iOS Swift - Unable to trigger segue - ios

I have the below code which shows an alert box when user signs up. After the user interacts with the Alert Box button (i.e. let's go), I have a segue I need triggered (called someSegue for now) so that it can redirect the user to login page.
Nothing is happening after user clicks alert box button. What am I missing? is it the self there? if I remove the self it doesn't work and xcode complains.
user.signUpInBackgroundWithBlock {
(succeeded, error) -> Void in
if error == nil {
// Hooray! Let them use the app now.
let delay = 4.5 * Double(NSEC_PER_SEC)
let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))
dispatch_after(time, dispatch_get_main_queue()) {
actInd.stopAnimating()
var alert = UIAlertController(title: "Congratulations!", message: "Your account was successfully created! You will be required to login with your credentials.", preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Let's Go!", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)
self.performSegueWithIdentifier("someSegue", sender: self)
}
} else {
// Show the errorString somewhere and let the user try again.
}
}

If you want to execute a block of code after alert button is pressed you need to pass that block in handler parameter of addAction method
alert.addAction(UIAlertAction(title: "Let's Go!", style: UIAlertActionStyle.Default, handler: { (action: UIAlertAction!) in
self.performSegueWithIdentifier("someSegue", sender: self)
}))

Related

Swift: How to make an action occur if UIAlertAction is pressed?

I'm trying to make an app where if the score is 3 the app displays a message that says "you lose" but keeps '3' as the number in the score label until the End Game option in the popup is pressed, at which point the score goes back to 0 for a new game. I am new to swift and am having difficulty and would really appreciate any and all help! I am not sure if making an IBAction for the alert action is the right thing to do or not.
else if rightscorecount == 3 {
let alert = UIAlertController(title: "Game", message: "You Lose!", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "End Game", style: UIAlertActionStyle.default) { UIAlertAction in})
self.present(alert, animated: true, completion: nil)
}
}
#IBAction func test(sender: UIAlertAction) {
rightscorecount = 0
rightscorelabel.text = String(rightscorecount)
}
Try this:
let alertController = UIAlertController.init(title: "Game", message: "You Lose!", preferredStyle: .alert)
alertController.addAction(UIAlertAction.init(title: "End Game", style: .default, handler: { (action) in
// Your handler goes here
self.someFunction()
}))
self.present(alertController, animated: true) {
// Completion block
}
And your function
func someFunction() {
// Function body goes here
}

Using UIAlertView to Cancel a Touch

I am building a game.
This game has a UITableViewController which serves as a Settings & Options feature.
One of the options that you can select is to switch the opponent from pass and play to an AI (or the other way around).
What I'd like to do is use a UIAlertController to intercept the touch, check for a game in progress, and prompt the user to cancel the change or continue.
I have implemented the code to do this within the override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) function.
My code is as follows:
if indexPath.section == 1 {
// Here we need to detect a game in progress and ask for a confirmation before switching to another mode.
if getGameInProgress() == true {
// Display choice dialog
alert = UIAlertController (title: alertCaption, message: alertMessage, preferredStyle: .Alert)
let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel, handler: {(action: UIAlertAction) -> Void in
self.alert.dismissViewControllerAnimated(true, completion: { _ in })
return
})
alert.addAction(cancelAction)
let ok: UIAlertAction = UIAlertAction(title: "Confirm", style: .Default, handler: {(action: UIAlertAction) -> Void in
self.alert.dismissViewControllerAnimated(true, completion: { _ in })
// Do nothing, just let the touch method continue...
})
alert.addAction(ok)
self.presentViewController (alert, animated: true, completion: nil)
}
if indexPath.row == 0 {
// "Pass and Play"
setOpponentPreference("Pass and Play")
}
if indexPath.row == 1 {
// "Virtual Robert"
setOpponentPreference("Virtual Robert")
}
if indexPath.row == 2 {
// "Virtual Nathan"
setOpponentPreference("Virtual Nathan")
}
// No matter which difficulty selected:
gameboard.setDifficulty()
// Create a method to reset the game, but without fading out the menu screen (the current new game method takes you directly to the game. The player may not want that in this instance.)
}
The problem I am having is that the alert controller displays and waits for input, but it does not prevent the rest of the didSelectRowAtIndexPath function form continuing.
How do I receive the users input before handling the touch on the cell?
Hello All you need is put your code inside of your completion section for your "Confirm" option, your code will be execute only when user tap on "Confirm" button of your UIAlertViewController
self.alert.dismissViewControllerAnimated(true, completion: { _ in })
// Do nothing, just let the touch method continue...
})
so your code must be
if indexPath.section == 1 {
// Here we need to detect a game in progress and ask for a confirmation before switching to another mode.
if getGameInProgress() == true {
// Display choice dialog
alert = UIAlertController (title: alertCaption, message: alertMessage, preferredStyle: .Alert)
let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel, handler: {(action: UIAlertAction) -> Void in
self.alert.dismissViewControllerAnimated(true, completion: { _ in })
return
})
alert.addAction(cancelAction)
let ok: UIAlertAction = UIAlertAction(title: "Confirm", style: .Default, handler: {(action: UIAlertAction) -> Void in
self.alert.dismissViewControllerAnimated(true, completion: { _ in })
if indexPath.row == 0 {
// "Pass and Play"
setOpponentPreference("Pass and Play")
}
if indexPath.row == 1 {
// "Virtual Robert"
setOpponentPreference("Virtual Robert")
}
if indexPath.row == 2 {
// "Virtual Nathan"
setOpponentPreference("Virtual Nathan")
}
// No matter which difficulty selected:
gameboard.setDifficulty()
// Create a method to reset the game, but without fading out the menu screen (the current new game method takes you directly to the game. The player may not want that in this instance.)
})
alert.addAction(ok)
self.presentViewController (alert, animated: true, completion: nil)
}
}
I hope this helps you, for me works great, regards
Sorry for the bad English. What I understand from you question is that you want to hold the program to continue execution till user select one of the button from UIAlertController.
for that you need to do is perform task inside the action of Ok button or Cancel button.
if getGameInProgress() == true {
// Display choice dialog
alert = UIAlertController (title: alertCaption, message: alertMessage, preferredStyle: .Alert)
let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel, handler: {(action: UIAlertAction) -> Void in
self.alert.dismissViewControllerAnimated(true, completion: { _ in })
return
})
alert.addAction(cancelAction)
let ok: UIAlertAction = UIAlertAction(title: "Confirm", style: .Default, handler: {(action: UIAlertAction) -> Void in
//Do something in here like print
println("Confirm Button Pressed")
self.alert.dismissViewControllerAnimated(true, completion: { _ in })
// Do nothing, just let the touch method continue...
})
alert.addAction(ok)
self.presentViewController (alert, animated: true, completion: nil)
}
hope it help.

presentViewController isn't modal in shouldPerformSegueWithIdentifier

I'm trying to make an unwind segue depend on the user approving it in an alert dialog. However, when I run the code the dialog just quickly appears, disappears, and segues to the other view controller. I've tried making the alertDialog an instance variable of the class and that doesn't make a difference. The code below is inside a UIViewController subclass. What am I missing?
Thanks.
override func shouldPerformSegueWithIdentifier(identifier: String, sender: AnyObject?) -> Bool {
var shouldPerformSeque = true
if identifier == "startOver" {
let alertDialog = UIAlertController(title: "Warning",
message: "This will discard all data entered.",
preferredStyle: .Alert)
let okAction = UIAlertAction(title: "OK", style: .Default, handler: nil)
alertDialog.addAction(okAction)
let cancelActionHandler = {
(action: UIAlertAction!) -> Void in
shouldPerformSeque = false
}
let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel,
handler: cancelActionHandler)
alertDialog.addAction(cancelAction)
presentViewController(alertDialog, animated: false, completion: nil)
}
return shouldPerformSeque
}
You can't do this in shouldPerformSegueWithIndentifier because the dialog will be presented asynchronously with regard to that method; by the time the action handler closure executes the method has already returned.
You need to display the dialog in response to whatever is triggering the segue and then perform the unwind programmatically depending on the user's response.

Prompting user to enter input through UIAlertController again after validation fails gives a WARNING on logs

I am using the following function to prompt user for email address.
The validateEmailAddress and validateVerificationCodeAgainstEmail call the function below, promptUserToEnterEmail, again if validation fails. The problem is that I get the Warning message shown below when the user is prompted again.
func promptUserToEnterEmail() {
var alertController:UIAlertController?
alertController = UIAlertController(title: "Enter Email Address",
message: "Please enter your email address.",
preferredStyle: .Alert)
alertController!.addTextFieldWithConfigurationHandler(
{(textField: UITextField!) in
textField.placeholder = "Email"
})
let action = UIAlertAction(title: "Submit",
style: UIAlertActionStyle.Default,
handler: {[weak self]
(paramAction:UIAlertAction!) in
if let textFields = alertController?.textFields{
let theTextFields = textFields as [UITextField]
let enteredText:UITextField = theTextFields[0]
print("prompted email: \(enteredText.text)")
// Validate email address
self!.validateEmailAddress(enteredText)
print("Returned from validateEmailAddress()");
// Continue to validate verification code against email address
self!.validateVerificationCodeAgainstEmail()
print("Returned from validateVerificationCodeAgainstEmail()");
}
})
alertController?.addAction(action)
let cancelItem = UIAlertAction(title: "Cancel", style: .Cancel, handler: nil)
alertController?.addAction(cancelItem)
self.presentViewController(alertController!,
animated: true,
completion: nil)
}
WARNING MESSAGE:
Warning: Attempt to present <UIAlertController: 0x7fe6f0eb4bb0>
on <XXXXXV1.ViewController: 0x7fe6f0cd7400> which is already presenting
<UIAlertController: 0x7fe6f0e3ea50>
Well if you are so hellbent on showing two alerts one after another then you can delay the second alert by a certain amount of time after the first one is displayed:
let delay = 10.0 * Double(NSEC_PER_SEC);
let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay));
dispatch_after(time, dispatch_get_main_queue(), {
//display the second alert here
})
Or you could dismiss the alert controller after the submit gives an error.
So you can display the first alert and after the submit button is pressed call the dismiss the firstAlert:
firstAlert.dismissViewControllerAnimated(true, completion: nil)
Once that is done, simply follow your current flow

Where to find a clear explanation about swift alert (UIAlertController)?

Couldn't find a clear and informative explanation for this.
After searching a while on a subject I didn't
find a clear explanation , even in it's class reference
UIAlertController Reference
It is ok, but not clear enough for me.
So after collecting some peaces I decided to make my own explanation
(Hope it helps)
So here it goes:
UIAlertView is deprecated as pointed out :
UIAlertView in Swift
UIAlertController should be used in iOS8+
so to create one first we need to instantiate it,
the Constructor(init) gets 3 parameters:
2.1 title:String -> big-bold text to display on the top of alert's dialog box
2.2 message:String -> smaller text (pretty much explains it's self)
2.3 prefferedStyle:UIAlertControllerStyle -> define the dialog box style, in most cases: UIAlertControllerStyle.Alert
Now to actually show it to the user, we can use showViewController or presentViewController and pass our alert as parameter
To add some interaction with a user we can use:
4.1
UIAlertController.addAction to create buttons
4.2
UIAlertController.addTextField to create text fields
Edit note: code examples below, updated for swift 3 syntax
Example 1: Simple Dialog
#IBAction func alert1(sender: UIButton) {
//simple alert dialog
let alert=UIAlertController(title: "Alert 1", message: "One has won", preferredStyle: UIAlertControllerStyle.alert);
//show it
show(alert, sender: self);
}
Example 2: Dialog with one input textField & two buttons
#IBAction func alert2(sender: UIButton) {
//Dialog with one input textField & two buttons
let alert=UIAlertController(title: "Alert 2", message: "Two will win too", preferredStyle: UIAlertControllerStyle.alert);
//default input textField (no configuration...)
alert.addTextField(configurationHandler: nil);
//no event handler (just close dialog box)
alert.addAction(UIAlertAction(title: "No", style: UIAlertActionStyle.cancel, handler: nil));
//event handler with closure
alert.addAction(UIAlertAction(title: "Yes", style: UIAlertActionStyle.default, handler: {(action:UIAlertAction) in
let fields = alert.textFields!;
print("Yes we can: "+fields[0].text!);
}));
present(alert, animated: true, completion: nil);
}
Example 3: One customized input textField & one button
#IBAction func alert3(sender: UIButton) {
// one input & one button
let alert=UIAlertController(title: "Alert 3", message: "Three will set me free", preferredStyle: UIAlertControllerStyle.alert);
//configured input textField
var field:UITextField?;// operator ? because it's been initialized later
alert.addTextField(configurationHandler:{(input:UITextField)in
input.placeholder="I am displayed, when there is no value ;-)";
input.clearButtonMode=UITextFieldViewMode.whileEditing;
field=input;//assign to outside variable(for later reference)
});
//alert3 yesHandler -> defined in the same scope with alert, and passed as event handler later
func yesHandler(actionTarget: UIAlertAction){
print("YES -> !!");
//print text from 'field' which refer to relevant input now
print(field!.text!);//operator ! because it's Optional here
}
//event handler with predefined function
alert.addAction(UIAlertAction(title: "Yes", style: UIAlertActionStyle.default, handler: yesHandler));
present(alert, animated: true, completion: nil);
}
Hope It helps, and good luck ;-)
An instance of the UIAlertController can be presented modally on screen just as any other UIViewController using the presentViewController:animated:completion: method. What makes the UIAlertController instance differentiate between working as an ActionSheet or as an AlertView is the style parameter you pass when creating it.
No more delegation
If you have used a UIActionSheet or UIAlertView, you know that the way to get a callback from it is for a class (in most cases the ViewController) to implement the UIActionSheetDelegate or UIAlertViewDelegate protocol. There are some open source projects that replaced this delegation pattern with block based callbacks, but the official APIs were never updated. UIAlertController does not use delegation. Instead, it has a collection of UIAlertAction items, that use closures (or blocks if you are using Objective-C) to handle user input.
For Action Sheet
#IBAction func showActionSheet(sender: AnyObject) {
//Create the AlertController
let actionSheetController: UIAlertController = UIAlertController(title: "Action Sheet", message: "Swiftly Now! Choose an option!", preferredStyle: .ActionSheet)
//Create and add the Cancel action
let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel) { action -> Void in
//Just dismiss the action sheet
}
actionSheetController.addAction(cancelAction)
//Create and add first option action
let takePictureAction: UIAlertAction = UIAlertAction(title: "Take Picture", style: .Default) { action -> Void in
//Code for launching the camera goes here
}
actionSheetController.addAction(takePictureAction)
//Create and add a second option action
let choosePictureAction: UIAlertAction = UIAlertAction(title: "Choose From Camera Roll", style: .Default) { action -> Void in
//Code for picking from camera roll goes here
}
actionSheetController.addAction(choosePictureAction)
//Present the AlertController
self.presentViewController(actionSheetController, animated: true, completion: nil)
}
For AlertView with Text Field
#IBAction func showAlert(sender: AnyObject) {
//Create the AlertController
let actionSheetController: UIAlertController = UIAlertController(title: "Alert", message: "Swiftly Now! Choose an option!", preferredStyle: .Alert)
//Create and add the Cancel action
let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel) { action -> Void in
//Do some stuff
}
actionSheetController.addAction(cancelAction)
//Create and an option action
let nextAction: UIAlertAction = UIAlertAction(title: "Next", style: .Default) { action -> Void in
//Do some other stuff
}
actionSheetController.addAction(nextAction)
//Add a text field
actionSheetController.addTextFieldWithConfigurationHandler { textField -> Void in
//TextField configuration
textField.textColor = UIColor.blueColor()
}
//Present the AlertController
self.presentViewController(actionSheetController, animated: true, completion: nil)
}
Some of the syntax has changed since the original responses. Here is some sample code that alerts the user if they are not signed in to iCloud.
CKContainer.default().accountStatus { (accountStatus, error) in
switch accountStatus {
case .available:
print("iCloud Available")
case .noAccount:
print("No iCloud account")
//simple alert dialog
let alert=UIAlertController(title: "Sign in to iCloud", message: "This application requires iClound. Sign in to your iCloud account to write records. On the Home screen, launch Settings, tap iCloud, and enter your Apple ID. Turn iCloud Drive on. If you don't have an iCloud account, tap Create a new Apple ID", preferredStyle: UIAlertControllerStyle.alert);
//no event handler (just close dialog box)
alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertActionStyle.cancel, handler: nil));
//show it
self.present(alert, animated: true, completion: nil)
case .restricted:
print("iCloud restricted")
case .couldNotDetermine:
print("Unable to determine iCloud status")
}
}

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