I am trying to perform segue to Home Screen after checking whether entered username and password are correct and if they are incorrect I am trying to show an alert message. I am not successful in performing either of those. Because as soon as I click the login button a white screen is displayed. Below is my code:
Performing segue in the following method:
@IBAction func didClickLogin(_ sender: Any) {
self.progressIndicator.isHidden = false
self.progressIndicator.startAnimating()
let enteredUserName = mMobileNumber.text
let enteredPassword = mPassword.text
//performing validation for username and password
didUserLogin(username: enteredUserName!, password: enteredPassword!)
return true
}
My didLogin function:
func didUserLogin(username: String, password: String) {
let requestString = Constants.BASE_URL+"/mlogin"
let parameters: Parameters = ["username":username, "password":password]
let headers = ["Authorization": "Basic \(Constants.base64LoginString)"]
Alamofire.request(requestString, method:.post, parameters: parameters, encoding: URLEncoding.default, headers: headers).responseJSON { response in
//to get status code
switch response.result {
case .success(let data):
let json = JSON(data)
switch (json["status"].stringValue){
case "200":
DispatchQueue.main.async {
self.performSegue(withIdentifier: "loginSuccess", sender: self)
}
break
case "401":
self.progressIndicator.isHidden = true
self.progressIndicator.stopAnimating()
let alert = Constants()
alert.showAlert(fromController: self, alertMessage: "Entered username or password is incorrect")
break
case .failure(let error):
print("Request failed with error: \(error)")
}
}
}
}
Please let me know what mistake am I doing and please let me know what changes do I need to do. I am not bale to display the alert message also. I am getting the below warning:
Warning: Attempt to present <UIAlertController: on whose view is not in the window hierarchy!
I think you just need to implement the following method, and it should work fine :
override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
if (segue.identifier == "YOUR_SCENE_IDENTIFIER_TO_THE_NEXT_SCREEN") {
// pass some data to the destination vc, if you need
}
}
执行序列的代码:
performSegue(withIdentifier: "loginSuccess", sender: nil)
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