Error UIAlert when trying to do unwindsegue - ios

Question

I have a UIView which allow user to save some data with their desirable name before it can be view in the tableView
func saveFilesName() {
let alert = UIAlertController(title: "Save As", message: "Please enter the file name", preferredStyle: .alert)
alert.addTextField(configurationHandler: {(nameField) -> Void in
nameField.placeholder = "Enter the file name"
nameField.textAlignment = .center
})
alert.addTextField(configurationHandler: {(descField) -> Void in
descField.placeholder = "Enter the your description"
descField.textAlignment = .center
})
alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: { (actions: UIAlertAction) -> Void in
}))
alert.addAction(UIAlertAction(title: "Save", style: .default, handler: { (actions: UIAlertAction) -> Void in
let nameFieldData = alert.textFields![0]
let descFieldData = alert.textFields![1]
self.fileName = nameFieldData.text!
self.descData = descFieldData.text!
print(alert.textFields![0])
let saveCSV = self.saveCSVFiles()
print(saveCSV.lastPathComponent)
}))
self.present(alert, animated: true, completion: nil)
}
the problems is when I ran the code above, it will come with this error: "while an existing transition or presentation is occurring; the navigation stack will not be updated." right before the alert will normally pop up then it crash and the alert doesn't work.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
super.prepare(for: segue, sender: sender)
guard let button = sender as? UIBarButtonItem, button === saveButton else {
os_log("The save button was not pressed, cancelling", log: OSLog.default, type: .debug)
return
}
saveFilesName()
if fileName != nil {
let nsurl = String(describing: csvFile)
let name = fileName
let description = descData
let photo = UIImage(contentsOfFile: "defaultImage")
let url = NSURL(fileURLWithPath: nsurl)
csv = CSVData(name: name!, description: description!, photo: photo, url: url)
}
}
since the alert is needed before I can append any data to the class model. Any help would be appreciated

Answer 1

You don't need another IBAction, you can benefit from the user tapping on the Save button. Right?
inside your Save's handler ie here:
alert.addAction(UIAlertAction(title: "Save", style: .default, handler: { (actions: UIAlertAction) -> Void in
let nameFieldData = alert.textFields![0]
let descFieldData = alert.textFields![1]
self.fileName = nameFieldData.text!
self.descData = descFieldData.text!
print(alert.textFields![0])
let saveCSV = self.saveCSVFiles()
print(saveCSV.lastPathComponent)
}))
add the performSegue(withIdentifier: "YOUR_SEGUE_IDENTIFIER", sender: self) right after print(saveCSV.lastPathComponent)
so once you click save, it will dismiss the alert and then perform that segue.
This would trigger your prepare(for segue...)