所以我最近开始将代码迁移到 MVVM 模式,但遇到了一些问题。 目前我正在开发对用户进行身份验证的登录页面。 问题是我调用我的函数,但我的代码不等待它的响应并移至下一行。我认为那是因为 Alamofire 的异步功能。 这是我的代码:
// My login view controller
class loginPageViewController: UIViewController, UITextFieldDelegate {
private var viewModel = userViewModel()
@IBOutlet weak var usernameTextField: UITextField!
@IBOutlet weak var passwordTextField: UITextField!
@IBAction func signInButton(_ sender: roundButton) {
if(usernameTextField.text != "" && passwordTextField.text != "") {
self.viewModel.validate(nameField: self.usernameTextField.text!, passField: self.passwordTextField.text!)
if(self.viewModel.isDone){
print("success")
self.presentPage(identifier: "homePageNavCtrl")
}
}
}
override func viewDidLoad() {
super.viewDidLoad()
usernameTextField.delegate = self
passwordTextField.delegate = self
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool{
usernameTextField.resignFirstResponder()
passwordTextField.resignFirstResponder()
return true;
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
self.view.endEditing(true)
}
}
private extension loginPageViewController{
func displayErrorMessage(errorMessage: String){
let alert = UIAlertController(title: "Error", message: errorMessage, preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
func presentPage(identifier: String){
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewController(withIdentifier: identifier)
self.present(nextViewController, animated:true, completion:nil)
}
}
我想要做的是,当点击登录按钮时,使用 JSON 请求验证用户,如果凭据正确,则转到下一页。
这是我的 userViewModel
class userViewModel{
private var mng = restInterface()
private var User = user()
var isDone = false
var id: Int {
return User.ID
}
var username: String {
return User.LOGINNAME
}
var password: String {
return User.PASSHASH
}
}
extension userViewModel{
func updateId(id: Int){
User.ID = id
}
func updateUsername(username: String){
User.LOGINNAME = username
}
func updatePassword(password: String){
User.PASSHASH = password
}
func validate(nameField: String, passField: String){
let accountBaseURL = "myUrlLiesDownHere"
var nm = nameField
var ps = passField
nm.insert("'", at: nm.startIndex)
nm.insert("'", at: nm.endIndex)
ps.insert("'", at: ps.startIndex)
ps.insert("'", at: ps.endIndex)
let params : [String: String] = ["sUser" : nm, "sPass" : ps, "sToken": "''"]
self.mng.performRequest(URLString: accountBaseURL, parameters: params, method: .get, successCallback: { (dict) in
self.User.ID = dict.value(forKey: "ID") as! Int
self.User.LOGINNAME = dict.value(forKey: "LOGINNAME") as! String
self.User.PASSHASH = dict.value(forKey: "PASSHASH") as! String
self.loginDone()
}) { (error) in
print("Error")
}
}
func loginDone(){
self.isDone = true
}
}
这是我的休息界面
class restInterface {
func performRequest(URLString: String, parameters : Parameters, method:HTTPMethod, successCallback: @escaping (NSDictionary) -> Void, errorCallBack: @escaping (String) -> Void) -> Void{
Alamofire.request(URLString, method: method, parameters: parameters).responseJSON { response in
print(response)
if let JSON = response.result.value as? [String: Any] {
print(JSON)
successCallback(JSON as NSDictionary)
} else {
errorCallBack("JSON Doesn't Exist")
}
}
}
}
当我在 View Controller 中控制 userViewModel 上的 isDone bool 值时,它必须为 true。但事实并非如此。当我按下按钮一次时,结果变为 true,但什么也没有发生。当我再次点击它时,它会将我重定向到我想要的下一页。 因此,使用异步确实让我很困惑,我正在这里寻求帮助:) 谢谢...
最佳答案
在您的UserViewModel
中,创建一个completionHandler
回调并在viewController
内部实现它以呈现下一个viewController
.
class UserViewModel {
public var loginCompletion: (()-> Void)?
private var mng = restInterface()
private var User = user()
// rest of your code
}
一旦请求完成,调用completionHandler
,
extension userViewModel{
func validate(nameField: String, passField: String){
let accountBaseURL = "myUrlLiesDownHere"
var nm = nameField
var ps = passField
nm.insert("'", at: nm.startIndex)
nm.insert("'", at: nm.endIndex)
ps.insert("'", at: ps.startIndex)
ps.insert("'", at: ps.endIndex)
let params : [String: String] = ["sUser" : nm, "sPass" : ps, "sToken": "''"]
self.mng.performRequest(URLString: accountBaseURL, parameters: params, method: .get, successCallback: { (dict) in
self.User.ID = dict.value(forKey: "ID") as! Int
self.User.LOGINNAME = dict.value(forKey: "LOGINNAME") as! String
self.User.PASSHASH = dict.value(forKey: "PASSHASH") as! String
self.loginDone()
self.loginCompletion?()
}) { (error) in
print("Error")
}
}
func loginDone(){
self.isDone = true
}
}
completionHandler
在 viewController
中的使用,
class loginPageViewController: UIViewController, UITextFieldDelegate {
private var viewModel = userViewModel()
@IBOutlet weak var usernameTextField: UITextField!
@IBOutlet weak var passwordTextField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
usernameTextField.delegate = self
passwordTextField.delegate = self
self.viewModel.loginCompletion = { [weak self] in
print("success")
self?.presentPage(identifier: "homePageNavCtrl")
}
}
@IBAction func signInButton(_ sender: roundButton) {
if(usernameTextField.text != "" && passwordTextField.text != "") {
self.viewModel.validate(nameField: self.usernameTextField.text!, passField: self.passwordTextField.text!)
}
}
// rest of your code
}
注意:在 Swift 中,class/struct/enum
名称应以 Capital 字母开头。上面的解决方案是观察 view-viewModel 之间数据的非常基本的设置。您应该寻找更好的数据绑定(bind)解决方案,例如 Rx-Swift , Bond , Two-Way Binding等等
关于ios - 如何在不破坏 MVVM 模式的情况下处理 Alamofire 的结果,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56882615/