I'm trying to detect when the users tap on the "Add" button in the PKAddPassesViewController.
I added addPassesViewControllerDidFinish() so that when passVC is dismissed, function addPassesViewControllerDidFinish() will be called.
override func viewDidLoad() {
self.pass = try PKPass(data: downloadedData! as Data)
let passVC = PKAddPassesViewController(pass: self.pass)
self.present(passVC!, animated: true)
// when passVC is dimissed by the user, addPassesViewControllerDidFinish is expected to be called, but it never gets called.
}
func addPassesViewControllerDidFinish(_ controller: PKAddPassesViewController) {
print("enter DidFinish")
let passLib = PKPassLibrary()
// Get your pass
guard let pass = self.pass else { return }
if passLib.containsPass(pass) {
print("if start")
// Show alert message for example
let alertController = UIAlertController(title: "", message: "Successfully added to Wallet", preferredStyle: .alert)
alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: { _ in
controller.dismiss(animated: true, completion: nil)
}))
controller.show(alertController, sender: nil)
print("if end")
} else {
// Cancel button pressed
print("else start");
controller.dismiss(animated: true, completion: nil)
print("else end");
}
}
However, when passVC is dimissed by the user, func addPassesViewControllerDidFinish() never gets called at all.
There are three things you should fix:
1. Extend PKAddPassesViewControllerDelegate in your ViewController class.
2. Double check if you added delegate to your PKAddPassesViewController: VC?.delegate = self, which will link your delegate to PKAddPassesViewControllerDelegate.
3. Inside addPassesViewControllerDidFinish, dismiss controller first. Then do whatever you want inside passLib.containPass. The alertController is no longer belonged to the controller, maybe to its parent view.
Related
I got simple UIViewController + UIAlert extension:
extension UIViewController {
func alert(title: String = "", message: String){
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: Localized.ok(), style: .default, handler: nil))
present(alert, animated: true, completion: nil)
}
}
Within the ViewController I got a method:
func findUser() {
userService.findUser { (userinfo, error) in
if error != nil {
if let errText = error?.localizedDescription {
self.alert(message: errText)
}
self.doAuth()
return
}
}
}
this doAuth() method should redirect to loginViewController using:
navigationController?.pushViewController(loginViewController, animated: false)
The problem is, that in this scenario, this push doesn't work (nothing appears) (I click OK button on the alert, alert dissapears but loginViewController is not pushed)
I refactored extension a little bit:
extension UIViewController {
func alert(title: String = "", message: String, action completion: (() -> Void)? = nil){
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: Localized.ok(), style: .default, handler: { _ in
completion?()
}))
present(alert, animated: true, completion: nil)
}
}
so findUser() method is calling doAuth() in differently:
func findUser() {
userService.findUser { (userinfo, error) in
if error != nil {
if let errText = error?.localizedDescription {
self.alert(message: errText){ [weak self] in
self?.doAuth()
}
}
return
}
}
}
and it works!
Problem is I have no idea why. And what could have happened in the first scenario?
I feel it should be some simple explanation, but I can't figure it out.
Edit
The explanation is simple and was printed in the console:
pushViewController:animated: called on <UINavigationController 0x7f86050b4400>
while an existing transition or presentation is occurring; the navigation stack
will not be updated.
So doAuth() (with pushing VC method) was called while alert was visible/presented, so alert took the focus and VC couldn't be pushed.
cc: #Paulw11 # cookednick
Problem is navigating and presenting in same if statement
If error != nil , means it only show the alert not try to doAuth().
But you are calling doAuth() in same if block then it is trying to present alert as well as to navigate
func findUser() {
userService.findUser { (userinfo, error) in
if error != nil {
if let errText = error?.localizedDescription {
self.alert(message: errText)
}
return
}
//Out side if block
self.doAuth()
}
}
I have an app where a user uploads a file in the background that usually takes a couple of seconds. The upload is kicked off when they tap a "Done" button and that also dismisses the view controller. What I would I would like to happen is an alert comes up when the download is done. I thought I would just add the code below to the upload function but it isn't working. How can I have an alert box appear to confirm that that the upload was successful?
#IBAction func tapDone(_ sender: Any) {
self.dismiss(animated: true, completion: nil)
if let image = newImage {
submit2Parse(image: image)
}
}
func submit2Parse (image: UIImage) {
if let pfImage = image2PFFile(image: image) {
// Insert PFFile into parse server
let submittedImage = PFObject(className: "Images")
submittedImage["imageFile"] = pfImage
submittedImage["type"] = "submittedFromUserHome"
submittedImage["bride"] = brideSwitch.isOn
submittedImage["groom"] = groomSwitch.isOn
submittedImage["user"] = userSwitch.isOn
submittedImage["picturePeriod"] = pickerSelected
submittedImage["uploadedByUserId"] = PFUser.current()?.objectId ?? "" submittedImage["uploadedByUserName"] = PFUser.current()?.username ?? ""
if !txtIsPlaceHolder { submittedImage["description"] = imageDescription.text }
submittedImage.saveInBackground { (success, error) in
if success {
let message = "Save in bg worked"
print(message)
let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertAction.Style.default, handler: {
(action) in
self.dismiss(animated: true, completion: nil)
}))
self.present(alert,animated: true, completion: nil)
} else {
print(error?.localizedDescription ?? "")
}
}
}
}
The code gives me this build error:
Implicit use of 'self' in closure; use 'self.' to make capture semantics explicit
In your tapDone method, you need to utilize the completion of the dismissal of your controller, like so:
self.dismiss(animated: true) {
if let image = newImage {
self.submit2Parse(image: image)
}
}
This only means that the self.submit2Parse(image: image) will ONLY be executed after you dismiss the controller. Additionally, the error
Implicit use of 'self' in closure; use 'self.' to make capture
semantics explicit
only means that you need to use self. to explicitly call a variable or method when you're inside a closure. So your submit2Parse... would now be like this:
self.submit2Parse(image: image).
If I understood your question correctly you want to dismiss your SecondViewController when user tap on tapDone button. And after that once your image upload complete then you want to present alert for success.
But if you dismiss it once button tapped you won't get any alert because your SecondViewController is no longer in window hierarchy and if you will try to present the alert you will get an error in Console like:
Attempt to present on
whose view is not in the
window hierarchy!
To solve this problem you need to present a alert from your first view controller which will appear after you dismiss your second view controller and you can achieve it with delegate.
Consider the below example:
First of all declare a protocol outside your FirstViewController:
protocol UplaodSuccessDelegate:class {
func uploadSuccess(message: String)
}
then confirm your delegate to same class:
class ViewController: FirstViewController, UplaodSuccessDelegate {
then you need to pass the delegate when you present SecondViewController:
let vc = self.storyboard?.instantiateViewController(withIdentifier: "SecondViewController") as! SecondViewController
vc.delegate = self. //Pass delegate
self.present(vc, animated: true, completion: nil)
and add delegate method to same class:
func uploadSuccess(message: String) {
let message = "Save in bg worked"
print(message)
let alert = UIAlertController(title: "title", message: message, preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertAction.Style.default, handler: {
(action) in
}))
self.present(alert,animated: true, completion: nil)
}
now in your SecondViewController you need to add
weak var delegate: UplaodSuccessDelegate?
and in your tapDone method replace a code with:
self.dismiss(animated: true) {
if let image = newImage {
submit2Parse(image: image)
}
}
and once your upload complete you need to call delegate method (once your upload completes) like:
self.delegate?.uploadSuccess(message: "your message")
This will call your delegate method from FirstViewController.
When you drop the function below into the viewController that initiates the data upload in the background, and then call this function in the closure that fires when the submit completes it is able to successfully create an alert even thought the initial view controller was dismissed (or long dismissed if it was a long upload).
// This is the function that performs my background upload
func submit2Parse (image: UIImage) {
if let pfImage = image2PFFile(image: image) {
// Insert PFFile into parse server
let submittedImage = PFObject(className: "Images")
submittedImage["imageFile"] = pfImage
submittedImage["imageCreateDt"] = newImageCreateDate
submittedImage["type"] = "submittedFromUserHome"
submittedImage["bride"] = brideSwitch.isOn
submittedImage["groom"] = groomSwitch.isOn
submittedImage["user"] = userSwitch.isOn
submittedImage["picturePeriod"] = pickerSelected
submittedImage["uploadedByUserId"] = PFUser.current()?.objectId ?? ""
submittedImage["uploadedByUserName"] = PFUser.current()?.username ?? ""
if !txtIsPlaceHolder { submittedImage["description"] = imageDescription.text }
// Get the image timestamp, every photo has one
// How do you get the thumbnail image too?
submittedImage.saveInBackground { (success, error) in
if success {
let message = "Save in bg worked"
print(message)
self.showAlertFromAppDelegates()
} else {
print(error?.localizedDescription ?? "")
}
}
}
}
// This is the function that creates the alert
func showAlertFromAppDelegates(){
var topWindow: UIWindow? = UIWindow(frame: UIScreen.main.bounds)
topWindow?.rootViewController = UIViewController()
topWindow?.windowLevel = UIWindow.Level.alert + 1
let alert: UIAlertController = UIAlertController(title: "Upload Complete", message: "Your image was successfully submitted!", preferredStyle: .alert)
alert.addAction(UIAlertAction.init(title: "OK", style: .default, handler: { (alertAction) in
topWindow?.isHidden = true
topWindow = nil
}))
topWindow?.makeKeyAndVisible()
topWindow?.rootViewController?.present(alert, animated: true, completion:nil)
}
I have one scenario when the user did not use the application for more than 5 min app will show a popup with session expiration message.
The code for session expiration is added in the appDelegate and from there the popup will be presented on the current view controller.
code is
#objc func applicationDidTimeout(notification: NSNotification) {
if (window?.rootViewController?.isKind(of: UITabBarController.self))! {
for view in window?.rootViewController?.view.subviews ?? [(window?.rootViewController?.view)!] {
if view.isKind(of: MBProgressHUD.self) {
return
}
}
if window?.rootViewController?.presentedViewController != nil {
window?.rootViewController?.dismiss(animated: true, completion: {
self.showMessage(message: Message.sessionTimeout)
})
} else {
self.showMessage(message: Message.sessionTimeout)
}
}
}
fileprivate func showMessage(message: String) {
let alert = UIAlertController(title: appName, message: message, preferredStyle: .alert)
let actionOkay = UIAlertAction(title: "OK", style: .default) { (action) in
DispatchQueue.main.async {
UIView.transition(with: self.window!, duration: 0.3, options: UIView.AnimationOptions.transitionCrossDissolve, animations: {
CommonFunctions.setLoginAsRootVC()
}, completion: nil)
}
}
alert.addAction(actionOkay)
self.window?.rootViewController?.present(alert, animated: true, completion: nil)
}
Now if the user is doing some data entry and at that time, if the user leaves application ideal for 5 min or more the keyboard will dismiss and the session expiration message shown there.
But as the text field's delegate method textFieldShouldEndEditing has some validation and if that validation fails it shows a popup with the message and ok button.
So when the user taps on the ok button in the session expiration message popup, it will redirect the user to the login screen but due to the text field's delegate method validation, it shows one pop up in the login screen.
Code for the validation fail message popup is
fileprivate func showErrorMessage(message: String) {
let alert = UIAlertController(title: appName, message: message, preferredStyle: .alert)
let actionOkay = UIAlertAction(title: "OK", style: .default) { (action) in
self.txtField.becomeFirstResponder()
}
alert.addAction(actionOkay)
self.present(alert, animated: true, completion: nil)
}
How to prevent the popup from being present in the login screen?
I try to get the proper way to prevent the popup from appearing on the login screen.
But Finally, I found one heck to solve this issue.
I have declared one boolean in AppDelegate and set it's value to false when I want to prevent the popup from appearing and then revert it back to true when I want to show the popup.
I know this is not the elegant or efficient solution for the issue, but it works for now.
If anyone knows the better answer can post here, I'm still open to any better solution.
#objc func applicationDidTimeout(notification: NSNotification)
{
let visibleView : UIViewController = self.getVisibleViewControllerFrom(self.window?.rootViewController)!
self.showMessage(message: Message.sessionTimeout,Controller: visibleView)
}
fileprivate func showMessage(message: String , Controller : UIViewController) {
let alert = UIAlertController(title: appName, message: message, preferredStyle: .alert)
let actionOkay = UIAlertAction(title: "OK", style: .default) { (action) in
//Now apply your code here to set login view controller as rootview
// This controller is for demo
window!.rootViewController = UIStoryboard(name: "Main", bundle:
nil).instantiateViewController(withIdentifier: "loginview")
window!.makeKeyAndVisible()
}
alert.addAction(actionOkay)
Controller.present(alert, animated: true, completion: nil)
}
//MARK:- Supporting method to get visible viewcontroller from window
func getVisibleViewControllerFrom(_ vc: UIViewController?) -> UIViewController? {
if let nc = vc as? UINavigationController {
return self.getVisibleViewControllerFrom(nc.visibleViewController)
} else if let tc = vc as? UITabBarController {
return self.getVisibleViewControllerFrom(tc.selectedViewController)
} else {
if let pvc = vc?.presentedViewController {
return self.getVisibleViewControllerFrom(pvc)
} else {
return vc
}
}
}
Try this code, I've use this code many times may be it's work for you.
I declared a global variable for UIAlertViewController for me to be able to show and dismiss it in different method inside my class.
I displayed two kinds of alert: First, alert with button which will be displayed when an error is encountered or to display an information message. Second is an alert without button which will be displayed like a progress message.
Here is the sample code:
private var alert: UIAlertController? // global declaration
private func showProgressMessage(sender viewController: UIViewController, message alertMessage: String)
{
DispatchQueue.main.async
{
self.alert= UIAlertController(title: "", message: alertMessage, preferredStyle: .alert)
viewController.present(self.alert!, animated: true, completion: nil)
}
}
private func showAlertMessage(sender viewController: UIViewController, title alertTitle: String, message alertMessage: String)
{
DispatchQueue.main.async
{
self.alert= UIAlertController(title: alertTitle, message: alertMessage, preferredStyle: .alert)
self.alert!.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
viewController.present(self.alert!, animated: true, completion: nil)
}
}
private func method1()
{
DispatchQueue.global().async
{
// some code here
self.showProgressMessage(sender: self, message: "Processing...")
// some code here
}
}
private func method2()
{
// some code here
self.alert!.dismiss(animated: false)
{
self.showAlertMessage(sender: self, message: "Done")
}
self.displayOtherViewController()
}
private func displayOtherViewController()
{
self.alert?.dismiss(animated: false)
{
if let viewController = self.storyboard?.instantiateViewController(withIdentifier: "Sample")
{
let view = viewController as! SampleViewController
view .modalTransitionStyle = .crossDissolve
self.present(view , animated: true, completion: nil)
}
}
}
In method2, displaying the alert again will take a few seconds to display, same with the view controller.
What is the proper way to show and dismis the UIAlertController in Swift 4?
Seems like your code is initiated from a background thread.
Even dismiss must be called on main thread
Try this:
private func method2() {
DispatchQueue.main.async {
self.alert!.dismiss(animated: false) {
self.showAlertMessage(sender: self, message: "Done")
}
self.displayOtherViewController()
}
}
I've got a Problem. I'm new to iOS programming, and i'm struggling to understand how Swift code is excecuted. For example, in the piece of code below, I would think that every line is executed right after the one above. But when it reaches the passData() function, it does not ejecute that fuction. it keeps going, and some time later (or erlier) it excecutes it (the passData function).
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
if numLaunches == 0{
nombre = usuario()
numLaunches += 1
}
}
func usuario() -> String {
var tField: UITextField!
func configurationTextField(textField: UITextField!)
{
print("generating the TextField")
textField.placeholder = "Enter an item"
textField.textAlignment = .center
tField = textField
}
func handleCancel(alertView: UIAlertAction!)
{
print("Cancelled !!")
}
let alert = UIAlertController(title: "Please Enter Your Name", message: "", preferredStyle: .alert)
alert.addTextField(configurationHandler: configurationTextField)
alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler:handleCancel))
alert.addAction(UIAlertAction(title: "Done", style: .default, handler:{ (UIAlertAction) in
print("Done !!")
print("Item : \(String(describing: tField.text))")
self.nombre = tField.text!
}))
self.present(alert, animated: true, completion: {
print("completion block")
})
print(self.nombre)
passData()
if tField.text == nil {
return "No value"
}else{
return (tField.text!)
}
}
func passData() {
let myVC = storyboard?.instantiateViewController(withIdentifier: "SecondVC") as! AboutViewController
if myVC.playerName != nil {
myVC.playerName.text = nombre
}else{
}
navigationController?.pushViewController(myVC, animated: true)
print("pasa el dato")
}
So, the Problem is, that i need to pass the content of the variable "nombre" to another VC. But when the passData function is excecuted that variable is empty. I thought if i called that function after the variable was updated, it Will pass the right content. But im clearly mistaken.
I would appreciate the help!
In general, unless your functions are asynchronous, you are correct in your understanding that code is executed from top down. In this case I think you are just confused about your UIAlertAction code. It appears you are popping an alert to the user, asking them to write their name, and when they hit "Done" you want to call your passData() function. In that case, you should put that passData() call inside your UIAlertAction, like so:
alert.addAction(UIAlertAction(title: "Done", style: .default, handler:{ (UIAlertAction) in
print("Done !!")
print("Item : \(String(describing: tField.text))")
self.nombre = tField.text!
self.passData()
}))
The code inside the handler for your UIAlertActions will not be executed until the user presses that button, which is why you are finding that passData is getting called too early.