I want to use a push segue to edit an "entry" that is otherwise added via a present modally segue. It doesn't dismiss using the normal dismissViewControllerAnimated method when pressing cancel. Because of this I had to combine the popViewControllerAnimated method at the same time, so that depending on whether they click cancel when editing an entry or adding it, it will try both.
Both are done via NSNotifcation, because of objects I need to carry back from the last viewcontroller to the first:
func cancel(notification: NSNotification){
println("Cancel Executed")
let userInfo:Dictionary<String,EntryItem!> = notification.userInfo as Dictionary<String,EntryItem!>
entry = userInfo["Object"]
tableView.reloadData()
self.navigationController?.popViewControllerAnimated(true)
dismissViewControllerAnimated(true, completion: nil)
dataModel.saveEntries()
}
The problem with this is that if I go through the segues to arrive at the third view controller (in a string of 5), I cancel, and it goes back to the entries screen, but a messed up looking navigation bar takes the place of what is supposed to be there. There's no title showing either. It has a cancel button which causes a crash if you press it.
Here's what it's supposed to look like:
Here's what the popViewControllerAnimated does to it.
Related
I'am new to ios. I have several view controllers and I want back button to get user to level up controller. Example.
But if user comes from gameOver view, back button sent him back to gameOver and I don't want such behavior (I want user to be sent at second level (games level) controller as shown). On android I could set the pop behavior for the navigation actions with mouse very easily.
What is the correct way to do the same in ios? Or I have to create the custom back button and do everything manually?
Using Swift this can be achieved using below code:
func popToViewController(_ specificViewController: Swift.AnyClass) {
let viewControllers = self.navigationController!.viewControllers
for eachViewController in viewControllers {
if eachViewController.isKind(of: specificViewController) {
self.navigationController!.popToViewController(eachViewController, animated: true)
break;
}
}
}
Usage:
self.popToViewController(gameLevelViewController.self)
What I want is to close a viewController after performing a segue so that the back button of the navigation controller on the new view doesn't go back to the view that I just closed, but it goes to the view that precedes it in the storyboard like it is the first time that it is loaded.
I already tried stuff like dismiss and so but it doesn't really work for me as it only closes the view in which the button that I pressed for performing the function is located :
#objc func goToList(){
self.dismiss(animated: true, completion: nil)
performSegue(withIdentifier: "goToList", sender: nil)
}
The navigation controller maintains a stack (array) of ViewControllers that have been opened (pushed). It also has the ability to pop these ViewControllers off the stack until it gets to a specific one.
For example, if you wished to return to a previous view controller of type MyInitialVC then you'd want to search through the stack until you found that type of VC, and then pop to it:
let targetVC = navigationController?.viewControllers.first(where: {$0 is MyInitialVC})
if let targetVC = targetVC {
navigationController?.popToViewController(targetVC, animated: true)
}
NB. written from memory without XCode, so you may need to correct minor typos
You can use unwind segue to get back to each viewController that you want.
Read more here:
Unwind Segues Step-by-Step (and 4 Reasons to Use Them)
I'm creating a Popup error message for my own app. I have followed a tutorial in Youtube. As my app is a tab bar app when Popup, comes up and a user presses another tab and then get back to that specific tab the background is changed !!!! any Idea what is happening here?
1. This is when the popUp comes up
2.This one is when has change the tab and then came back to that specific tab
3.This is the last state when the user close the popup after they changed the tab
none of these bugs happens if the user closes the pop up at the beginning!
let next = self.storyboard?.instantiateViewController(withIdentifier: "ErrorVC")
self.present(next!, animated: true, completion: nil)
and this is the code I have used in my page to show the pop when it meets the conditions !!!
I have 2 viewController and second one is the pop up.
Set definesPresentationContext property to true of UIViewController in first viewController where you're displaying pop-view
override func viewDidLoad() {
super.viewDidLoad()
definesPresentationContext = true
}
I have this code in one of my IBAction (when a button is pressed), which is supposed to bring up a new view controller.
let addAlertVC = self.storyboard?.instantiateViewController(withIdentifier: "addAlert")
self.present(addAlertVC!, animated: false, completion: nil)
However, when I run the app and press the button that's supposed to take me to the new viewcontroller, but then I'm stuck with the original viewcontroller. I have put a print statement in the viewDidAppear function in the new view controller, and it is printing out whenever I press the button, so the new controller is definitely appearing. I have not dismissed the new controller anywhere in my app.
I have used the same code in other parts of my app, so I'm extremely confused as to why it's not working this time.
Any help would be greatly appreciated.
EDIT: I fixed my code. It turns out it wasn't how I was calling the view controller that was wrong, it was my button. Once I deleted and re-added the button, my code now works.
There is a good chance that your view controller is deallocated after you present it.
Try to declare your view controller outside of the function, in your controller. Something like:
class ViewController{
var addAlertVC:UIViewController?
...
func someFunction(){
addAlertVC = self.storyboard?.instantiateViewController(withIdentifier: "addAlert")
self.present(addAlertVC!, animated: false, completion: nil)
}
}
I have a settings screen, in that I have a table cell. By clicking on that I take to another screen where user can choose an option and I want it back in the previous view controller when back button is pressed.
I can put a custom bar button item, but I want to return to the parent view controller using the back button in the navigation bar rather than with a custom button on the view.
I don't seem to be able to override the navigation back button to point it down to my unwind segue action and since the back button doesn't appear on the storyboard, I cant drag the green Exit button to it
Is it possible to unwind a push segue with the back button?
Here's my solution, based on Objective-C code from Blankarsch to this StackOverflow question: How to trap the back button event
Put this code inside the View Controller you want to trap the Back button call from:
override func didMoveToParentViewController(parent: UIViewController?) {
if (!(parent?.isEqual(self.parentViewController) ?? false)) {
println("Back Button Pressed!")
}
}
Inside of the if block, handle whatever you need to pass back. You'll also need to have a reference back to calling view controller as at this point most likely both parent and self.parentViewController are nil, so you can't navigate the View Controller tree.
Also, you might be able to get away with simply checking parent for nil as I haven't found a case where pressing the back button didn't result in parent being nil. So something like this is a bit more concise:
override func didMoveToParentViewController(parent: UIViewController?) {
if (parent == nil) {
println("Back Button Pressed!")
}
}
But I can't guarantee that will work every time.
Do the following in the view controller that has the back button
Swift 3
override func didMove(toParentViewController parent: UIViewController?) {
if !(parent?.isEqual(self.parent) ?? false) {
print("Parent view loaded")
}
super.didMove(toParentViewController: parent)
}
I tried the same and it seems that you cannot catch the standard back button's action so the solution will be to use a custom button and bind it to a segue which leads back to the previous page.
You could use some sort of delegation as you did or use a custom back button and an unwind segue.
Better even, you could handle passing data between your view controllers using a mediator:
http://cocoapatterns.com/passing-data-between-view-controllers/