【发布时间】：2021-06-20 16:33:45
【问题描述】：
我是 swift 的初学者，我试图使用 UIAlertController 但我遇到了一个错误，UiAlertController 没有出现，我可以看到一个错误在控制台中显示
2021-06-20 18:16:28.494162+0200 Bicycall[50670:543648] [Presentation] Attempt to present <UIAlertController: 0x7fbaca034e00> on <Bicycall.login: 0x7fbabb01d800> (from <Bicycall.login: 0x7fbabb01d800>) whose view is not in the window hierarchy.
2021-06-20 18:16:28.494339+0200 Bicycall[50670:543648] [Presentation] Attempt to present <UIAlertController: 0x7fbac9862800> on <Bicycall.login: 0x7fbabb01d800> (from <Bicycall.login: 0x7fbabb01d800>) whose view is not in the window hierarchy.
这是我尝试过的：
import UIKit
import CoreData
import AVKit
import AVFoundation
import TKSubmitTransition
class login: UIViewController {
@IBOutlet weak var passwordView: UIView!
@IBOutlet weak var emailView: UIView!
var id: Int?
var name: String?
var lastname: String?
var email:String?
var password:String?
var phone:String?
var u = ConnectedUser()
var BR = BaseUrl.baseUrl
var player: AVPlayer?
let videoURL: NSURL = Bundle.main.url(forResource: "Bikers", withExtension: "mp4")! as NSURL
func getTopMostViewController() -> UIViewController? {
var topMostViewController = UIApplication.shared.keyWindow?.rootViewController
while let presentedViewController = topMostViewController?.presentedViewController {
topMostViewController = presentedViewController
}
return topMostViewController
}
func presentTestAlert(_ title: String, _ message: String){
let alert = UIAlertController(title: title , message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: NSLocalizedString("OK", comment: "Default action"), style: .default, handler: { _ in
NSLog("The \"OK\" alert occured.")
}))
DispatchQueue.main.async {
self.getTopMostViewController()?.present(alert, animated: true, completion: nil)
}
}
override func viewDidLoad() {
super.viewDidLoad()
self.DeleteAllData()
player = AVPlayer(url: videoURL as URL)
player?.actionAtItemEnd = .none
player?.isMuted = true
let playerLayer = AVPlayerLayer(player: player)
playerLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
playerLayer.zPosition = -1
playerLayer.frame = view.frame
view.layer.addSublayer(playerLayer)
player?.play()
NotificationCenter.default.addObserver(forName: .AVPlayerItemDidPlayToEndTime, object: self.player?.currentItem, queue: .main) { [weak self] _ in
self?.player?.seek(to: CMTime.zero)
self?.player?.play()
// Do any additional setup after loading the view.
}
emailView.layer.cornerRadius = 30.0
emailView.layer.borderWidth = 0.5
emailView.layer.borderColor = UIColor.white.cgColor
passwordView.layer.cornerRadius = 30.0
passwordView.layer.borderWidth = 0.5
passwordView.layer.borderColor = UIColor.white.cgColor
}
//widgets
@IBOutlet weak var txtEmail: UITextField!
@IBOutlet weak var txtPassword: UITextField!
//Actions
@IBAction func btnLogin(_ sender: Any){
//get
/*
guard let url = URL(string: "http://localhost:3000/bikes") else {
return
}
let session = URLSession.shared
session.dataTask(with: url) { ( data , response ,error) in
if let response = response {
print(response)
}
if let data = data {
print(data)
do
{
let json = try JSONSerialization.jsonObject(with: data, options: [])
print(json)
}catch{
print(error)
}
}
}.resume()
*/
//post
guard let url = URL(string: BR+"/login") else {
return
}
let bodyparameters = ["email": txtEmail.text, "password": txtPassword.text]
if (txtEmail.text!.isEmpty || txtPassword.text!.isEmpty ){
self.presentTestAlert("Wrong credentials","Email and Password must not be empty")
}else{
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
guard let httpBody = try? JSONSerialization.data(withJSONObject: bodyparameters, options: []) else{
return
}
request.httpBody = httpBody
let session = URLSession.shared
session.dataTask(with: request) { (data,response,error) in
let status = (response as! HTTPURLResponse).statusCode
//print(response)
print(status)
if let response = response {
let status = (response as! HTTPURLResponse).statusCode
//print(response)
print(status)
}
if((status) == 200){
self.presentTestAlert("Connection Success", " internet connection")
print(" Connection Successssssssssssssss")
if let data = data {
do {
//let json = try JSONSerialization.jsonObject(with: data, options: [])
// print(json);
print(data)
let user = try JSONDecoder().decode(User.self, from: data)
DispatchQueue.main.async {
self.id = user.user_id
self.name = user.name
self.lastname = user.lastname
self.email = user.email
self.password = user.password
self.phone = user.phone
print(self.id!)
print(self.email!)
if(user.user_id != 0){
self.saveUser()
self.DisplayConnectedUser()
self.performSegue(withIdentifier: "HomeSegue", sender: "nil")
}else{
self.presentTestAlert("Login Failed","Wrong credentials")
}
}
}catch{
print(error)
}
}
}else {
self.presentTestAlert("No Connection", "No internet connection")
print(" Connection Nooooooooooooooooooooooooo")
}
}.resume()
}
}
func DeleteAllData(){
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.persistentContainer.viewContext
let DelAllReqVar = NSBatchDeleteRequest(fetchRequest: NSFetchRequest<NSFetchRequestResult>(entityName: "Users"))
do {
try managedContext.execute(DelAllReqVar)
}
catch {
print(error)
}
}
func saveUser() {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
//represente l'ORM
let persistentContainer = appDelegate.persistentContainer
let managedContext = persistentContainer.viewContext
let entityDescription = NSEntityDescription.entity(forEntityName: "Users" , in: managedContext)
let object = NSManagedObject(entity: entityDescription! , insertInto: managedContext )
object.setValue(id! , forKey: "user_id" )
object.setValue(email! , forKey: "email" )
object.setValue(password! , forKey: "password" )
object.setValue(name! , forKey: "name" )
object.setValue(lastname! , forKey: "lastname" )
object.setValue(phone! , forKey: "phone" )
do {
try managedContext.save()
print("INSERT SUCCESSFULLY")
print(id!)
}
catch {
print("INSERT ERROR")
}
}
@IBAction func btnSignup(_ sender: Any) {
performSegue(withIdentifier: "signupSegue", sender: "nil")
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
}
func DisplayConnectedUser() {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
//represente l'ORM
let persistentContainer = appDelegate.persistentContainer
let managedContext = persistentContainer.viewContext //retourne NSManagedObject toujours
//la requete retourne un NSManagedObject
let request = NSFetchRequest<NSManagedObject>(entityName : "Users")
//execution de la requete
do {
let result = try managedContext.fetch(request)
for item in result {
print(item.value(forKey: "user_id") as! Int )
print(item.value(forKey: "email") as! String)
self.u.user_id = (item.value(forKey: "user_id") as! Int)
self.u.email = (item.value(forKey: "email") as! String)
self.u.password = (item.value(forKey: "password") as! String)
self.u.name = (item.value(forKey: "name") as! String)
self.u.lastname = (item.value(forKey: "lastname") as! String)
self.u.phone = (item.value(forKey: "phone") as! String)
print(self.u.user_id!)
print(self.u.email!)
print(self.u.password!)
print(self.u.name!)
print(self.u.lastname!)
print(self.u.phone!)
}
}
catch {
print("NO DATA FOUND , Error")
}
}
}
让我烦恼的是，我的警报都不起作用！我在 stackoverflow 中阅读了其他一些答案，但这些解决方案对我不起作用
我正在尝试让我的警报正常工作
任何帮助将不胜感激
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