I use UIAlertController in my app and whenever the user clicks OK, it takes the user back to the first viewcontroller.
var activityIndicator: UIActivityIndicatorView = UIActivityIndicatorView()
func displayAlert(title:String, error: String){
var alert = UIAlertController(title: title, message: error, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: .Default, handler: { action in
self.dismissViewControllerAnimated(true, completion: nil)
}))
self.presentViewController(alert, animated: true, completion: nil)
}
I use the function above to show the alert at any point on the viewcontroller.
What does that happen? How can I keep the user on the current viewcontroller?
In your action you are calling self.dismissViewController - in this context "self" is the current view controller, not your alert view, so you are actually requesting the removal of the current view controller.
Related
#IBAction func addButton(sender: AnyObject) {
let alert = UIAlertController(title: "New Exercise Added", message: "\(name)", preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Ok!!", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)
self.navigationController?.popToRootViewControllerAnimated(true)
self.dismissViewControllerAnimated(true, completion: {})
}
Within the IB action function of a button I have an alert, followed by some code to change to a different ViewController.
The program crashes upon reaching these lines of code after the alert:
2016-01-04 17:48:27.147 FitnessApp[60584:4080964] popToViewController:transition: called on while an existing transition or presentation is occurring; the navigation stack will not be updated.
How do I run the code to change ViewController after the transition is done?
Your biggest issue is that you don't do anything with the alert button's handler. Instead, you immediately try to do the pop and dismiss after presenting the alert.
Move the code to pop the controller into the Ok button's alert handler.
#IBAction func addButton(sender: AnyObject) {
let alert = UIAlertController(title: "New Exercise Added", message: "\(name)", preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Ok!!", style: UIAlertActionStyle.Default, handler: {
self.navigationController?.popToRootViewControllerAnimated(true)
// You only need the pop
//self.dismissViewControllerAnimated(true, completion: {})
}))
self.presentViewController(alert, animated: true, completion: nil)
}
Note: I'm not fluent in Swift so the syntax could be off a little.
I have this function and I use it on almost all viewController´s that I have, for some reason went I push "ok" to dismiss the pop up, it switches to another viewController.
this is my function...
extension UIViewController
{
func displayAlert(title: String, message: String)
{
let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction((UIAlertAction(title: "Ok", style: .Default, handler:
{ (action) -> Void in
self .dismissViewControllerAnimated(true, completion: nil)
})))
self.presentViewController(alert, animated: true, completion: nil)
}
}
any help? I'm using Xcode 7.0 beta 6 with swift 2
You don't need to dismiss the alert controller yourself. That happens automatically with your alert action. You're simply providing a closure that gets called when that "OK" action gets triggered. Just remove this line:
self.dismissViewControllerAnimated(true, completion: nil)
I have a view controller which is modally presented and when i run UIAlertController, keep getting a error message . how can i work around this.
the alert is trigged from a button which checks a text field is empty or not.
#IBAction func registerAction(sender: AnyObject) {
if(userEmail.isEmpty){
alertMessage("Fields Are Empty")
}
}
func alertMessage(userMessage:String){
var myAlert = UIAlertController(title: "Alert", message: userMessage, preferredStyle: UIAlertControllerStyle.Alert)
let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil)
myAlert.addAction(okAction)
self.presentViewController(myAlert, animated: true, completion: nil)
}
Error when i run the alert
Warning: Attempt to present <UIAlertController: 0x7f9bbb9060d0> on <AlertApp.CustomSignupVC: 0x7f9bb94accb0> which is already presenting <UIAlertController: 0x7f9bbb926660>
Try to add it in main operation queue.
dispatch_async(dispatch_get_main_queue()) {
self.presentViewController(myAlert, animated: true, completion: nil)
}
Check this relative question : Presenting a view controller modally from an action sheet's delegate in iOS8 - iOS10
I wrote the following function below to display alerts through my project. Every time i check for an error in a form i display the alert when the user clicks submit. I want to simply show the alert, but not unwind the pervious segue. I want to stay at the current screen and give the user the opportunity to complete the form. Right now when the user clicks submit, it displays the alert ..but when i click the ok button to dismiss the alert it immediately unwinds the segue to the previous screen.
I have included the UIAlertViewDelegate in the class.... any ideas why this might be happening?
func displayAlert(title:String, error:String) {
var alert = UIAlertController(title: title, message: error, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: .Default, handler: { action in
self.dismissViewControllerAnimated(true, completion: nil)
}))
self.presentViewController(alert, animated: true, completion: nil)
}
Never mind.
func displayAlert(title:String, error:String) {
var alert = UIAlertController(title: title, message: error, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: .Default, handler: { action in
//comment out this line and it will still work. It will not segue back to the previous screen.
//self.dismissViewControllerAnimated(true, completion: nil)
}))
self.presentViewController(alert, animated: true, completion: nil)
}
When using UIAlertController like this:
var alert = UIAlertController(title: "Core Location",
message: "Location Services Disabled!",
preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default,
handler: nil))
self.navigationController.presentViewController(alert, animated: true,
completion: nil)
I noticed that the dismissal of the alert view is seemingly done automatically.
Shouldn't the dismissal of a presented ViewController be done by the presenting ViewController via a delegate call?
The dismissal is "included" in the presentViewController call. You do not need a delegate because you have the completion block. In this block you put what you would normally put into the delegate callback, except the call to dismiss the alert.
As far as "best practice" is concerned, I noted that in many APIs, Apple replaced delegate callbacks with completion blocks. Apple typically recommends using the block syntax. I surmise this could be partly because it helps keeping the related code sections together.
Is some Cases you may like to use this:
class MyAlertController : UIAlertController {
var dismissHandler : (()->())?
override func viewDidDisappear(_ animated: Bool) {
dismissHandler?()
super.viewDidDisappear(animated)
}
}
Usage:
let alert = MyAlertController(title: ...
let cancelButton = UIAlertAction(titl
alert.dismissHandler = { /*...do something */ }
alert.addAction(cancelButton)
...
There is an elegant way! Just write the action or function inside the alert controller's cancel action. (here the action style should be .cancel)
Code for Swift 3:
let Alert: UIAlertController = UIAlertController(title: nil, message: nil, preferredStyle: UIAlertControllerStyle.actionSheet)
let OkAction: UIAlertAction = UIAlertAction(title: “Ok”, style: .default) { ACTION in
//Will be called when tapping Ok
}
let CancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .cancel) {ACTION in
// Will be called when cancel tapped or when alert dismissed.
// Write your action/function here if you want to do something after alert got dismissed”
}
Alert.addAction(OkAction)
Alert.addAction(CancelAction)
present(Alert, animated: true, completion: nil)