Change UILabel Text via UIAlertAction - swift

Question

I want to have an alert action change the text of a UILabel in my View. Code below:
#IBAction func statusChange(_ sender: UIButton){
let playalert = UIAlertController(title: "OPERATION: \(sender.accessibilityIdentifier!) NOT POSSIBLE", message: "Convert op to PLAY mode to proceed", preferredStyle: .alert)
let recordalert = UIAlertController(title: "OPERATION: \(sender.accessibilityIdentifier!) NOT POSSIBLE", message: "Convert op to STOP mode to proceed", preferredStyle: .alert)
let statechangealert = UIAlertController(title: "OPERATION: \(sender.accessibilityIdentifier!) WILL NOW PROCEED", message: "", preferredStyle: .alert)
let stopAction = UIAlertAction(title: "Convert", style: .default, handler: { action in
self.statusDVR.text = "STOP"//"\(sender.accessibilityIdentifier!)"
})
let continueAction = UIAlertAction(title: "Continue", style: .default, handler: { action in
self.statusDVR.text = ""//"\(sender.accessibilityIdentifier!)"
})
let returnAction = UIAlertAction(title: "Return", style: .default, handler: { action -> Void in
})
playalert.addAction(stopAction)
playalert.addAction(returnAction)
recordalert.addAction(stopAction)
recordalert.addAction(returnAction)
statechangealert.addAction(continueAction)
//record was tapped, check if DVR stopped first
if (sender.tag == 5 && pwrStat == true ) {
//if not stopped send alert
if statusDVR.text != "STOP" {
self.present(recordalert, animated:true, completion: nil)
//if user tapped returned action
if statusDVR.text != "STOP" {
self.present(statechangealert, animated:true, completion: nil)
} else {
return
}
} else {
statusDVR.text = "RECORD"
}
The stopAction should convert a UILAbel called statusDVR in the view controller, but it doesn't do it.
I haven't tried implementing the other Actions yet, because I am stuck trying to figure out why my UILabel's text won't change. Thank you for any help :)

Answer 1

First of all, this code makes no sense:
if statusDVR.text != "STOP" {
self.present(recordalert, animated:true, completion: nil)
if statusDVR.text != "STOP" {
self.present(statechangealert, animated:true, completion: nil)
That code tries to present two alerts at the same time. That is illegal.
I think you think that when you say
self.present(recordalert, animated:true, completion: nil)
...your code magically comes to a stop while the user interacts with the alert and then proceeds after the user dismisses the alert. That’s not the case. Your code never magically stops; it just keeps right on going.
As for the actual question you asked about, the problem is simply that what you're doing is illegal:
playalert.addAction(stopAction)
playalert.addAction(returnAction)
recordalert.addAction(stopAction)
recordalert.addAction(returnAction)
No! You cannot take one UIAlertAction and somehow magically "share" it between two different UIAlertControllers. Every UIAlertController needs UIActions that belong to it alone. In other words, do not call addAction on the same UIAlertAction twice.
Just to demonstrate more simply, try running this code:
let action1 = UIAlertAction(title: "Test", style: .default) {
_ in print("test")
}
let alert1 = UIAlertController(title: "Hello", message: nil, preferredStyle: .alert)
let alert2 = UIAlertController(title: "Hello2", message: nil, preferredStyle: .alert)
alert1.addAction(action1)
alert2.addAction(action1)
self.present(alert1, animated: true, completion: nil)
The alert appears, you tap the Test button, the alert disappears — but nothing prints in the console. Now comment out the next to last line:
// alert2.addAction(action1)
... and run the code again. This time, when you tap Test, "test" appears in the console.