I am dismissing a popover view controller programmatically. How can i detect that in my first view controller? Is there a way to send values from the popover to the first one?
Note: popoverPresentationControllerDidDismissPopover does not work when dismissed programmatically.
Any proposition?
this is my code in the main view controller:
let addFriendsPopoverViewController = storyboard?.instantiateViewControllerWithIdentifier("HomeEmotionPopOver") as! EmotionPopOverViewController
addFriendsPopoverViewController.modalInPopover = true
addFriendsPopoverViewController.modalPresentationStyle = UIModalPresentationStyle.Popover
addFriendsPopoverViewController.preferredContentSize = CGSizeMake(100, 100)
let popoverMenuViewController = addFriendsPopoverViewController.popoverPresentationController
popoverMenuViewController!.permittedArrowDirections = .Any
popoverMenuViewController!.delegate = self
popoverMenuViewController!.sourceView = self.view
let height = (self.tableView.rowHeight - HeartAttributes.heartSize / 2.0 - 10) + (self.tableView.rowHeight * CGFloat((sender.view?.tag)!)) - 50
popoverMenuViewController!.sourceRect = CGRect(
x: 30,
y: height,
width: 1,
height: 1)
presentViewController(
addFriendsPopoverViewController,
animated: true,
completion: nil)
and in the popover view controller, i'm dismissing it from a button IBAction:
#IBAction func dismissPop(sender: AnyObject) {
self.dismissViewControllerAnimated(true, completion: nil)
}
The way you have worded your question is that you are looking for a function on the main view controller that is called when a popover is dismissed.
This technically happens with viewDidAppear(animated:). However, it isn't a full proof solution. If your popover doesn't cover the full screen context, this function wont fire, so it is an unreliable solution.
Really what you want is to invoke a function from the popover alerting the main view controller that it has finished/dismissed. This is easily done with a delegate protocol
protocol PopoverDelegate {
func popoverDismissed()
}
class PopoverViewController {
weak var delegate: PopoverDelegate?
//Your Popover View Controller Code
}
Add the protocol conformance to your main view controller
class MainViewController: UIViewController, PopoverDelegate {
//Main View Controller code
}
Then you need to set the delegate to for the popover to be the main view controller.
let addFriendsPopoverViewController = storyboard?.instantiateViewControllerWithIdentifier("HomeEmotionPopOver") as! EmotionPopOverViewController
addFriendsPopoverViewController.delegate = self
//The rest of your code
Finally, call this delegate function from your popover view controller when you dismiss.
#IBAction func dismissPop(sender: AnyObject) {
dismissViewControllerAnimated(true, completion: nil)
delegate?.popoverDismissed()
}
And in your main view controller, implement the delegate method
func popoverDismissed() {
//Any code to run when popover is dismissed
}
The trick is to dismiss the segue yourself but make it seem that the user initiated it so it can be detected by the delegate method popoverPresentationControllerDidDismissPopover().
I did it by adding a completion closure to the presentingViewController dismiss() function and directly invoked the routine.
if let pvc = self.presentingViewController {
var didDismiss : ((UIPopoverPresentationController) -> Void)? = nil
if let delegate = popoverPresentationController?.delegate {
// check it is okay to dismiss the popover
let okayToDismiss = delegate.popoverPresentationControllerShouldDismissPopover?(popoverPresentationController!) ?? true
if okayToDismiss {
// create completion closure
didDismiss = delegate.popoverPresentationControllerDidDismissPopover
}
}
// use local var to avoid memory leaks
let ppc = popoverPresentationController
// dismiss popover with completion closure
pvc.dismiss(animated: true) {
didDismiss?(ppc!)
}
}
It is working fine for me.
Related
I'm a beginner. I am doing a popover when a button is pressed which then instantiates another view controller where the user can select from 5 choices. I want to be able to save the sender.tag of the button from the first view controller (where code snippet below came from) and pass it to the second where I can save them together to Parse. I'm not using a segue so I can't pass it that way. Thanks in advance!
func showPopover(sender: UIButton) {
let vc = self.storyboard?.instantiateViewControllerWithIdentifier("SelectionViewController")
vc!.modalPresentationStyle = .Popover
vc!.preferredContentSize = CGSizeMake(150, 30)
if let presentationController = vc!.popoverPresentationController {
presentationController.delegate = self
presentationController.permittedArrowDirections = .Up
presentationController.sourceView = self.view
presentationController.sourceRect = sender.frame
self.presentViewController(vc!, animated: true, completion: nil)
}
}
The easiest way would be to declare a variable var myVariable = Int() outside of either view controller class. Then, inside of your main VC and before you instantiate the popover, save the tag to the variable. You'll be able to use it inside the popover.
You could just use a segue (why aren't you?)
You put a property for the tag in the popover and set it in the first view controller, inside
func prepareForSegue(_ segue: NSStoryboardSegue, sender sender: AnyObject?).
To perform the segue, you just use
func performSegueWithIdentifier(_ identifier: String, sender sender: AnyObject?)
, inside your function
func showPopover(sender: UIButton)
If you don't want to use a segue you can simply cast the controller you get from instantiateViewControllerWithIdentifier() to your subclass.
Swift 2.0
func showPopover(sender: UIButton) {
guard let vc = self.storyboard?.instantiateViewControllerWithIdentifier("SelectionViewController") as? MYViewController
} else {
print("This is not the view controller you were looking for..."
return
}
vc.myVariableName = sender.tag
...
}
On my iPad app, I have a UIViewController with a button that open a modalView.
#IBAction func showPostCommentViewController(sender: AnyObject){
let modalView = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("PostCommentViewController") as! PostCommentViewController
modalView.modalTransitionStyle = UIModalTransitionStyle.CoverVertical
modalView.modalPresentationStyle = UIModalPresentationStyle.FormSheet
modalView.delegate=self
self.presentViewController(modalView, animated: true, completion: nil)
}
When I close the modalView with dismissViewControllerAnimated, I would like "refresh" my view controller (because I added new content). But as the modal view is a "formsheet" style, viewDidAppear or viewWillAppear aren't called.
I tried to use setNeedsDisplay, but it doesn't work.
I don't know how to do.
This would be a perfect use case for the delegate pattern.
1) define a protocol within PostCommentViewController.
protocol PostCommentVCInformationDelegate {
func hasDismissedPostCommentViewController(controller:PostCommentViewController)
}
2) Set a delegate variable within PostCommentViewController
var delegate: PostCommentVCInformationDelegate?
3) When you dismiss PostCommentViewController, you will call delegate?.hasDismissedPostCommentViewController(self)
This will send information back to the presenting VC.
4) Now we have our presenting View Controller conform to this protocol.
class ViewController: UIViewController, PostCommentVCInformationDelegate
5) When presenting the modal View:
modalView.delegate = self
6) Finally, we implement:
func hasDismissedPostCommentViewController(controller: PostCommentViewController) {
//Update
}
I'm trying to add a simple popoverController to my iphone app, and I'm currently struggling with the classic "blank screen" which covers everything when I tap the button.
My code looks like this:
#IBAction func sendTapped(sender: UIBarButtonItem) {
var popView = PopViewController(nibName: "PopView", bundle: nil)
var popController = UIPopoverController(contentViewController: popView)
popController.popoverContentSize = CGSize(width: 3, height: 3)
popController.presentPopoverFromBarButtonItem(sendTappedOutl, permittedArrowDirections: UIPopoverArrowDirection.Up, animated: true)
func adaptivePresentationStyleForPresentationController(controller: UIPresentationController!) -> UIModalPresentationStyle {
// Return no adaptive presentation style, use default presentation behaviour
return .None
}
}
The adaptivePresentationStyleForPresentationController-function was just something I added because I read somewhere that this is what you need to implement to get this function on the iphone. But still: there is still a blank image covering the whole screen, and I do not know how to fix it.
Any suggestions would be appreciated.
The solution I implemented for this is based on an example presented in the 2014 WWDC session View Controller Advancements in iOS 8 (see the slide notes). Note that you do have to implement the adaptivePresentationStyleForPresentationController function as a part of the UIPopoverPresentationControllerDelegate, but that function should be outside of your sendTapped function in your main view controller, and you must specify UIPopoverPresentationControllerDelegate in your class declaration line in that file to make sure that your code modifies that behaviour. I also took the liberty to separate out the logic to present a view controller in a popover into its own function and added a check to make sure the function does not present the request view controller if it is already presented in the current context.
So, your solution could look something like this:
// ViewController must implement UIPopoverPresentationControllerDelegate
class TheViewController: UIViewController, UIPopoverPresentationControllerDelegate {
// ...
// The contents of TheViewController class
// ...
#IBAction func sendTapped(sender: UIBarButtonItem) {
let popView = PopViewController(nibName: "PopView", bundle: nil)
self.presentViewControllerAsPopover(popView, barButtonItem: sender)
}
func presentViewControllerAsPopover(viewController: UIViewController, barButtonItem: UIBarButtonItem) {
if let presentedVC = self.presentedViewController {
if presentedVC.nibName == viewController.nibName {
// The view is already being presented
return
}
}
// Specify presentation style first (makes the popoverPresentationController property available)
viewController.modalPresentationStyle = .Popover
let viewPresentationController = viewController.popoverPresentationController?
if let presentationController = viewPresentationController {
presentationController.delegate = self
presentationController.barButtonItem = barButtonItem
presentationController.permittedArrowDirections = .Up
}
viewController.preferredContentSize = CGSize(width: 30, height: 30)
self.presentViewController(viewController, animated: true, completion: nil)
}
func adaptivePresentationStyleForPresentationController(controller: UIPresentationController) -> UIModalPresentationStyle {
return .None
}
}
Real world implementation
I implemented this approach for input validation on a sign up form in an in-progress app that I host on Github. I implemented it as extensions to UIVIewController in UIViewController+Extensions.swift. You can see it in use in the validation functions in AuthViewController.swift. The presentAlertPopover method takes a string and uses it to set the value of a UILabel in a GenericAlertViewController that I have set up (makes it easy to have dynamic text popovers). But the actual popover magic all happens in the presentViewControllerAsPopover method, which takes two parameters: the UIViewController instance to be presented, and a UIView object to use as the anchor from which to present the popover. The arrow direction is hardcoded as UIPopoverArrowDirection.Up, but that wouldn’t be hard to change.
I have found few posts for this problem but none of them solved my issue.
Say like I've..
ViewControllerA
ViewControllerB
I tried to add ViewControllerB as a subview in ViewControllerA but, it's throwing an error like "fatal error: unexpectedly found nil while unwrapping an Optional value".
Below is the code...
ViewControllerA
var testVC: ViewControllerB = ViewControllerB();
override func viewDidLoad()
{
super.viewDidLoad()
self.testVC.view.frame = CGRectMake(0, 0, 350, 450);
self.view.addSubview(testVC.view);
// Do any additional setup after loading the view.
}
ViewControllerB is just a simple screen with a label in it.
ViewControllerB
#IBOutlet weak var test: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
test.text = "Success" // Throws ERROR here "fatal error: unexpectedly found nil while unwrapping an Optional value"
}
EDIT
With the suggested solution from the user answers, ViewControllerB in ViewControllerA is going off the screen. Grey border is the frame I have created for the subview.
A couple of observations:
When you instantiate the second view controller, you are calling ViewControllerB(). If that view controller programmatically creates its view (which is unusual) that would be fine. But the presence of the IBOutlet suggests that this second view controller's scene was defined in Interface Builder, but by calling ViewControllerB(), you are not giving the storyboard a chance to instantiate that scene and hook up all the outlets. Thus the implicitly unwrapped UILabel is nil, resulting in your error message.
Instead, you want to give your destination view controller a "storyboard id" in Interface Builder and then you can use instantiateViewController(withIdentifier:) to instantiate it (and hook up all of the IB outlets). In Swift 3:
let controller = storyboard!.instantiateViewController(withIdentifier: "scene storyboard id")
You can now access this controller's view.
But if you really want to do addSubview (i.e. you're not transitioning to the next scene), then you are engaging in a practice called "view controller containment". You do not just want to simply addSubview. You want to do some additional container view controller calls, e.g.:
let controller = storyboard!.instantiateViewController(withIdentifier: "scene storyboard id")
addChild(controller)
controller.view.frame = ... // or, better, turn off `translatesAutoresizingMaskIntoConstraints` and then define constraints for this subview
view.addSubview(controller.view)
controller.didMove(toParent: self)
For more information about why this addChild (previously called addChildViewController) and didMove(toParent:) (previously called didMove(toParentViewController:)) are necessary, see WWDC 2011 video #102 - Implementing UIViewController Containment. In short, you need to ensure that your view controller hierarchy stays in sync with your view hierarchy, and these calls to addChild and didMove(toParent:) ensure this is the case.
Also see Creating Custom Container View Controllers in the View Controller Programming Guide.
By the way, the above illustrates how to do this programmatically. It is actually much easier if you use the "container view" in Interface Builder.
Then you don't have to worry about any of these containment-related calls, and Interface Builder will take care of it for you.
For Swift 2 implementation, see previous revision of this answer.
Thanks to Rob.
Adding detailed syntax for your second observation :
let controller:MyView = self.storyboard!.instantiateViewControllerWithIdentifier("MyView") as! MyView
controller.ANYPROPERTY=THEVALUE // If you want to pass value
controller.view.frame = self.view.bounds
self.view.addSubview(controller.view)
self.addChildViewController(controller)
controller.didMoveToParentViewController(self)
And to remove the viewcontroller :
self.willMoveToParentViewController(nil)
self.view.removeFromSuperview()
self.removeFromParentViewController()
This code will work for Swift 4.2.
let controller = self.storyboard!.instantiateViewController(withIdentifier: "secondViewController") as! SecondViewController
controller.view.frame = self.view.bounds
self.view.addSubview(controller.view)
self.addChild(controller)
controller.didMove(toParent: self)
For Add and Remove ViewController
var secondViewController :SecondViewController?
// Adding
func add_ViewController() {
let controller = self.storyboard?.instantiateViewController(withIdentifier: "secondViewController")as! SecondViewController
controller.view.frame = self.view.bounds
self.view.addSubview(controller.view)
self.addChild(controller)
controller.didMove(toParent: self)
self.secondViewController = controller
}
// Removing
func remove_ViewController(secondViewController:SecondViewController?) {
if secondViewController != nil {
if self.view.subviews.contains(secondViewController!.view) {
secondViewController!.view.removeFromSuperview()
}
}
}
Thanks to Rob, Updated Swift 4.2 syntax
let controller:WalletView = self.storyboard!.instantiateViewController(withIdentifier: "MyView") as! WalletView
controller.view.frame = self.view.bounds
self.view.addSubview(controller.view)
self.addChild(controller)
controller.didMove(toParent: self)
func callForMenuView()
{
if(!isOpen)
{
isOpen = true
let menuVC : MenuViewController = self.storyboard!.instantiateViewController(withIdentifier: "menu") as! MenuViewController
self.view.addSubview(menuVC.view)
self.addChildViewController(menuVC)
menuVC.view.layoutIfNeeded()
menuVC.view.frame=CGRect(x: 0 - UIScreen.main.bounds.size.width, y: 0, width: UIScreen.main.bounds.size.width-90, height: UIScreen.main.bounds.size.height);
UIView.animate(withDuration: 0.3, animations: { () -> Void in
menuVC.view.frame=CGRect(x: 0, y: 0, width: UIScreen.main.bounds.size.width-90, height: UIScreen.main.bounds.size.height);
}, completion:nil)
}else if(isOpen)
{
isOpen = false
let viewMenuBack : UIView = view.subviews.last!
UIView.animate(withDuration: 0.3, animations: { () -> Void in
var frameMenu : CGRect = viewMenuBack.frame
frameMenu.origin.x = -1 * UIScreen.main.bounds.size.width
viewMenuBack.frame = frameMenu
viewMenuBack.layoutIfNeeded()
viewMenuBack.backgroundColor = UIColor.clear
}, completion: { (finished) -> Void in
viewMenuBack.removeFromSuperview()
})
}
Please also check the official documentation on implementing a custom container view controller:
https://developer.apple.com/library/content/featuredarticles/ViewControllerPGforiPhoneOS/ImplementingaContainerViewController.html#//apple_ref/doc/uid/TP40007457-CH11-SW1
This documentation has much more detailed information for every instruction and also describes how to do add transitions.
Translated to Swift 3:
func cycleFromViewController(oldVC: UIViewController,
newVC: UIViewController) {
// Prepare the two view controllers for the change.
oldVC.willMove(toParentViewController: nil)
addChildViewController(newVC)
// Get the start frame of the new view controller and the end frame
// for the old view controller. Both rectangles are offscreen.r
newVC.view.frame = view.frame.offsetBy(dx: view.frame.width, dy: 0)
let endFrame = view.frame.offsetBy(dx: -view.frame.width, dy: 0)
// Queue up the transition animation.
self.transition(from: oldVC, to: newVC, duration: 0.25, animations: {
newVC.view.frame = oldVC.view.frame
oldVC.view.frame = endFrame
}) { (_: Bool) in
oldVC.removeFromParentViewController()
newVC.didMove(toParentViewController: self)
}
}
Swift 5.1
To Add:
let controller = storyboard?.instantiateViewController(withIdentifier: "MyViewControllerId")
addChild(controller!)
controller!.view.frame = self.containerView.bounds
self.containerView.addSubview((controller?.view)!)
controller?.didMove(toParent: self)
To remove:
self.containerView.subviews.forEach({$0.removeFromSuperview()})
I have sideViewController with a button and Action, which present new view controller by clicking this button.
class sideViewController: UIViewController {
#IBOutlet var buttonVC1 : UIButton!
#IBAction func goToVC1 () {
var VC1 = self.storyboard.instantiateViewControllerWithIdentifier("ViewController") as ViewController
presentViewController(VC1, animated:true, completion: nil)
}
}
I use this in main view controller:
class ViewController: UIViewController {
var menu : sideViewController!
override func viewDidLoad() {
super.viewDidLoad()
menu = self.storyboard.instantiateViewControllerWithIdentifier("menu") as sideViewController
menu.view.frame = CGRect(x: 0, y: 0, width: 160, height: 480)
view.addSubview(menu.view)
}
when I click this button, the problem is: "Presenting view controllers on detached view controllers is discouraged"
What should I do to fix this?
I just ran into this same warning myself, and realized that I'm getting it because when I was calling
self.presentViewController
I was calling it on a view controller that wasn't attached to the UIWindow through the view hierarchy. You need to change what your doing to delay calling presentViewController until you know the view is on the view stack. This would be done in ViewDidLoad or ViewDidAppear, or if your coming from a background state, waiting until your app is in the active state
Use this to make sure you are on the main thread
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.presentViewController(VC1, animated: true, completion: nil)
})
Problem
iOS is complaining that some other view(the detached view) which came after the main view is presenting something. It can present it, which it does apparently, but it's discouraged as it's not a good practice to do so.
Solution
Delegate/protocol pattern is suitable to solve this issue. By using this pattern, the action will be triggered inside the SideVC although this trigger will be sent to the MainVC and be performed there.
Therefore, since the action will be triggered by the MainVC, from iOS's perspective, it will all be safe and sound.
Code
SideVC:
protocol SideVCDelegate: class {
func sideVCGoToVC1()
}
class sideVC: UIViewController {
weak var delegate: SideVCDelegate?
#IBOutlet var buttonVC1: UIButton!
#IBAction func goToVC1 () {
delegate.sideVCGoToVC1()
}
MainVC
class MainVC: UIViewController, SideVCDelegate {
var menu: sideVC!
override func viewDidLoad() {
super.viewDidLoad()
menu = self.storyboard?.instantiateViewControllerWithIdentifier("menu") as sideViewController
menu.delegate = self
menu.view.frame = CGRect(x: 0, y: 0, width: 160, height: 480)
view.addSubview(menu.view)
}
// MARK: - SideViewControllerDelegate
func sideViewControllerGoToVC1() {
menu.view.removeFromSuperview()
var VC1 = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController") as ViewController
presentViewController(VC1, animated:true, completion: nil)
}
}
Note
Apart from the question you've asked, the below lines seems somewhat vague.
var VC1 = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController") as ViewController
menu.view.frame = CGRect(x: 0, y: 0, width: 160, height: 480)
You're obtaining a view controller from your storyboard which has a frame when you designed it inside Interface Builder but you're changing it afterwards. It's not a good practice to play with the frames of views once they're created.
Maybe you've intended to do something else but most likely, it's a problematic piece of code.
Swift 5
In the UIKit view hierarchy, view controllers can either be "attached" or "detached", which I put in quotes because they're never explained in documentation. From what I've observed, attached view controllers are simply view controllers that are directly chained to the key window.
Therefore, the nearest attached view controller would obviously be the root view controller itself, since it's directly owned by the key window. This is why presenting from the root view controller remedies warnings about presenting on detached view controllers.
To present a subsequent view controller (a second one), you must find the next nearest and available attached view controller (I say available because the root view controller is currently occupied presenting the current view controller; it cannot present any more view controllers). If the root is presenting a plain view controller (meaning, not a container view controller like a navigation controller), then the next nearest attached view controller is that view controller. You can present from self without any warnings, since it's directly chained to the root, which is directly chained to the key window. However, if the root presented a container view controller, like a navigation controller, then you could not present from any of its children, because they are not directly chained to the root—the parent/container is. Therefore, you would have to present from the parent/container.
To make this easier, you can subclass UIViewController and add a convenience method for finding the nearest available attached view controller.
class XViewController: UIViewController {
var rootViewController: UIViewController? {
return UIApplication.shared.keyWindow?.rootViewController
}
/* Returns the nearest available attached view controller
(for objects that seek to present view controllers). */
var nearestAvailablePresenter: UIViewController? {
guard let root = rootViewController else {
return nil
}
if root.presentedViewController == nil {
return root // the root is not presenting anything, use the root
} else if let parent = parent {
return parent // the root is currently presenting, find nearest parent
} else {
return self // no parent found, present from self
}
}
}
Usage
class SomeViewController: XViewController {
let modal = AnotherViewController()
nearestAvailablePresenter?.present(modal, animated: true, completion: nil)
}
Here this might help you. I got my error fixed with this
let time = dispatch_time(DISPATCH_TIME_NOW, Int64(0.001 * Double(NSEC_PER_SEC)))
dispatch_after(time, dispatch_get_main_queue(), { () -> Void in
self.performSegueWithIdentifier("SegueName", sender: self)
})
Good luck..