#IBAction func unwindOtherVw (seque: UIStoryboardSegue) {
println("the objectfromOtherView is \(objectFromOtherView!)")
}
I'm passing an object (NSManaged) from the other ViewController using prepareForSeque method and exit in the storyboard along with the code above in the destination controller. All is working fine, but how can I add an identifier to the unwind segue so that prepareForSegue could use if seque.indentifier == ______
You should be able to see the unwind segue in the tree view of components on the left. YOU can select it and add an identifier in the attributes inspector.
eg:
Related
I have a Detail View Controller and I want to show the same Detail View Controller but with a different item.
var nexttype : Type!
let nexttypeVC = TypeDetailVC()
#IBAction func buttonTapped(_ sender: UITapGestureRecognizer) {
nexttype = type.Array![0]
nexttypeVC.type = next.type
self.navigationController?.pushViewController(nexttypeVC, animated: true)
}
When I print the name or a identifier of the item I get the correct one, but when I launch the simulator I get error. The values of the labels and everything is nil.
How can I tell the view controller to reload again but with a different item?
Call performSegue(withIdentifier:) rather than pushViewController. You'll need to programmatically register a segue or add one via storyboard. Then use prepare(for segue: sender:) to give the destination ViewController the item you wish. Note that the destination's viewDidLoad() is called after the prepareForSegue.
This is the standard Apple-recommended way to seed the destination ViewController with data it needs prior to its load.
Instead of pushing the same view controller onto the navigation stack. Try to arrange all the logic to update UI elements into a method. Call this method in viewDidLoad(). Calling self.viewDidLoad() is not a good idea.
Use observer pattern and call the method that updates UI elements.
How can I change the identifier name of a specific segue programmatically?
I found this way but didn't work with me:
SWrevealviewcontroller : Switch slideout menu direction from left to right pragmatically
Edit:
I have menu SWreavealviewcontroller and I want it to be from left in case of English language and from right in case of Arabic language.
You can't change segue names programmatically. Because a segue defines a transition between two view controllers in your app’s storyboard file and you can rename it in your storyboard.
You can define more than one segues between your view controllers and call segues programmatically like this:
performSegue(withIdentifier: "yourSegueID", sender: nil)
For your problem:
You can create two segues between your view controllers, and give
two different segue identifier names to them (eg. englishSegue and
arabicSegue).
Create a variable for your segue identifier. (You will use it to
select which of your segue should be triggered.)
Control your language in your view controller (eg. in your
viewDidLoad function or where you should control it)
programmatically and set your language variable as English or Arabic.
After that you can trigger it anywhere you want it. For example in a
button click:
if (yourIdentifier == "English") {
performSegue(withIdentifier: "englishSegue", sender: nil)
} else if (yourIdentifier == "Arabic") {
performSegue(withIdentifier: "arabicSegue", sender: nil)
}
So I have been trying to get a unwind segue to work from last two days. I have tried watching and follow several different tutorials and none was successful. I created the #IBAction override func unwind(for unwindSegue: UIStoryboardSegue, towardsViewController subsequentVC: UIViewController) but this never performs any of the code. I put a simple print and had it print text, it never printed the text. I created that in the first View Controller then in the second View Controller I had a button that I connected to the Exit at the top of the View Controller and selected the unwind action and it never unwinds. What am I doing wrong or missing?
So here is what I have so far I have 2 views: RaceViewController & SingleStatViewController
I will start by selecting specified rows in RaceViewController and they will open SingleStatViewController modally. I have a button in SingleStatViewController called dismissBtn. When I click the button it dismisses SingleStatViewContoller. I just need it to pass some data back to the RaceViewController.
So if the user selects 1 of 3 cells in the table (the rows are Half-Orc, Half-Elf and Human) it will open SingleStatViewController and ask to select 1 stat (these will be of 6 buttons (Str, Dex, Con, Int, Wis, Chr) when they select the one of the buttons it will return the data and update the detailTextLabel.
I select Human then I select Str. When it gets back to RaceViewController and it updates the text in the detailTextLabel to +2 Str.
Right now, this is the code I am using to dismiss. Can I use this to continue or do I actually need to perform the unwind:
#IBAction func dismissbtn(_ sender: Any)
{
dismiss(animated: true, completion: nil)
}
You need to perform unwind and send data as following:
#IBAction func unwindToRaceViewController(sender: UIStoryboardSegue)
{
if let sourceViewController = sender.sourceViewController
as? RaceViewController {
stat = sourceViewController.stat
}
You could refer to this article for unwind segues as alternative to delegate
You could also use delegates to pass data back to the previous controller.
Okay, so you have vc A and vc B, this is what you need to do to use unwind segue:
In vc A, create a segue function eg. #IBAction func unwind(segue: UIStoryboardSegue)
In vc B, write code that call self.performSegueWithIdentifier("unwind", sender: self) (assume that the identifier and the function name is the same - call this in your dismissbtn)
In vc B in storyboard, look on top of it, there will be an yellow button and 2 orange button, hold and drag the yellow button to the Exit orange button, choose the action that you created in vc A, give it an identifier as mentioned
In the unwind func, the rest is the same as normal segue when you pass data forward, just change destination to source and you must present vc B from vc A, else then use delegate
Pardon me for beginner's question.
I know I can switch to another screen (ViewController) like this
self.performSegueWithIdentifier ("SecondViewController", sender: self)
but I can't seem to find where to assign my 2nd screen the id, I just find Storyboard ID, is that it?
I've already tried, only received a crash with the following error:
Receiver () has no segue
with identifier 'SecondViewController'
Any idea? thanks
Segue Identifier is not the same as storyboard ID, storyboard ID used when you want to create a View Controller based on that specific storyboard -and it has to be unique, unlike the segue identifier-.
If you already know how to create a segue, you can skip this part.
Adding a segue between two viewControllers:
From the Interface Builder, press the ctrl and drag between the two View Controllers that you want to link (make sure that you are dragging from the view controller itself, not the its main view). You should see:
Choose the "Show" -for instance-, the output should look like this:
As shown above, the arrow that surrounded by the red rectangle is the segue.
Additional note: if you selected the "Show" option, you have to embed your first view Controller in a Navigation Controller (select your first viewController -> Editor -> Embed In -> Navigation Controller), the output should looks like:
Because the "Show" means pushing into a navigation controller stack.
Assigning an identifier for the segue:
Select the segue, from the attribute inspector you'll see "Identifier" text field, that's it! make sure to insert the exact same name that used in performSegueWithIdentifier.
If you don't know where to find the attribute inspector, it is on the top right looks like:
Furthermore:
For adding multiple segues from one View Controller, follow the same process (ctrl + drag from the first controller to each other View Controller), the output should looks like:
In this case, you might face the issue how to recognize which segue has been performed, overriding prepare(for:sender:) method is the solution, you can make the checking based on the segue identifier property:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "firstSegueIdentifier") {
// ...
} else if (segue.identifier == "secondSegueIdentifier") {
//...
}
}
which would be the name that you have added to the segue in the storyboard.
In your code
self.performSegueWithIdentifier ("SecondViewController", sender: self)
the string "SecondViewController" is looking like storyboard id . At the same place you have to write the segue identifier , not storyboard id .
Follow the Screenshot and assign segue identifier name by clicking on the segue on right top bar field. you can do like this
self.performSegueWithIdentifier ("WriteSegueIdentifierName", sender: self)
Similar to the answers provided, here's what it would look like in Xcode 12:
Select the segue link in Main Storyboard view
Navigate to the Attribute Inspector and add an Identifier (if one does not exist)
Add the Identifier to your code. Done!
When you link a View controller to another View controller in the storyboard, in the link between them you need to assign a segue identifier i.e "SecondViewController" only then your code will work.
Alternatively, you can also show another view controller through storyboard id using self.storyboard.instantiateViewControllerWithIdentifier("//storyboard id of that view controller") and then either use present/show view controller.
You can initiate viewController like this:
let viewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "Login")
self.present(viewController, animated: false, completion: nil)
Show Xcode screenshot
Click on Present Modally segue label... and on the Attributes Inspector input Identifier
I encountered a crash while testing my app. The following image is my storyboard:
I have the code in View Controller:
#IBAction func unwindToHomeScreen(segue:UIStoryboardSegue) {
}
The view of "Add new Item" have a "Cancel" button, I controlled-drag it to the "Exit" icon at the top and link to unwindToHomeScreen, it works fine.
The "Add new Item" has a class AddTableViewController and the code I wrote inside:
#IBAction func save() {
// Execute the unwind segue and go back to the home screen
performSegueWithIdentifier("unwindToHomeScreen", sender: self)
}
I controlled-drag the "Save" button to the func, but the app crash when I click the button
I can use dismissViewControllerAnimated(true, completion: nil) instead, but I just wonder why performSegueWithIdentifier can't work?
I read the code at dropbox.com/s/hpybgg9x67rtqng/foodpinstatictable.zip?dl=0 and try to make one and using performSegueWithIdentifier like this example for practicing, I didn't see the segue identifier at her, what is the difference?
You haven't actually given that segue an identifier. unwindToHomeScreen is a function that you can call; what you're looking for is your segue identifier, which is set in Interface Builder like this:
In this example, I have a button wired to the next view via Interface Builder like you describe ("Interface Builder") and a button that is wired to this IBAction in my view controller ("Programmatically"):
#IBAction func goToNextView(sender: UIButton!) {
self.performSegueWithIdentifier:("go", sender: self)
}
In any case, what you're missing is the actual identifier, which can be set in the attributes of a segue created in Interface Builder.
Swift 4:
Sometimes we must clean the build folder and then try again.
Worked for me after ctrl-dragging the new segue and giving it a name, then using it programatically as:
performSegue(withIdentifier: "goToMyNewViewController" , sender: self)
I found that because I renamed my view controller, I needed to delete and recreate the segue.
A possible issue with iOS 12 and earlier (iOS 13 seems not to suffer from the same issue) might come from the fact that performSegue(withIdentifier:,sender:) is called from the view controller viewdidLoad() callback.
You absolutely must invoke it from the viewDidAppear(_ animated: Bool) callback in order to avoid the question-mentioned crash.
That will certainly save hours of hair-puling…
in my case reorder the Embed in
Tab bar controller
Navigation controller
vc (contains button - tapping button initiates a "show, e.g. push" segue)
Too fix the title in the navigationBar
I had the same issue.
All I did was:
I selected the segue indicator in the storyboard.
Deleted it.
Then created a new segue with the same identifier. Boom, it works.
I had it all wired up correctly. It was just that the viewController I was segueing from, was NOT instantiated from the storyboard. I had it instantiated pragmatically.
I initially had it written as:
let vc = DeviceVC()
Had to change it to:
let sb = UIStoryboard(name: "Main", bundle: Bundle(for: DeviceVC.self))
let vc = sb.instantiateViewController(identifier: "DeviceVC") as! DevieVC
for me --> click on the relation-arrow between view controllers and then select attribute inspector, there is identifier give name and select push class done...