I had a UINavigationController set as initial view controller. The root view controller for that navigation controller shows a menu where users can see product categories (In case that's interesting for anyone :)). The root view controller loads JSON data from an URL, so it takes a little while until the view shows up (which is fine). That data will be use in all the app, so it's an important step.
Well, since the data load takes a while, I added a new UIViewController where I show an image with an UIActivityIndicator. Of course, the data load takes place in this UIViewController now instead of the root view controller.
So, the idea is that after the data is loaded, the root view controller takes the place. To accomplish this I put an "invisible" UIButton on the new view controller and added a UIStoryboardSegue to the navigation controller, so I trigger that segue programmatically after the data is loaded.
After the data gets loaded, the navigation controller actually appears and shows (of course) the root view controller. The problem is when I click any button on the root view controller, the segue performs correctly, but from the "second" view controller (UITableViewController) if I press any cell, it takes me back to the new view controller (the one that shows an image and loads the data). Well not actually any cell, because sometimes it takes me actually forwards to the "third" view controller (also UITableViewController), but the same problem occurs in this view controller. If I click the back button on the navigation bar in any view controller, it takes me back to the new view controller and not really back in the navigation stack.
Here is ViewDidLoad:
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
load.loadAllProducts()
load.loadCategories()
self.performSegueWithIdentifier("mainStoryboardSegue", sender: self)
}
And PrepareForSegue:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let destination = segue.destinationViewController as? UINavigationController
let homeViewController = destination!.viewControllers.first as? HomeViewController
homeViewController!.categories = load.categories
homeViewController!.products = load.products
}
I really appreciate any help, thanks a lot!
The solution that worked for me was to change the current active view controller by setting this:
let newController = storyboard.instantiateViewControllerWithIdentifier(storyboardId) as? UINavigationController
UIApplication.sharedApplication().keyWindow!.rootViewController = newController
Related
I want to make an Flashcards App and the behaviour is that on the CoursesVC, the user can add courses and click on them. Then he gets the list with flashcards. There he can add more flashcards. The storage is managed by CoreData. When its clicked on the cell, I pass the data to the flashcards list with prepareForSegue. To add the flashcard, I had the same idea in mind, but it was not possible because the variable from the second view controller wasn't initialised, when prepareForSegue was created. Question: How can I pass a NSManagedObject from the first ViewController to the third ViewController in an appropriate way? (ugly way would be to let the view render before creating prepareForSegue)
The difference to questions like "how to pass data between ViewControllers" is that I have three ViewControllers. It won't work with using prepareForSegue at the first and at the second view controller, because when the prepareForSegue is created, the variable in the second VC is not defined yet, because the view is not initialised yet! Keep in mind that the segue from the second to the third view controller is "Present Modally" as "Page Sheet"!
This is the solution basically: Swift : prepareForSegue with navigation controller
The problem was that the third view controller is embedded as a navigation controller. That is the reason why the prepareForSegue is different.
Solution is to use following prepareForSegue in the second VC:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let navigationVC = segue.destination as? UINavigationController, let myViewController = navigationVC.topViewController as? DViewController {
myViewController.currentCourse = self.currentCourse
}
}
I have a view controller as my initial view controller. there's a button in it(GO button) which when the user taps, it should go to another view controller(let's call it Destination view controller with label 'This is where i wanna go'). Meanwhile i want to pass it through a Tabbar controller. The reason is i want to have tabbar in my navigation stack.
I wish to go directly to the Destination view controller while pressing go button but it should show the tab bar items at the bottom.
So for achieving this in FirstViewController didLoadMethod I checked a bool value and pushed the view controller to the Destination view controller. I achieved the result I.e when pressing the Go button it goes to the Destination view controller and has tab bar items at it's bottom.
But the problem since it passes through the Tabbarcontroller the FirstViewController is shown for some seconds and then it pushes to the Destination view controller. I wish to hide FirstViewController while this transition takes place.
How to achieve this?
Picture shows what i want. what can I do to hide firstviewcontroller while having it in navigation stack?
I think this can be done in a simple way -
In the first viewController of the tab bar has a viewDidLoad() function or you can use loadView() which is called before the viewDidLoad() function. Push to the next viewController in the function.
Put your push navigation code in one of those functions
*You cant see the current view coltroller, it will push the screen to your required viewcontroller before loading the tab bar initial view contoller.
Hope it will work for you.
or >>>> you can check it out
let storyboard = UIStoryboard(name: "your_storyBoard_name", bundle: nil)
let viewController1 = storyboard.instantiateViewController(withIdentifier: "firstViewController")
let viewController2 = storyboard.instantiateViewController(withIdentifier: "secondViewcontroller")
let controllers = [viewController1, viewController2]
self.navigationController!.setViewControllers(self.navigationController!.viewControllers + controllers, animated: true)
The effect you're trying to produce is hard to do in a storyboard. Programmatically you would simply create the Tabbar Controller (with its children) and the "This is where I want to go" Controller, and then ask the navigation controller to show both at the same time.
For example, after "Go" is tapped, this is the code I would run inside your first view controller:
let tabBarController = UITabBarController()
let finalDestination = UIViewController()
var viewControllers = self.navigationController?.viewControllers ?? []
viewControllers.append(tabBarController)
viewControllers.append(finalDestination)
self.navigationController?.setViewControllers(viewControllers, animated: true)
Given the structure you shown, where the view controller A is the root view controller of the TabBar, you should push the second view controller B on the navigation stack inside either willAppear or didLoad of view controller A, according to your personal business logic (flag, conditions, etc.).
The trick here is to use either pushViewController or setViewControllers with animated: false so that the navigation stack will be set immediately during willAppear/didLoad and it won't show the push animation of B over A. This way, at onDidAppear the layout will be already fully rendered in it's final state: with B at the top of the navigation stack and no animations in progress.
My target include a lot view need to present different view modally base on each user action. Here what I want to do to get cleaner view hierarchy and better user experience.
Root View Controller present First View Controller modally
When I clicked button on the First View Controller, then the Second View Controller appear modally over it.
As soon as the Second View Controller did appear, I want to dismiss or remove the first one from view hierarchy.
Can I do that? If so, how should i do it?
If not, what is the right way to solve this out cause I will present many modally presented view controllers over each view. I think even if I want to dismiss current view, the previous one will still remain appear when current one dismiss.
UPDATE :
VC1 (Root) > VC 2 (which was present modally) > VC 3 (which was
present modally over VC 2)
When i dismiss VC3, the VC2 is still on view memory. So, I don't want to appear VC2 as soon as I dismiss VC3 and instead I want to see VC1 by removing or dismissing VC2 from view hierarchy.
WANT : At the image, when I dismiss the blue,I don't want see the pink in my view memory and I want to remove it as soon as the blue one appear.
That's what i want to do.
Any Help?Thanks.
So, let's assume that you have a storyboard similar to:
What should happens is:
Presenting the the second ViewController (from the first ViewController).
Presenting the the third ViewController (from the second ViewController).
dismissing to the first ViewController (from the third ViewController).
In the third ViewController button's action:
#IBAction func tapped(_ sender: Any) {
presentingViewController?.presentingViewController?.dismiss(animated: true, completion: nil)
}
As you can see, by accessing the presentingViewController of the current ViewController, you can dismiss the previous hierarchy of the view controllers:
The view controller that presented this view controller.
By implementing presentingViewController?.presentingViewController? that means that: the presented of the presented current ViewController :)
It might seem a little bit confusing, but it is pretty simple.
So the output should be like (I added background colors to the viewControllers -as vc1: orange, vc2: black and vc3: light orange- to make it appears clearly):
EDIT:
If you are asking to remove the ViewController(s) in the middle (which in this example the second ViewController), dismiss(animated:completion:) does this automatically:
If you present several view controllers in succession, thus building a
stack of presented view controllers, calling this method on a view
controller lower in the stack dismisses its immediate child view
controller and all view controllers above that child on the stack.
When this happens, only the top-most view is dismissed in an animated
fashion; any intermediate view controllers are simply removed from the
stack. The top-most view is dismissed using its modal transition
style, which may differ from the styles used by other view controllers
lower in the stack.
Referring to what are you asking:
I think even if I want to dismiss current view, the previous one will
still remain appear when current one dismiss.
I think that appears clearly on the UI (and I find it ok), but as mentioned in the dismiss documentation discussion, both the third and the second will be removed from the stack. That's the right way.
Here is my opinion in different perspective,
Root View Controller present Second View Controller
Add FirstView onto Second View
Dismiss FirstView Controller when button pressed.
Second View Controller,
class ViewController: UIViewController, FirstViewControllerProtocol {
weak var firstViewController: FirstViewController?
override func viewDidLoad() {
super.viewDidLoad()
print("Not initiated: \(firstViewController)")
firstViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "FirstViewController") as? FirstViewController
addChildViewController(firstVC!)
firstViewController?.delegate = self
view.addSubview((firstViewController?.view)!)
print("Initiated: \(firstViewController)")
}
func dismiss() {
firstViewController?.view.removeFromSuperview()
firstViewController?.removeFromParentViewController()
}
}
FirstViewController,
protocol FirstViewControllerProtocol {
// Use protocol/delegate to communicate within two view controllers
func dismiss()
}
class FirstViewController: UIViewController {
var delegate: FirstViewControllerProtocol?
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func dismiss(_ sender: Any) {
delegate?.dismiss()
}
deinit {
print("BYE")
}
}
What you want is an "unwind segue":
https://developer.apple.com/library/archive/featuredarticles/ViewControllerPGforiPhoneOS/UsingSegues.html#//apple_ref/doc/uid/TP40007457-CH15-SW8
https://developer.apple.com/library/archive/technotes/tn2298/_index.html
It allows you to dismiss multiple view controllers at the same time, without having to know how many there are in the stack.
In VC1 you would implement an IBAction called (for instance) unwindToRoot. Then in the storyboard for VC3, you wire up your Done button to the Exit object and choose the unwindToRoot action.
When that button is pressed, the system will dismiss all the view controllers it needs to bring you back to VC1.
This is better than calling presentingViewController?.presentingViewController?.dismiss(), because VC3 doesn't need to know anything about the view controller hierarchy underneath it.
I had to add a navigation controller to my app so that I could use the left drawer menu (using SWRevealViewController) but its messing up my segues. My initial design had a login screen that segued to one of 4 different scenes depending on an a status indicator.
Now that I had to add a navigation controller it looks like i'll have to take the user sequentially through through each screen in the stack until they reach the relevant one. Is there a way I can jump past the first screen or 2? Or a way to not show them as I navigate through.
I tried putting the performSegue in the viewWillLoad delegate method but the screen still loads before segueing to the next scene.
Add Storyboard IDs to all View/Navigation Controllers that will eventually be pushed:
Now to push the desired view it depends whether your current View Controller stands: within or outside the Navigation Controller's stack:
If your VC is already in the Navigation Controller stack
From your current ViewController push the desired view:
if let myViewController = self.storyboard?.instantiateViewControllerWithIdentifier("myViewController") as? MyViewControllerClassName {
self.navigationController?.pushViewController(myViewController, animated: true)
}
Note: as? MyViewControllerClassName is only required if your View Controller's class is not the default UIViewController but a custom one that extends it instead.
If your VC is NOT in the Navigation Controller stack
Same principle apply, only this time you need to push the Navigation Controller itself before pushing the desired View Controller:
if let newNavController = self.storyboard?.instantiateViewControllerWithIdentifier("myNavigationController") as? UINavigationController {
self.view.window?.rootViewController = newNavController
// Now push the desired VC as the example above, only this time your reference to your nav controller is different
if let myViewController = self.storyboard?.instantiateViewControllerWithIdentifier("myViewController") as? MyViewControllerClassName {
newNavController.pushViewController(myViewController, animated: true)
}
}
Im trying to get two navigation controller on the same stack, and pass data between them , the best way to explain this is by the image below .
first nav controller(the one thats furthest to the left ) is connected to a TabBarController .
When passing data from the TEST tableViewController to the 2nd tableViewController (subDuaList) , i get an error in my code in the prepareForSegue method ...
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
var subDua:subDuaList = segue.destinationViewController as subDuaList //ERROR OCCURS HERE
var Index = tableView!.indexPathForSelectedRow()?.row
var duaIndex = 130 - Index!
var selectedDua = self.packagedChapter[duaIndex]
println(selectedDua.title)
subDua.duaArray = selectedDua.dataArray
subDua.rowPressed = Index
}
Reason for embedding the second tableViewController in a Navigation controller is so that I can add a bar button item to the nav bar.
EDIT
As #Shim commented right, my answer just explains the reason for the error output, but does not tell the things I already said in my comment on your question:
It is not allowed to push a UINavigationController on an existing navigation stack. Therefore you should remove the second navigation controller and just add a UIBarButtonItem to the navigationItem of your subDuaList view controller.
The reason for your error is, that the segue.destinationViewController is the second UINavigationController and not the subDuaList view controller.
If it was allowed, you could have repaired your code as follows by replacing:
var subDua:subDuaList = segue.destinationViewController as subDuaList //ERROR OCCURS HERE
with
var navCtrl:UINavigationController = segue.destinationViewController as UINavigationController
var subDua:subDuaList = navCtrl.childViewControllers[0] as subDuaList
You don't need a new navigation controller to add a bar button item. You can add a bar button item in the storyboard by dragging it onto the navigation bar (if the view controller is in a navigation stack and you don't see one, check the simulated metrics in the inspector), or you can add it in code like so:
self.navigationItem.rightBarButtonItem = myBarButtonItem;