I have a UIAlertController with a style of ActionSheet.
I've added a cancel action to it.
The thing is that for some reason when the user taps outside of the ActionSheet box - the alert is dismissed.
How can I disable this behavior? I want the user to press the cancel button directly.
swift 4 / Xcode 11
Hi. To disable user interaction (example: tapping anywhere but the cancel button), call the present method in your alert function and set it's completion closure as below code.
present(alertController, animated: true) {
alertController.view.superview?.subviews[0].isUserInteractionEnabled = false
}
The whole example:
func alertMe() {
let alertController = UIAlertController(title: "Tapping Test", message: "User Interaction on the view is disabled", preferredStyle: .actionSheet)
let cancelAction = UIAlertAction(title: "cancel", style: UIAlertActionStyle.cancel) { UIAlertAction in
// do something/call someone/or nothing :)
NSLog("cancel Button is Pressed")
}
alertController.addAction(cancelAction)
present(alertController, animated: true){
alertController.view.superview?.subviews[0].isUserInteractionEnabled = false
}
}
Related
I have implemented action sheet though alert controller. I want to display a button like cancel button with "Pay" Text written on it.
Issue is makeCall() function call when pay button is clicked , And when rest of the screen is tapped makeCall() function is called again.
How can I identify that action is called through pay button action or through Tapp on rest of the screen? I only want to make call to makeCall() function when pay button is tapped.
alertController = UIAlertController(title: "", message: nil, preferredStyle: .actionSheet)
let cancelAction = UIAlertAction(title: "Pay", style: .cancel) { (UIAlertAction) in
printLog("cancelAction")
makeCall()
}
cancelAction.isEnabled = false
alertController.addAction(cancelAction)
self.present(alertController, animated: true) {}
Here, alert controller view userInteraction disable so when tap outside alert controller not close.
You can do like this:
self.present(alertController, animated: true){
if let mainView = alertController.view.superview?.subviews[0]{
mainView.isUserInteractionEnabled = false
}
}
OR
self.present(alertController, animated: true) {
if let allContainerView = alertController.view.superview?.subviews{
for myview in allContainerView{
if (myview.gestureRecognizers != nil){
myview.isUserInteractionEnabled = false
}
}
}
}
I hope it will work for you.
I don't find any solution that how can you identify that action is called through pay button action or through Tap on rest of the screen.
but the alter solution is that you add tap gesture on rest view. So, you can identify that if cancel button tap or tap in rest of the screen.
alertController = UIAlertController(title: "", message: nil, preferredStyle: .actionSheet)
let cancelAction = UIAlertAction(title: "Pay", style: .cancel) { (UIAlertAction) in
printLog("cancelAction")
makeCall()
}
alertController.addAction(cancelAction)
self.present(alertController, animated: true) {
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(self.dismissAlertController))
alertController.view.superview?.subviews[0].addGestureRecognizer(tapGesture)
}
#objc func dismissAlertController(){
self.dismiss(animated: true, completion: nil)
print("through Tap on rest of the screen")
}
I am trying to make cancel button work and navigate to the previous screen. I am pressing outside the action sheet and the cancel event is still occurring.
Here is my code:
let alertController = UIAlertController(title: "searchEvent", message: nil, preferredStyle: .actionSheet)
alertController.addAction(UIAlertAction(title: "event 1", style: .default, handler: nil)
alertController.addAction(UIAlertAction(title: "event 2", style: .default, handler: nil)
alertController.addAction(UIAlertAction(title: "event 3", style: .default, handler: nil)
alertController.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: {[weak self] (action) in
self?.dismiss(animated: true, completion: nil)
}))
self.present(alertController, animated: true, completion: {
alertController.view.superview?.subviews[0].isUserInteractionEnabled = false
})
This will disable any behavior for user tapping outside the action sheet
If you want different behavior for tapping cancel and tapping outside of action sheet, former cancels and dismisses VC, later only cancels action sheet, then you need to change your cancel button style to something other than cancel and then add a gesture recognizer to
self.actionSheet.view.superview?.subviews.first?
The gesture recognizer block will dismiss the action sheet
The cancel button block will dismiss the view controller.
On certain conditions, if users intent to leave the current view (e.g. pop the current view, push other view, or select other tab items etc.), a UIAlertController should be presented to confirm users' real intention.
Users can press OK to proceed the view transitioning, or Cancel to stay on the current view.
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
if someConditions {
promptUIAlert()
}
}
Any solutions that can achieve that requirements?
First of all, you cannot handle this is viewWillDisappear because at this point it has already been decided that the view will disappear. You need to handle this wherever you have view transitions (push, pop, present, dismiss).
You have to handle the transitions in the confirmation alert action. You alert would look something like this.
let alert = UIAlertController(title: "Wait!", message: "Are you sure you want to leave this view?", preferredStyle: .alert)
let ok = UIAlertAction(title: "OK", style: .default) { (alertAction) in
//Handle view transitioning here
}
let cancel = UIAlertAction(title: "Cancel", style: .destructive) { (alertAction) in
//Do nothing?
}
alert.addAction(ok)
alert.addAction(cancel)
present(alert, animated: true, completion: nil)
You can't intercept and retain the user in the same ViewController once the viewWillDissaper is fired. You should do it in advance. My suggestion is to add a UIBarButton with a label Back to the navigationItem.leftBarButtonItem and manually check whether the user wants to navigate or not. This is the closest you can get.
also, you can use the UIAlertViewController to confirm whether the user wants to navigate or not.
//inside viewDidLoad
navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Back", style: .plain, target: self, action: #selector(handleBack))
//define another function to handle the selctor
#objc func handleCancel(){
if someConditions {
promptUIAlert()
}
}
//you function should be like this with UIAlertController
func promptUIAlert(){
let alertController = UIAlertController(title: "Error", message: "Some message", preferredStyle: .alert)
let CancelAction = UIAlertAction(title: "Cancel", style: .default) { (action) in
//type your custom code here for cancel action
}
let OkAction = UIAlertAction(title: "OK", style: .default) { (action) in
//type your custom code here for OK action
}
alertController.addAction(OKAction)
alertController.addAction(CancelAction)
self.present(alertController, animated: true)
}
Doing something inside viewWillDissaper would be handy to save some unsaved data behind the screen. But not to prompt and ask the user whether they want to remain in the same ViewController.
I have a childViewController which is pushed from parentViewController. In childViewController I want to block pop action in a particular condition.
I wrote this code in viewWillDisappear: But I guess need to do this somewhere else.
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
if changesMade {
let alertController = UIAlertController(title: "Alert", message: "Changes made are not saved. Do you wish to save changes made?", preferredStyle: .alert)
let cancelOption = UIAlertAction(title: "Cancel", style: .cancel)
let saveOption = UIAlertAction(title: "Save", style: .default, handler: { (action) in
self.saveSession()
})
alertController.addAction(saveOption)
alertController.addAction(cancelOption)
present(alertController, animated: true)
}
}
Actually, there is a very simple solution: navigationItem.hidesBackButton = true - this will hide "BACK" button and disable swipe-to-back feature. 🤓
There are two cases here:
User can pop using back button.
User can pop using interactive pop gesture of navigation controller.
I think you should use a custom back button and name it Done and write your logic of showing alert on press of this button.
Using the custom back button would disable the interactive pop gesture by default and you will be spared from playing the dance of enabling/disabling interactivePopGesture on navigation controller.
block pop action till your changes are not saved like this
if changesMade {
let alertController = UIAlertController(title: "Alert", message: "Changes made are not saved. Do you wish to save changes made?", preferredStyle: .alert)
let cancelOption = UIAlertAction(title: "Cancel", style: .cancel)
let saveOption = UIAlertAction(title: "Save", style: .default, handler: { (action) in
self.saveSession()
self.navigationController?.popViewController(animated: true)
})
alertController.addAction(saveOption)
alertController.addAction(cancelOption)
present(alertController, animated: true)
}
Update - Add this below custom button and its action in child View controller which is being pushed from parent View Controller
so, without satisfying your condition user can not move from child to parent again
For customising action of navigation backButton you need to manually add a back Button using below line , you can Customise barButton being added here in DidLoad
self.navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Back", style: UIBarButtonItemStyle.plain, target: self, action: #selector(self.backToInitial(sender:)))
It will perform required Action
#objc func backToInitial(sender: AnyObject) {
if changesMade {
let alertController = UIAlertController(title: "Alert", message: "Changes made are not saved. Do you wish to save changes made?", preferredStyle: .alert)
let cancelOption = UIAlertAction(title: "Cancel", style: .cancel)
let saveOption = UIAlertAction(title: "Save", style: .default, handler: { (action) in
self.saveSession()
self.navigationController?.popViewController(animated: true)
})
alertController.addAction(saveOption)
alertController.addAction(cancelOption)
present(alertController, animated: true)
}
}
and I do not think you can stop default back button action task of navigation Controller as it is designed the way to perform it
But yes you can manage it in ViewWillDisappear as :
override func viewWillDisappear(_ animated: Bool) {
if self.isMovingFromParentViewController || self.isBeingDismissed {
self.navigationController?.popViewController(animated: false) //here task but will not result as Expected output
}
}
-----------------Re-Update ---------------
in swift I used a objective-C class to get output as expected now, childViewController pop action is being controller from a alert using default back button that we get from navigation controller
You can customise you pop action to perform or not until your condition is not satisfied
Github Link - https://github.com/RockinGarg/NavigationBackButton.git
I found a much more elegant solution (in my opinion).
It works no matter how the user triggers the pop (accessibility escape, swipe back gesture, tapping back) since it overrides the built in pop methods that the system uses.
Swift 5
public class DiscardSafeNavigationController:UINavigationController {
/// Should the pop be prevented? Set this to `true` when you have changes which need to be protected
public var hasUnsavedChanges:Bool = false
/// Show a prompt on the top most screen asking the user if they wish to proceed with the pop
/// - Parameter discardCallback: The callback to use if the user opts to discard
private func confirmDiscardChanges(discardCallback:#escaping (()->())) {
let alertController = UIAlertController.init(title: "Discard changes", message: "Are you sure you want to discard any unsaved changes?", preferredStyle: UIAlertController.Style.alert)
alertController.addAction(UIAlertAction.init(title: "Discard", style: UIAlertAction.Style.destructive, handler: { (_) in
discardCallback()
//User elected to discard and so, at this point, they no longer have changes to save
self.hasUnsavedChanges = false
}))
alertController.addAction(UIAlertAction.init(title: "Cancel", style: UIAlertAction.Style.cancel, handler: nil))
self.topViewController?.present(alertController, animated: true, completion: nil)
}
override func popViewController(animated: Bool) -> UIViewController? {
//If there aren't unsaved changes, popping is safe
if !hasUnsavedChanges {
return super.popViewController(animated: animated)
}else {
//Changes have been made. Block the pop and first check with the user before continuing
confirmDiscardChanges {
super.popViewController(animated: animated)
}
return nil
}
}
}
and when you want to enable discard protection from any child view controllers, simply use:
(self.navigationController as? DiscardSafeNavigationController)?.hasUnsavedChanges = true
and then any time the navigation controller is asked to pop it, the navigation controller will ask the user first.
I would like to prevent the UIAlertController from dismissing.
I have a UIAlertAction that simply appends a string into the UIAlertTextField, however, once tapped it dismisses the view controller [undesired]. I've tried adding an NSNotification with undesired results.
UIAlertAction *pasteMessage = [UIAlertAction actionWithTitle:#"Paste Message" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
UITextField *textField = alertC.textFields.firstObject;
textField.text = [textField.text stringByAppendingString:[NSString stringWithFormat:#"%#", copiedString]];
}];
I've also tried setting no to pasteMessage by:
[alertC canPerformAction:#selector(dismissViewControllerAnimated:completion:) withSender:pasteMessage];
-(void)dismissViewControllerAnimated:(BOOL)flag completion:(void (^)(void))completion {
UIAlertController *alertController = (UIAlertController *)self.presentedViewController;
UIAlertAction *paste = alertController.actions.firstObject;
if (paste) {
flag = NO;
} else {
flag = YES;
}
}
Edit, i'm not looking to prevent the tapping of UIAlertAction i'm looking to prevent the UIAlertController from dismissing when tapping on said action. The action can be enabled/disabled whatever, but my goal is to simply paste the copied message into the UITextField by pressing an action (hence the reason I don't want it to be dismissed)
I also realize setting the BOOL to dismissViewControllerAnimated: simply sets it to not animate the view controllers dismissal, I don't want it to imply it was for stopping the actual dismissal process. Simply offering the things I've tried in relation to my goal. I've also tried presenting a new UIAlertController when selecting pasteMessage auto-populating the new UIAlertControllers textField with the copied message, it works, but I feel like it's too hacky for what could be done.
EDIT: Updated for Swift 5
EDIT: Updated to include #skywalker's feedback
So I actually got this to work. In short, it involves adding a long-press gesture recognizer to the UIAlertController that triggers before the dismissal occurs.
First, create lazily loaded computed variables in your view controller for your UIAlertController and the UIAlertAction you want to prevent from triggering so that self is accessible via the gesture recognizer's selector method you'll be attaching to the alert (self in the selector insinuates that all of this is inside a view controller).
lazy var alert: UIAlertController = {
let alert = UIAlertController(title: "Title", message: "Message", preferredStyle: .alert)
alert.addTextField(configurationHandler: nil)
let appendAction = self.appendAction
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
alert.addAction(appendAction)
alert.addAction(cancelAction)
let gestureRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(append(sender:)))
gestureRecognizer.minimumPressDuration = 0.0
alert.view.addGestureRecognizer(gestureRecognizer)
return alert
}()
lazy var appendAction: UIAlertAction = {
return UIAlertAction(title: "Paste Message", style: .default, handler: nil)
}()
Make sure your gesture recognizer above is a UILongPressGestureRecognizer set with a minimum press duration of 0. That way you can access the state of the gesture (for when the user touches down) before the action is triggered fully. There you can disable the UIAlertAction, implement your custom code, and reenable the action after the gesture has completed (user has touched up). See below:
#objc func append(sender: UILongPressGestureRecognizer) {
switch sender.state {
case .began:
appendAction.isEnabled = false
case .ended:
// Do whatever you want with the alert text fields
print(alert.textFields?[0].text)
appendAction.isEnabled = true
default:
return
}
}
Also, make sure that the view controller owning the presentation of this alert conforms to UIGestureRecognizerDelegate in order to recognize simultaneous gestures.
extension YourViewController: UIGestureRecognizerDelegate {
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
}
Then, just present the UIAlertController wherever.
func showAlert() {
self.present(alert, animated: true, completion: nil)
}
This is obviously a hack, but there's no other way that I know to achieve this without a hack since it's not meant to be achieved. For example, the gesture recognizer is tied to the UIAlertController so the user can trigger that method if they tap anywhere on the alert (besides the cancel button).
ORIGINAL ANSWER:
This is as close as I could come to a hack-a-round. If there was some way to customize the dismissal transition time to nothing then you could set animated: to false and it would look like the same alert, but I don't think it's possible
class ViewController: UIViewController {
#IBAction func alert(sender: AnyObject) {
let alert = UIAlertController(title: "title", message: "message", preferredStyle: .Alert)
alert.addTextFieldWithConfigurationHandler(nil)
let appendAction = UIAlertAction(title: "Append text", style: .Default) { _ in
var textField = alert.textFields![0] as UITextField
// Append text here
self.presentViewController(alert, animated: true, completion: nil)
}
let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel, handler: nil)
alert.addAction(appendAction)
alert.addAction(cancelAction)
self.presentViewController(alert, animated: true, completion: nil)
}
}
I'm only familiar with swift
Pretty much the same question is answered here
Text field on alert supports paste option, so there is no real reason to have separate button on alert to indicate "paste" option.
Otherwise you should mimic UIAlertController and reimplement it with desiread behavior.