Swift login screen performing segue - json

Question

I am using following code to login users first user enters password and id then using post request I am sending this information to the server.
let alert = UIAlertController(title: nil, message: "Please wait...", preferredStyle: .alert)
let message2 = "Please wait..."
var messageMutableString = NSMutableAttributedString()
messageMutableString = NSMutableAttributedString(string: message2 as String, attributes: [NSFontAttributeName:UIFont(name: "HelveticaNeue-Bold",size: 15.0)!])
alert.setValue(messageMutableString, forKey: "attributedMessage")
let loadingIndicator = UIActivityIndicatorView(frame: CGRect(x: 10, y: 5, width: 50, height: 50))
loadingIndicator.hidesWhenStopped = true
loadingIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.gray
loadingIndicator.startAnimating();
alert.view.addSubview(loadingIndicator)
present(alert, animated: true, completion: nil)
if Reachability.isConnectedToNetwork() == true {
var postString = GlobalVariable.globalIpAdress
postString.append("&userid=")
postString.append(userId.text!)
postString.append("&password=")
postString.append(password.text!)
postString.append("&parola=")
let urlString = postString.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlFragmentAllowed)
var request = URLRequest(url: URL(string:urlString!)!)
request.httpMethod = "POST"
request.timeoutInterval=10
message="Request timed out"
let task = URLSession.shared.dataTask(with: request) { data, response, error in
DispatchQueue.main.async {
self.dismiss(animated: false, completion: nil)
}
guard let data = data, error == nil else {
print("error=\(String(describing: error))")
DispatchQueue.main.async {
let alert = UIAlertView(title: "Uyarı!", message: self.message, delegate: nil, cancelButtonTitle: "OK")
alert.show()
}
return;
}
if let json = (try? JSONSerialization.jsonObject(with: data, options: [])) as? NSDictionary
{
print(json)
if (json["error"] as? String) != nil {}
if let messages = json["messages"] as? NSArray{
for item in messages {
if let description = item as? AnyObject {
if let text = description["text"] as? String {
self.message = text
}
}
}
}
if let tokenTemp = json["token"] as? String {
self.success=true
GlobalVariable.globalToken = tokenTemp
}
}
if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 {
print("statusCode should be 200, but is \(httpStatus.statusCode)")
print("response = \(String(describing: response))")
}
let responseString = String(data: data, encoding: .utf8)
print("responseString = \(String(describing: responseString))")
DispatchQueue.main.async {
if(self.success == true){
self.performSegue(withIdentifier: "secondVC", sender: self)
} else {
let alert = UIAlertView(title: "Warning!", message: self.message, delegate: nil, cancelButtonTitle: "OK")
alert.show()
}
}
}
task.resume()
}
else{
print("Internet connection FAILED")
let alert = UIAlertView(title: "No Internet Connection", message: "Make sure your device is connected to the internet.", delegate: nil, cancelButtonTitle: "OK")
alert.show()
}
First of all, I am adding indicator view for login screen and then, as soon as token came my Bool success variable is becoming true and I am dismissing the activity indicator then it needs to be gone next screen but it is not working right now and also I am getting following error.
Warning: Attempt to present UITabBarController on UIAlertController: whose view is not in the window hierarchy!
What could be the reason where am I doing wrong?

Answer 1

I think the error itself explains the issue here:
Attempt to present UITabBarController on UIAlertController: whose view is not in the window hierarchy!
As you are presenting the UIAlertController in this line of code :
present(alert, animated: true, completion: nil)
but you are not dismissing it and trying to performSegue on UIAlertController:
self.performSegue(withIdentifier: "secondVC", sender: self)
Dismiss the UIAlertController whenever you present it.
Refer this :
How to programmatically dismiss UIAlertController without any buttons?