I have created a UIAlertController and added a text field into it. The problem is that the after I dismiss the alertcontroller, it is not deallocating and shows in the memory graph.
let alertController = UIAlertController(title: "Enter link", message: nil, preferredStyle: .alert)
alertController.addTextField { (textField) in
textField.placeholder = "www.xxx.com"
}
let cancel = UIAlertAction(title: "CANCEL", style: .cancel, handler: nil)
let ok = UIAlertAction(title: "SUBMIT", style: .default) { [weak self] (_) in
guard let self = self else { return }
guard let textFields = alertController.textFields, let textField = textFields.first else { return }
if let text = textField.text {
}
}
alertController.addAction(cancel)
alertController.addAction(ok)
present(alertController, animated: true, completion: nil)
However, if I remove the alertController.addTextField then it gets deallocated and it does not exist in the memory graph.
I tried checking if there are any memory leaks introduced due to my code but found none.
You're retaining the alertController inside of "ok" alert action, which is in turn retained by UIAlertController.
That's a retain cycle, neither of objects will be able to release each other.
You should avoid that, perhaps by using a weak reference, i.e:
let ok = UIAlertAction(title: "SUBMIT", style: .default) { [weak alertController] (_) in
// Upgrade weak to strong reference
guard let alertController = alertController else { return }
// Do your thing
}
Related
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 :)
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.
I'm trying to figure out how to keep the Action Button disabled until the user enters some text in, at which point the button would be enabled again. I've been searching around, and some people are suggesting to use Observers? Would that be the best way to go?
Cheers!
#objc func addExercise() {
var textField = UITextField()
let alert = UIAlertController(title: "New Exercise", message: "Please name your Exercise...", preferredStyle: .alert)
let cancelAction = UIAlertAction(title: "Cancel", style: .default) { (UIAlertAction) in
alert.dismiss(animated: true, completion: nil)
}
let addAction = UIAlertAction(title: "Add Exercise", style: .default) { (UIAlertAction) in
//Add Exercise to database.
//Append exercise to selected workout object.
let exercise = Exercises()
exercise.exerciseName = textField.text!
try! self.realm.write {
self.selectedWorkout?.exercise.append(exercise)
self.loadExercises()
}
}
alert.addTextField { (alertTextField1) in
alertTextField1.delegate = self
alertTextField1.placeholder = "Bench Press"
alertTextField1.text = textField.text
textField = alertTextField1
}
alert.addAction(addAction)
alert.addAction(cancelAction)
present(alert, animated: true, completion: nil)
}
Using notification is a way but long work instead you can use simple delegate method or action method of textfield which is much easier as follow:
weak var buttonActionToEnable: UIAlertAction?
alert.addTextField { (alertTextField1) in
alertTextField1.delegate = self
alertTextField1.placeholder = "Bench Press"
alertTextField1.text = textField.text
alertTextField1.addTarget(self, action: #selector(self.textFieldChanged), for: .editingChanged)
}
self.buttonActionToEnable = addAction
addAction.isEnabled = false
#objc func textFieldChanged(_ sender: Any) {
let textfield = sender as UITextField
self.buttonActionToEnable?.isEnabled = textfield.text.count > 0
}
i am working at my startscreen (viewDidAppear). At the beginning of the app, there should be an alert with some notice message. This works fine. After you click "ok" at the notice, the next alert should pop up with a text field. In this text field you have to type in a double value. I need this double value to set up a lot of things inside the app, so I need this value outside the function to calculate with it.
E.g. The notice message describes how the app works. You click OK. Now the next alert pop up with the text field. For example it asks your height. After you type in your height and click OK the height-value is the main part of different calculations.
The problem is now, that my app works with the nil-value before I typed in the double value (e.g. height)
These are the snippets from the code.
var iNeedTheDataHere:String?
///Alerts
//Start
let startController = UIAlertController(title: "Notice", message: "notice message ", preferredStyle: .alert)
let inputController = UIAlertController(title: "Set input", message: "Please set the input", preferredStyle: .alert)
//BeforeScreenLoad
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
// Start Alert
startController.addAction(UIAlertAction(title: "OK", style: .default, handler:{(action:UIAlertAction!) in
self.input()
}))
self.present(startController, animated: true)
}
func input() {
inputController.addTextField()
let submitAction = UIAlertAction(title: "Submit", style: .default) { [unowned ac] _ in
let answer = inputController.textFields![0].text
iNeedTheDataHere = answer
}
inputController.addAction(submitAction)
}
When I set Breakpoints, I see that the value of the inputController is set to nil, before I typed in anything. I guess my mistake has something to do with the handler
Sorry for my English
Hope somebody can help me
let alert = UIAlertController(title: "Alert!!!", message: "Please enter your message ", preferredStyle: .alert)
alert.addTextField(configurationHandler: self.configurationTextField)
alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler:{ (UIAlertAction) in
self.number.text?=""
MBProgressHUD.hide(for: self.view, animated: true)
}))
alert.addAction(UIAlertAction(title: "Done", style: .default, handler:{ (UIAlertAction) in
}))
self.present(alert, animated: true, completion: {
})
I have made some changes in your code to achieve that:
class ViewController: UIViewController {
let startController = UIAlertController(title: "Notice", message: "notice message ", preferredStyle: .alert)
let inputController = UIAlertController(title: "Set input", message: "Please set the input", preferredStyle: .alert)
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func viewDidAppear(_ animated: Bool) {
startController.addAction(UIAlertAction(title: "OK", style: .default, handler:{(action:UIAlertAction!) in
self.input()
}))
self.present(startController, animated: true)
}
func input() {
//Present another alert with textField
let confirmAction = UIAlertAction(title: "Submit", style: .default) { (_) in
guard let textFields = self.inputController.textFields,
textFields.count > 0 else {
// Could not find textfield
return
}
//get your textField
let answerTF = textFields[0]
let answer = answerTF.text
//Get values entered by user
print(answer)
}
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) { (_) in }
//add your textField here
inputController.addTextField { (textField) in
//Set a placeholde for textField
textField.placeholder = "Answer"
}
inputController.addAction(confirmAction)
inputController.addAction(cancelAction)
self.present(inputController, animated: true, completion: nil)
}
}
I have added comment to explain what I am doing.
And your result will be:
You can also check demo project here.
I have a button that if user click on it it must show another vc and it's working properly until I add UIAlertController which it's getting data from user and after user click done on alertaction nothing happens
this is my code:
#IBAction func DfsClicked(_ sender: AnyObject) {
let alertController = UIAlertController(title: "DFS?", message: "Please input DFS depth:", preferredStyle: .alert)
let confirmAction = UIAlertAction(title: "Confirm", style: .default) { (_) in
if let field = alertController.textFields?[0] {
// store your data
self.depth = Int(field.text!)!
print(self.depth)
Puzzle.AnswerNode = dfs(inputdepth: self.depth,SortedPuzzle:self.SortedPuzzle)
} else {
// user did not fill field
}
}
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) { (_) in }
alertController.addTextField { (textField) in
textField.placeholder = "Default is 2"
textField.keyboardType = UIKeyboardType.numberPad
}
alertController.addAction(confirmAction)
alertController.addAction(cancelAction)
self.present(alertController, animated: true)
}
Use this method to perform segue, inside confirm action block
self.performSegue(withIdentifier: <Identifier>, sender: <Any?>)
I've been looking up a lot of tutorials on UIAlertController. Thus far, the way I found was to activate a UIAlertController by linking it to a button or label and then call a IBAction.
I tried to replicate the code to automatically pop an alert when user enters the app (I wanted to ask the user if they want to go through the tutorial). However, I keep getting the error:
Warning: Attempt to present UIAlertController on MainViewController whose view is not in the window hierarchy!
Then I tried to add the UIAlertController to the MainViewController via addChildViewController and addSubview. However, I get the error:
Application tried to present modally an active controller
I figured that I cannot use the presentViewController function and commented it out.
The UIAlertController is displayed BUT when I tried to click on the cancel or the never button, this error occurs.
Trying to dismiss UIAlertController with unknown presenter.
I am really stumped. Can someone share what I am doing wrong? Thank you so much. Here is the code.
func displayTutorial() {
alertController = UIAlertController(title: NSLocalizedString("tutorialAlert", comment: ""), message: NSLocalizedString("tutorialMsg", comment: ""), preferredStyle: .ActionSheet)
self.addChildViewController(alertController)
self.view.addSubview(alertController.view)
alertController.didMoveToParentViewController(self)
alertController.view.frame.origin.x = self.view.frame.midX
alertController.view.frame.origin.y = self.view.frame.midY
//alertController.popoverPresentationController?.sourceView = self.view*/
let OkAction = UIAlertAction(title: NSLocalizedString("yesh", comment: ""), style: .Destructive) { (action) in
}
alertController.addAction(OkAction)
let cancelAction = UIAlertAction(title: NSLocalizedString("notNow", comment: ""), style: .Destructive) { (action) in
//println(action)
self.tutorial = 1
self.presentedViewController?.dismissViewControllerAnimated(true, completion: nil)
}
alertController.addAction(cancelAction)
let neverAction = UIAlertAction(title: NSLocalizedString("never", comment: ""), style: .Cancel) { (action) in
self.tutorial = 1
}
alertController.addAction(neverAction)
//self.presentViewController(alertController, animated: false) {}
}
I found the solution. Apparently, I cannot call the UIAlertController from the func viewDidLoad. I must call the function from viewDidAppear. So my code now is
override func viewDidAppear(animated: Bool) {
if tutorial == 0 {
displayTutorial(self.view)
}
}
func displayTutorial(sender:AnyObject) {
let alertController = UIAlertController(title: NSLocalizedString("tutorialAlert", comment: ""), message: NSLocalizedString("tutorialMsg", comment: ""), preferredStyle: .ActionSheet)
let OkAction = UIAlertAction(title: NSLocalizedString("yesh", comment: ""), style: .Destructive) { (action) in
}
alertController.addAction(OkAction)
let cancelAction = UIAlertAction(title: NSLocalizedString("notNow", comment: ""), style: .Default) { (action) in
//println(action)
self.tutorial = 1
self.presentedViewController?.dismissViewControllerAnimated(true, completion: nil)
}
alertController.addAction(cancelAction)
let neverAction = UIAlertAction(title: NSLocalizedString("never", comment: ""), style: .Cancel) { (action) in
self.tutorial = 1
}
alertController.addAction(neverAction)
self.presentViewController(alertController, animated: true, completion: nil)
if let pop = alertController.popoverPresentationController {
let v = sender as UIView
pop.sourceView = view
pop.sourceRect = v.bounds
}
}
Thanks to this posting: Warning: Attempt to present * on * whose view is not in the window hierarchy - swift
Below UIAlertController with extension would help you show alert with dynamic number of buttons with completion handler for selected index
extension UIViewController {
func displayAlertWith(message:String) {
displayAlertWith(message: message, buttons: ["Dismiss"]) { (index) in
}
}
func displayAlertWith(message:String, buttons:[String], completion:((_ index:Int) -> Void)!) -> Void {
displayAlertWithTitleFromVC(vc: self, title: Bundle.main.infoDictionary!["CFBundleDisplayName"] as! String, andMessage: message, buttons: buttons, completion: completion)
}
func displayAlertWithTitleFromVC(vc:UIViewController, title:String, andMessage message:String, buttons:[String], completion:((_ index:Int) -> Void)!) -> Void {
let alertController = UIAlertController(title: title, message: message, preferredStyle: .alert)
for index in 0..<buttons.count {
let action = UIAlertAction(title: buttons[index], style: .default, handler: {
(alert: UIAlertAction!) in
if(completion != nil){
completion(index)
}
})
alertController.addAction(action)
}
DispatchQueue.main.async {
vc.present(alertController, animated: true, completion: nil)
}
}
}
If you need to auto dismiss the alert you can call dismiss on presented view controller after some delay.
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 1) {
vc.dismiss(animated: true, completion: nil)
}
Hope this might help you.