Attempt to present UIViewController on UIViewController whose view is not in the window hierarchy
IosCocoa TouchIos6ViewsHierarchyIos Problem Overview
Just started using Xcode 4.5 and I got this error in the console:
>Warning: Attempt to present < finishViewController: 0x1e56e0a0 > on < ViewController: 0x1ec3e000> whose view is not in the window hierarchy!
The view is still being presented and everything in the app is working fine. Is this something new in iOS 6?
This is the code I'm using to change between views:
UIStoryboard *storyboard = self.storyboard;
finishViewController *finished =
[storyboard instantiateViewControllerWithIdentifier:@"finishViewController"];
[self presentViewController:finished animated:NO completion:NULL];
Ios Solutions
Solution 1 - Ios
Where are you calling this method from? I had an issue where I was attempting to present a modal view controller within the viewDidLoad
method. The solution for me was to move this call to the viewDidAppear:
method.
My presumption is that the view controller's view is not in the window's view hierarchy at the point that it has been loaded (when the viewDidLoad
message is sent), but it is in the window hierarchy after it has been presented (when the viewDidAppear:
message is sent).
Caution
If you do make a call to presentViewController:animated:completion:
in the viewDidAppear:
you may run into an issue whereby the modal view controller is always being presented whenever the view controller's view appears (which makes sense!) and so the modal view controller being presented will never go away...
Maybe this isn't the best place to present the modal view controller, or perhaps some additional state needs to be kept which allows the presenting view controller to decide whether or not it should present the modal view controller immediately.
Solution 2 - Ios
Another potential cause:
I had this issue when I was accidentally presenting the same view controller twice. (Once with performSegueWithIdentifer:sender:
which was called when the button was pressed, and a second time with a segue connected directly to the button).
Effectively, two segues were firing at the same time, and I got the error: Attempt to present X on Y whose view is not in the window hierarchy!
Solution 3 - Ios
viewWillLayoutSubviews
and viewDidLayoutSubviews
(iOS 5.0+) can be used for this purpose. They are called earlier than viewDidAppear.
Solution 4 - Ios
For Display any subview to main view,Please use following code
UIViewController *yourCurrentViewController = [UIApplication sharedApplication].keyWindow.rootViewController;
while (yourCurrentViewController.presentedViewController)
{
yourCurrentViewController = yourCurrentViewController.presentedViewController;
}
[yourCurrentViewController presentViewController:composeViewController animated:YES completion:nil];
For Dismiss any subview from main view,Please use following code
UIViewController *yourCurrentViewController = [UIApplication sharedApplication].keyWindow.rootViewController;
while (yourCurrentViewController.presentedViewController)
{
yourCurrentViewController = yourCurrentViewController.presentedViewController;
}
[yourCurrentViewController dismissViewControllerAnimated:YES completion:nil];
Solution 5 - Ios
I also encountered this problem when I tried to present a UIViewController
in viewDidLoad
. James Bedford's answer worked, but my app showed the background first for 1 or 2 seconds.
After some research, I've found a way to solve this using the addChildViewController
.
- (void)viewDidLoad
{
...
[self.view addSubview: navigationViewController.view];
[self addChildViewController: navigationViewController];
...
}
Solution 6 - Ios
Probably, like me, you have a wrong root viewController
I want to display a ViewController
in a non-UIViewController
context,
So I can't use such code:
[self presentViewController:]
So, I get a UIViewController:
[[[[UIApplication sharedApplication] delegate] window] rootViewController]
For some reason (logical bug), the rootViewController
is something other than expected (a normal UIViewController
). Then I correct the bug, replacing rootViewController
with a UINavigationController
, and the problem is gone.
Solution 7 - Ios
TL;DR You can only have 1 rootViewController and its the most recently presented one. So don't try having a viewcontroller present another viewcontroller when it's already presented one that hasn't been dismissed.
After doing some of my own testing I've come to a conclusion.
If you have a rootViewController that you want to present everything then you can run into this problem.
Here is my rootController code (open is my shortcut for presenting a viewcontroller from the root).
func open(controller:UIViewController)
{
if (Context.ROOTWINDOW.rootViewController == nil)
{
Context.ROOTWINDOW.rootViewController = ROOT_VIEW_CONTROLLER
Context.ROOTWINDOW.makeKeyAndVisible()
}
ROOT_VIEW_CONTROLLER.presentViewController(controller, animated: true, completion: {})
}
If I call open twice in a row (regardless of time elapsed), this will work just fine on the first open, but NOT on the second open. The second open attempt will result in the error above.
However if I close the most recently presented view then call open, it works just fine when I call open again (on another viewcontroller).
func close(controller:UIViewController)
{
ROOT_VIEW_CONTROLLER.dismissViewControllerAnimated(true, completion: nil)
}
What I have concluded is that the rootViewController of only the MOST-RECENT-CALL is on the view Hierarchy (even if you didn't dismiss it or remove a view). I tried playing with all the loader calls (viewDidLoad, viewDidAppear, and doing delayed dispatch calls) and I have found that the only way I could get it to work is ONLY calling present from the top most view controller.
Solution 8 - Ios
Swift 5 - Background Thread
If an alert controller is executed on a background thread then the "Attempt to present ... whose view is not in the window hierarchy" error may occur.
So this:
present(alert, animated: true, completion: nil)
Was fixed with this:
DispatchQueue.main.async { [weak self] in
self?.present(alert, animated: true, completion: nil)
}
Solution 9 - Ios
I had similar issue on Swift 4.2 but my view was not presented from the view cycle. I found that I had multiple segue to be presented at same time. So I used dispatchAsyncAfter.
func updateView() {
DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) { [weak self] in
// for programmatically presenting view controller
// present(viewController, animated: true, completion: nil)
//For Story board segue. you will also have to setup prepare segue for this to work.
self?.performSegue(withIdentifier: "Identifier", sender: nil)
}
}
Solution 10 - Ios
My issue was I was performing the segue in UIApplicationDelegate
's didFinishLaunchingWithOptions
method before I called makeKeyAndVisible()
on the window.
Solution 11 - Ios
In my situation, I was not able to put mine in a class override. So, here is what I got:
let viewController = self // I had viewController passed in as a function,
// but otherwise you can do this
// Present the view controller
let currentViewController = UIApplication.shared.keyWindow?.rootViewController
currentViewController?.dismiss(animated: true, completion: nil)
if viewController.presentedViewController == nil {
currentViewController?.present(alert, animated: true, completion: nil)
} else {
viewController.present(alert, animated: true, completion: nil)
}
Solution 12 - Ios
You can call your segues or present, push codes inside this block:
override func viewDidLoad() {
super.viewDidLoad()
OperationQueue.main.addOperation {
// push or present the page inside this block
}
}
Solution 13 - Ios
I had the same problem. I had to embed a navigation controller and present the controller through it. Below is the sample code.
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UIImagePickerController *cameraView = [[UIImagePickerController alloc]init];
[cameraView setSourceType:UIImagePickerControllerSourceTypeCamera];
[cameraView setShowsCameraControls:NO];
UIView *cameraOverlay = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 768, 1024)];
UIImageView *imageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"someImage"]];
[imageView setFrame:CGRectMake(0, 0, 768, 1024)];
[cameraOverlay addSubview:imageView];
[cameraView setCameraOverlayView:imageView];
[self.navigationController presentViewController:cameraView animated:NO completion:nil];
// [self presentViewController:cameraView animated:NO completion:nil]; //this will cause view is not in the window hierarchy error
}
Solution 14 - Ios
If you have AVPlayer object with played video you have to pause video first.
Solution 15 - Ios
I had the same issue. The problem was, the performSegueWithIdentifier was triggered by a notification, as soon as I put the notification on the main thread the warning message was gone.
Solution 16 - Ios
I've ended up with such a code that finally works to me (Swift), considering you want to display some viewController
from virtually anywhere. This code will obviously crash when there is no rootViewController available, that's the open ending. It also does not include usually required switch to UI thread using
dispatch_sync(dispatch_get_main_queue(), {
guard !NSBundle.mainBundle().bundlePath.hasSuffix(".appex") else {
return; // skip operation when embedded to App Extension
}
if let delegate = UIApplication.sharedApplication().delegate {
delegate.window!!.rootViewController?.presentViewController(viewController, animated: true, completion: { () -> Void in
// optional completion code
})
}
}
Solution 17 - Ios
It's working fine try this.Link
UIViewController *top = [UIApplication sharedApplication].keyWindow.rootViewController;
[top presentViewController:secondView animated:YES completion: nil];
Solution 18 - Ios
In case it helps anyone, my issue was extremely silly. Totally my fault of course. A notification was triggering a method that was calling the modal. But I wasn't removing the notification correctly, so at some point, I would have more than one notification, so the modal would get called multiple times. Of course, after you call the modal once, the viewcontroller that calls it it's not longer in the view hierarchy, that's why we see this issue. My situation caused a bunch of other issue too, as you would expect.
So to summarize, whatever you're doing make sure the modal is not being called more than once.
Solution 19 - Ios
This kind of warning can mean that You're trying to present new View Controller
through Navigation Controller
while this Navigation Controller
is currently presenting another View Controller
. To fix it You have to dismiss currently presented View Controller
at first and on completion present the new one.
Another cause of the warning can be trying to present View Controller
on thread another than main
.
Solution 20 - Ios
I fixed it by moving the start()
function inside the dismiss
completion block:
self.tabBarController.dismiss(animated: false) {
self.start()
}
Start contains two calls to self.present()
one for a UINavigationController and another one for a UIImagePickerController
.
That fixed it for me.
Solution 21 - Ios
You can also get this warning when performing a segue from a view controller that is embedded in a container. The correct solution is to use segue from the parent of container, not from container's view controller.
Solution 22 - Ios
Have to write below line.
self.searchController.definesPresentationContext = true
instead of
self.definesPresentationContext = true
in UIViewController
Solution 23 - Ios
It happened to me that the segue in the storyboard was some kind of broken. Deleting the segue (and creating the exact same segue again) solved the issue.
Solution 24 - Ios
With Swift 3...
Another possible cause to this, which happened to me, was having a segue from a tableViewCell to another ViewController on the Storyboard. I also used override func prepare(for segue: UIStoryboardSegue, sender: Any?) {}
when the cell was clicked.
I fixed this issue by making a segue from ViewController to ViewController.
Solution 25 - Ios
I had this issue, and the root cause was subscribing to a button click handler (TouchUpInside) multiple times.
It was subscribing in ViewWillAppear, which was being called multiple times since we had added navigation to go to another controller, and then unwind back to it.
Solution 26 - Ios
With your main window, there will likely always be times with transitions that are incompatible with presenting an alert. In order to allow presenting alerts at any time in your application lifecycle, you should have a separate window to do the job.
/// independant window for alerts
@interface AlertWindow: UIWindow
+ (void)presentAlertWithTitle:(NSString *)title message:(NSString *)message;
@end
@implementation AlertWindow
+ (AlertWindow *)sharedInstance
{
static AlertWindow *sharedInstance;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sharedInstance = [[AlertWindow alloc] initWithFrame:UIScreen.mainScreen.bounds];
});
return sharedInstance;
}
+ (void)presentAlertWithTitle:(NSString *)title message:(NSString *)message
{
// Using a separate window to solve "Warning: Attempt to present <UIAlertController> on <UIViewController> whose view is not in the window hierarchy!"
UIWindow *shared = AlertWindow.sharedInstance;
shared.userInteractionEnabled = YES;
UIViewController *root = shared.rootViewController;
UIAlertController *alert = [UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleAlert];
alert.modalInPopover = true;
[alert addAction:[UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
shared.userInteractionEnabled = NO;
[root dismissViewControllerAnimated:YES completion:nil];
}]];
[root presentViewController:alert animated:YES completion:nil];
}
- (instancetype)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
self.userInteractionEnabled = NO;
self.windowLevel = CGFLOAT_MAX;
self.backgroundColor = UIColor.clearColor;
self.hidden = NO;
self.rootViewController = UIViewController.new;
[NSNotificationCenter.defaultCenter addObserver:self
selector:@selector(bringWindowToTop:)
name:UIWindowDidBecomeVisibleNotification
object:nil];
return self;
}
/// Bring AlertWindow to top when another window is being shown.
- (void)bringWindowToTop:(NSNotification *)notification {
if (![notification.object isKindOfClass:[AlertWindow class]]) {
self.hidden = YES;
self.hidden = NO;
}
}
@end
Basic usage that, by design, will always succeed:
[AlertWindow presentAlertWithTitle:@"My title" message:@"My message"];
Solution 27 - Ios
Sadly, the accepted solution did not work for my case. I was trying to navigate to a new View Controller right after unwind from another View Controller.
I found a solution by using a flag to indicate which unwind segue was called.
@IBAction func unwindFromAuthenticationWithSegue(segue: UIStoryboardSegue) {
self.shouldSegueToMainTabBar = true
}
@IBAction func unwindFromForgetPasswordWithSegue(segue: UIStoryboardSegue) {
self.shouldSegueToLogin = true
}
Then present the wanted VC with present(_ viewControllerToPresent: UIViewController)
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
let storyboard = UIStoryboard(name: "Main", bundle: nil)
if self.shouldSegueToMainTabBar {
let mainTabBarController = storyboard.instantiateViewController(withIdentifier: "mainTabBarVC") as! MainTabBarController
self.present(mainTabBarController, animated: true)
self.shouldSegueToMainTabBar = false
}
if self.shouldSegueToLogin {
let loginController = storyboard.instantiateViewController(withIdentifier: "loginVC") as! LogInViewController
self.present(loginController, animated: true)
self.shouldSegueToLogin = false
}
}
Basically, the above code will let me catch the unwind from login/SignUp VC and navigate to the dashboard, or catch the unwind action from forget password VC and navigate to the login page.
Solution 28 - Ios
I fixed this error with storing top most viewcontroller into constant which is found within while cycle over rootViewController:
if var topController = UIApplication.shared.keyWindow?.rootViewController {
while let presentedViewController = topController.presentedViewController {
topController = presentedViewController
}
topController.present(controller, animated: false, completion: nil)
// topController should now be your topmost view controller
}
Solution 29 - Ios
I found this bug arrived after updating Xcode, I believe to Swift 5. The problem was happening when I programatically launched a segue directly after unwinding a view controller.
The solution arrived while fixing a related bug, which is that the user was now able to unwind segues by swiping down the page. This broke the logic of my program.
It was fixed by changing the Presentation mode on all the view controllers from Automatic to Full Screen.
You can do it in the attributes panel in interface builder. Or see this answer for how to do it programatically.
Solution 30 - Ios
Swift 5
I call present in viewDidLayoutSubviews
as presenting in viewDidAppear
causes a split second showing of the view controller before the modal is loaded which looks like an ugly glitch
make sure to check for the window existence and execute code just once
var alreadyPresentedVCOnDisplay = false
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// we call present in viewDidLayoutSubviews as
// presenting in viewDidAppear causes a split second showing
// of the view controller before the modal is loaded
guard let _ = view?.window else {
// window must be assigned
return
}
if !alreadyPresentedVCOnDisplay {
alreadyPresentedVCOnDisplay = true
present(...)
}
}
Solution 31 - Ios
I just had this issue too, but it had nothing to do with the timing. I was using a singleton to handle scenes, and I set it as the presenter. In other words "Self" wasn't hooked up to anything. I just made its inner "scene" the new presenter and voila, it worked. (Voila loses its touch after you learn its meaning, heh).
So yeah, it's not about "magically finding the right way", it's about understanding where your code stands and what it's doing. I'm happy Apple gave such a plain-English warning message, even with emotion to it. Kudos to the apple dev who did that!!
Solution 32 - Ios
If other solutions does not look good for some reason, you can still use this good old workaround
of presenting with the delay of 0, like this:
dispatch_after(0, dispatch_get_main_queue(), ^{
finishViewController *finished = [self.storyboard instantiateViewControllerWithIdentifier:@"finishViewController"];
[self presentViewController:finished animated:NO completion:NULL];
});
While I've seen no documented guarantee that your VC would be on the view hierarchy on the time dispatch block is scheduled to execution, I've observed it would work just fine.
Using delay of e.g. 0.2 sec is also an option. And the best thing - this way you don't need to mess with boolean variable in viewDidAppear:
Solution 33 - Ios
This works for to present any view controller ,if you have navigation controller available. self.navigationController?.present(MyViewController, animated: true, completion: nil) Also , I can able to present alerts and mail controller also.
Solution 34 - Ios
The message appear as warning and sometimes the code refuses to work. (!Needs Citation: Newer SDK's might have strict rules).
I have encountered it for more than one reason, mostly complicated viewcontroller scenarios. Here's an example.
Scenario: MainViewController (responsible to load: ViewControllerA & ViewControllerB)
Present ViewControllerA
from MainViewController
and without dismissing the ViewControllerA
you try to present viewControllerB
from MainViewController
(using a delegate method).
In this scenario, you'd have to make sure your ViewControllerA is dismissed and then the ViewControllerB is called.
Because after presenting ViewControllerA (ViewControllerA becomes responsible for displaying views and viewcontrollers and when MainViewController attempts to load another viewcontoller, it refuses to work with throwing a warning).
Solution 35 - Ios
This happened to me when I was trying to present onto my navigationController when its view has not been presented onto the view hierarchy yet. The way I solved this is to listen to the NavigationControllerDelegate's didShow method. Once the didShow method is called, I know I can present onto my navigationController.
Note: using dispatchQueueAsync.await(.now()) { //present }
does work, but it is hacky and prone to bugs if the view takes long to display onto the view hierarchy.