard(name: "profile", bundle: nil)
                    let vc = storyboard.instantiateViewController(withIdentifier: "ProfileNavigation") as!     ProfileViewController
                    self.present(vc, animated: true, completion: nil)
                }else{
                    SCLAlertView().showNotice("Warning!", subTitle: responseMessage.stringValue)
                }
            }else{
                SCLAlertView().showError("Error logging in", subTitle: "There was an error while logging in     to your account. If this error persists, the server is down :D ")
            }
        }
        case .failure/*(let err)*/:
//          NSLog("------------------DATA START-------------------")
//          NSLog("Response String: (String(describing: err))")
            SCLAlertView().showError("Error logging in", subTitle: "There was an error while logging in to     your account. If this error persists, the server is down :D ")
//          NSLog("------------------DATA END-------------------")
        }
    }
}

Answer 1

首先你应该知道 self 在 class 方法中不可访问，而你试图在 Requests login 方法中执行 class .您尝试做的事情有两种可能，如下所述。

Requests 不是 UIViewController 的子 class。只有 UIViewController 或其子 class 可以呈现另一个视图控制器。因此可以利用共享应用程序的 keyWindow 和 rootViewController。方法如下：

if responseSuccess.boolValue {
    let storyboard:UIStoryboard = UIStoryboard(name: "profile", bundle: nil)
    let vc = storyboard.instantiateViewController(withIdentifier: "ProfileNavigation") as! ProfileViewController
    let rootVC = UIApplication.shared.keyWindow?.rootViewController
    rootVC?.present(vc, animated: true, completion: nil)
} else {
    SCLAlertView().showNotice("Warning!", subTitle: responseMessage.stringValue)
}

在进行异步网络调用的方法中使用闭包，就像您在 login 方法中所做的那样。然后在闭包中执行 segues 和 show/present 视图控制器。方法如下：

public class Request {
public class func login(_ username:String, _ password:String, withSuccess successHandler:@escaping (Bool) -> Void, andFailure failureHandler:@escaping (String) -> Void) {

    let headers: HTTPHeaders = ["Content-Type": "application/x-www-form-urlencoded"]

    let parameters:Parameters = ["username": username, "password": password]

    let endpoint = GlobalVariables.BaseURLString + "login"

    Alamofire.request(endpoint, method: .post, parameters: parameters, headers: headers)
        .responseJSON { response in
            switch response.result {
            case .success/*(let data)*/:
                if response.result.value != nil{
                    let swiftyJsonVar = JSON(response.result.value!)

                    let responseSuccess = swiftyJsonVar["success"]
                    let responseMessage = swiftyJsonVar["error_message"]
                    let responseSession = swiftyJsonVar["session_id"]
                    let responseUserId = swiftyJsonVar["user_id"]

                    if responseSession != JSON.null {
                        GlobalVariables.Keychain["user_id"] = responseUserId.rawValue as? String
                        GlobalVariables.Keychain["session_id"] =  responseSession.rawValue as? String
                        try? GlobalVariables.Keychain.set(username, key: "username")

                        if responseSuccess.boolValue {
                            successHandler(true)
                        } else {
                            failureHandler(responseMessage.stringValue)
                        }
                    } else {
                        failureHandler("There was an error while logging in to your account. If this error persists, the server is down :D")
                    }
                }
            case .failure/*(let err)*/:
                failureHandler("There was an error while logging in to your account. If this error persists, the server is down :D")
            }
        }
    }
}

然后在LoginViewController

@IBAction func loginPressed(sender: AnyObject) {
    usernameTextField.trimSpaces()

    let username = usernameTextField.text!
    let password = passwordTextField.text!

    Request.login(username,
                  password,
                  withSuccess: { (success) in
                    let vc = self.storyboard?.instantiateViewController(withIdentifier: "ProfileViewController") as! ProfileViewController
                    self.present(vc, animated: true, completion: nil)
    }) { (errorMsg) in
        SCLAlertView().showError("Error logging in", subTitle: errorMsg)
    }
}

从视图控制器的分离文件中呈现视图控制器

Present a view controller from a detached file from view controller

ios

swift

segue

alamofire

uistoryboard