I use this simple code to segue:
self.performSegue(withIdentifier: "showSeqTwo", sender: self)
After this segue, I need a timer in the controller to launch automatically. The problem is that normally the timer is supposed to be launched by pressing a play button, and then paused and relaunched at will. The user can also swipe to this controller, in which case the timer should not be triggered. Can I send some kind of a signal with this particular segue to programmatically "push" the button and launch the timer?
You can send a variable that is read in the viewDidLoad() function of the second viewController, and determine if the play button should activate.
Add a function to the bottom of your first viewController like this:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showSeqTwo" {
let destination = segue.destination as! NameOfSecondViewControllerClass
destination.segueFlag = 1
}
}
Inside the second viewController, add the following variable into the class:
var segueFlag = 0
Inside the viewDidLoad() of the second viewController, add the following code
if segueFlag == 1 {
// Add function to start play button here
}
Related
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
super.prepare(for: segue, sender: sender)
self.delegate = segue.destination as? MenuViewController
print("check_1", self.delegate)
}
#IBAction func openMenu(_ sender: Any) {
performSegue(withIdentifier: "openMenu", sender: sender)
print("check_2", self.delegate)
}
My main ViewController updates values while MenuViewController displays these values. Each time ViewController values are updated, it calls self.delegate.updateValues in MenuViewController. I transition between the two ViewControllers through buttons.
My problem is that it seems like the MenuViewController displayed is a different object than the one stored in self.delegate inside ViewController. Printing the check statements:
check_1 Optional(<Menu.MenuViewController: 0x10161ca10>)
check_2 Optional(<Menu.MenuViewController: 0x10161ca10>)
check_1 Optional(<Menu.MenuViewController: 0x10161dd10>)
May I ask how do I make sure only one instance of MenuViewController is created and stored in self.delegate?
When you add a segue to a storyboard, if you hook up the segue to a specific button/IBAction, you don't need to call performSegue manually, it will be automatically called for you.
You have 2 segues executed, since both the storyboard executes the segue and then you also do it from code by calling performSegue.
performSegue should only be used when your segue isn't directly hooked up to a UI event or if you need to conditionally perform a segue - such as when you have a login button, where depending on the network response, you might execute an error or a login segue.
I have more than 20+ buttons in my application. For these buttons if I click twice it performSegue twice and opens the viewcontroller twice, throughout my application in swift iOS?
self.performSegue(withIdentifier: "toViewController", sender: nil)
You can attach a tag to each button and define an array of segues
self.performSegue(withIdentifier:segues[sender.tag], sender: nil)
or simply make the button the source of the segue , if you're not willing to override prepareForSegue
You could declare a property
var isSegueEnabled = true
Then implement the method to control whether the segue should be performed
func shouldPerformSegue(withIdentifier identifier: String, sender: Any?) -> Bool {
return isSegueEnabled
}
In prepare(for segue set the property to false
isSegueEnabled = false
At some point after the presented view controller has been dismissed set isSegueEnabled back to true
my problem is that when i switch to an another ViewController, my variables of the previous VC call are reset so i can't do what i want after
#IBAction func BackBtn(_ sender: Any) {
self.nbrQst = 10
self.Switch1A = 2
performSegue(withIdentifier: "Numero", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "Numero" {
let vc = segue.destination as! ViewController
vc.nbrQt = nbrQst
}
if segue.identifier == "Numero" {
let vcNv = segue.destination as! ViewController
vcNv.Switch1 = Switch1A
}
}
below the way that i send information from my Lvl1 file to the lvl selector file to add a if else for unblocks the lvl
#IBAction func BackBtn(_ sender: Any) {
self.nbrQst = 10
self.Switch1A = 2
performSegue(withIdentifier: "Numero", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let vc = segue.destination as! ViewController
vc.nbrQt = nbrQst
vc.Switch1 += 2
}
that's the second ViewController who send the number to the first one, and i want that the first one remember the number and add them up each time I press the button that sends the numbers
Let's call "Selector VC" the main VC.
The reason why those numbers reset in main VC is that when you press the "BackBtn", you're not actually going back to main VC, you're creating a new main VC and going there (because you did performSegue(withIdentifier: "Numero", sender: self) in BackBtn function, performSegue always takes you to a new VC rather than taking you back). The new main VC has all those fields starting from an initial number (I assume initially they're zero).
What you want to do is to go BACK, not forward. Depending on how you went to the level VC from main VC, you have different ways of going back to main VC.
If you're pushing everything onto a navigation controller, then you can go back by:
self.navigationController?.popToRootViewController(animated: true)
If you're presenting everything modally, you can go back by
self.dismiss(animated: true, completion: nil)
You said, you want to update the value in main VC so that you can block/unblock next level. A very standard way to achieve this is via delegate, please Google this ("delegates in Swift") and follow their tutorials there.
I strongly recommend that you take an online course on swift development before you go ahead and develop your own app, because you could potentially do a lot of things wrong and waste a lot of your time trying to get an answer from Stack Overflow.
I have setting like this:
First controller reads data and sets in Second Controller.
Second Controller has a button that executes push segue to Third Controller with a countdown.
After countdown I want to go back from third controller to second that should still have data. Is there any way to achieve this?
Also I am using Storyboards.
I send data to Second Controller in prepare func. Second to Third controller change is connected directly to button in Storyboards.
override func prepare(for segue: UIStoryboardSegue, sender: AnyObject?) {
let controller = segue.destination as! QuestionViewController
controller.questionIDs = sender as! [Int]
}
To come back from Third to Second controller I use this code from Third controller:
self.performSegue(withIdentifier: "nobodyAnsweredSegue", sender: self)
Change this:
self.performSegue(withIdentifier: "nobodyAnsweredSegue", sender: self)
To this:
self.navigationController?.popViewControllerAnimated(true)
I have a segue running form a Collection View (wrapped in a view controller) in to a another view controller, how ever the function never gets called:
func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
println(segue.identifier)
println(sender)
println("SEGUE SELECTED: \(segue.identifier)")
if(segue.identifier == "segueToDetailView") {
let cell = sender as CollectionViewCell;
}
}
Have placed a breakpoint at start of function but never reached.
Any input appreciated.
I will suggest not to create segue(s) from cell or any object(like button).
Create segue from one ViewController to OtherViewController with unique identifier.
And then call the performSegueWithIdentifier yourself using the identifier.