I'm having a very strange problem with the UINavigationController.
I found a very similar question here:
UINavigationController not popping UINavigationBar items
but the solution there had to do with the fact that the guy had added a category to NSMutableArray, and I'm not doing anything like that.
In short, the problem is this: I have a navigation controller and I'm pushing a few view controllers on it. Then when the 'back' button is tapped the view controller is popped, but the corresponding navigation item isn't. If I tap back again, then the navigation item is popped.
Besides, it only happens when using the back button from the navigation controller's navigation bar. If I call popViewController explicitly (for example from a button press), it works as expected.
And this only happens on my iPad running OS 3.2, but not on my iPod Touch running OS 3.0 or on the simulator.
I've been trying to isolate the problem in a separate project from the rest of my app so I can experiment with it, but I can't get it to reproduce, though it occurs 100% of the times on specific views in my app.
I know that's not nearly enough information to get an specific answer, but I just wanted to know if anyone ever heard of a navigation controller not popping the navigation items as expected, just so I could have some clue as to where to investigate next.
Here's an example of the code I use to push a view controller, it's pretty straightforward, I'm not trying to do anything special with it:
// pushing a view controller from a button press (set up with interface builder)
- (IBAction) tappedExtras
{
ExtrasViewController *controller = [[ExtrasViewController alloc] initWithNibName:#"ExtrasViewController" bundle:nil];
[self.navigationController pushViewController:controller animated:YES];
[controller release];
}
note: in that example I'm using a custom view controller class called ExtrasViewController, but the problem happened with any kind of view controller I tried.
And here's a bit of code used to pop the view controller explicitly, also triggered by a button press set up with interface builder:
- (IBAction) cancelChanges
{
userCancelled = YES;
[self.navigationController popViewControllerAnimated:YES];
}
this works perfectly (popping the view controller explicitly), but on the exact same view controller if instead of tapping the button set up with interface builder you tap the back button on the navigation bar, the navigation item is not popped correctly.
I got the same issue with navigation that subsist after poping the third level pushed view controller.
The issue only appear in landscape on iPad. No issue on the iPhone (3.1.3 & 4.0). Of course, it's ok on the simulator.
Related
I don't want to let the navigation controller show its navigation bar in the whole project.
Now there are three view controllers
(1) Login view controller
(2) Sign up view controller
(3) Home view controller.
I just hope to use action(which can be triggered by any kind of event, i.e. drag gesture, not necessary the pressing button) to switch between these view controllers. But I found once I get to the "signup view controllers", I can not go back to the login view controller, since there is no "BACK" navigation bar.
Questions:
How "PUSH" in one view controller, then "POP" in the other view controller?
Or there is some different way to solve this problem?
Thank you so much, any suggestion is great.
To programmaticaly go backward in a navigation controller's navigation stack, call this method:
[self popViewControllerAnimated:YES];
When and where you call this is up to how you want your app to flow. Essentially, the default navigation controller calls this automatically when the navbar's back button is pressed. But if you hide the navbar and still need to pop back, you can call this method to pop back.
As for pushing forward, it's simply a matter of creating a Push segue on the storyboard, giving it a name, and then in your code, call this method:
[self performSegueWithIdentifier:#"segue_YOUR_SEGUE_ID" sender:self];
On the question of your app, what probably makes most sense is for the login view be a view by itself. It should contain a modal segue to a sign up view for new users as well as a modal segue to the home view controller (which may or may not need to be embedded in a navigation controller).
Performing a modal segue works exactly the same as a push segue (if you're using storyboards. Hook up the segue, choose a modal segue, then call the performSegueWithIdentifier: method in your code when you need the segue to occur.
Dismissing a modal view is slightly different, but still quite simple. It goes like this:
[self dismissViewControllerAnimated:YES completion:nil];
It's fairly check to do with an 'if' statement...
if (self.navigationController.navigationBarHidden == NO) {
//YOUR ACTION
}
Hope that helps!
Im relatively new to iOS programming and have been making a recipe based app for the iPad. I've looked around at a lot of answers and can't seem to solve my problem so ill explain how my app is laid out.
Navigation controller -> ViewController -Modal segue -> PreviewViewController -modal segue -> Navigation Controller -> RecipeViewController
Within my RecipeViewController i have a button that when pressed i want it to go back to the "home" screen which for these purposes is the "ViewController".
Here is the code for the button action in "RecipeViewController":
- (IBAction)homeB:(id)sender {
ViewController* viewController = [[ViewController alloc]init];
[self.navigationController pushViewController:viewController animated:YES];
}
However, when i press this button the ViewController is displayed, but the screen is greyed out and i can have no interaction with the screen. I can't post an image of what the screen looks like as i don't have enough reputation yet but i will update it when i can.
I have tried other ways of displaying it such as connecting a segue in the storyboard between the button and the "ViewController" and then activating the segue when the button is pressed. But this messes up other parts of my code as i have to re allocate and initialise the home screen. Would appreciate any help as to why it is coming up with the greyed out screen that cannot be interacted with.
Also just some more notes:
self.navigationController
does not return nil so it is seen, and no errors are displayed when the button is pressed.
Thanks
If you're really doing segues, then I presume this was made in a storyboard. If that's the case, then you should use an unwind segue to get back to ViewController. You do this by adding an IBAction in ViewController that looks like this:
-(IBAction)comingBackFromRecipe:(UIStoryboardSegue*)sender {
NSLog(#"I'm back");
}
The important point is that the sender type be UIStoryboardSegue. Then in IB, in the RecipeViewController, you control drag from your button to the green "Exit" icon at the bottom of the controller. When you let go, you should see the method that you wrote in ViewController -- connect it to that. This will get you back to the same instance of ViewController that you started with.
It's hard to tell without seeing a screenshot, but from what i understand, if you want to go back to the home screen, you shouldn't be pushing a new view controller (unless you really want to add it to the stack?)
To go back to the "home" screen, you should try this:
[self.navigationController popToViewController:viewController animated:YES];
or if your home screen is the root, simply use this:
[self.navigationController popToRootViewControllerAnimated:YES];
Thanks for the responses everyone, i figured out my problem though. My structure was wrong and i realised that i didn't need to have another navigation controller for the Recipe view Controller as i wasn't pushing anywhere from there. So incase anyone else has a similar problem my structure is now as follows:
Navigation Controller -> View Controller -Modal Segue -> PreviewViewController - ModalSegue -> RecipeViewController
I removed the Navigation controller between PreviewViewController and RecipeViewController. This means that they are all modal view controllers. So to get back from the RecipeViewController to the home screen which is "ViewController" i just needed to dismiss the hierarchy of modal views with the following code:
UIViewController * parent = self.presentingViewController;
[parent.presentingViewController dismissViewControllerAnimated:YES completion:nil];
I went back two stages so that both the PreviewViewController and the RecipeViewController where dismissed.
Works great now, thanks for the help anyway everyone.
I have a UITableViewController that pushes a UIViewController using a UINavigationController:
[self.navigationController pushViewController:detailViewController animated:YES];
In the detailViewController, I present a modal view when the user taps a button (a MFMessageComposeViewController for sending an SMS message) and then dismiss it, like this:
[self presentModalViewController:smsViewController animated:YES];
...
// user pushes Send or Cancel button on the view
...
[self dismissModalViewControllerAnimated:YES];
The SMS modal view dismisses properly, but now when I click the "Back" button on the UINavigationBar, the views don't animate back to the table view. The detail view just disappears and the UITableViewController's view is there. The Back button animates and fades and the selected table cell still has the fading blue effect, but there's no view animation.
Does anyone know why the views don't animate properly? If I don't open the SMS modal view, then the animation works properly, so I'm pretty sure it's caused somehow by the modal behavior.
Here's how my Interface Builder view arrangement looks for this Tab Bar Item:
Please change this line [self.navigationController pushViewController:detailViewController];
to
[self.navigationController pushViewController:detailViewController animated:YES];
And check whether your detailView's viewWillAppear and viewWillDisappear methods set toYES.
I discovered my problem. I am using a custom UITabBarController subclass that overrides -(void)viewWillAppear:(BOOL)animated with some custom tab bar handling. However, I wasn't calling [super viewWillAppear:animated] in the overridden method. Yes, a sad day in my developer life. It still seems odd to me that this would cause the behavior I experienced, but I'm certain it's now fixed due to this change.
Interestingly, the modal push/dismiss animation works properly without the [super viewWillAppear:animated] call in the iPhone 4.3 simulator. But, it does not work in the iPhone 5.0 or 5.1 simulators. (I used a non-MFMessageComposeViewController to text the modal behavior on the iPhone simulator since SMS isn't supported on the simulator).
I'm writing an iPhone app that is based on a UINavigationController. I'm pulling data from a server that sometime returns bogus links. I open each link by pushing a webview viewcontroller. I want to be able to include some error handling. I know if the link is no good. So I want to be able to pop the webview view controller as soon as I know that my webview has encountered an error.
Currently, I've tried using the following code:
[self.navigationController popViewControllerAnimated:YES];
I then get a Navigation bar with nothing displayed in it, but if I click where the "back" button should be it operates appropriately. The title pops up when I click where the "back" button should be. The view where the viewcontrollers usually display there content is blank white too even though I'm popping back to a UITableViewController.
I've tried this as a workaround:
UINavigationController *nav = self.navigationController;
[self.navigationController popViewControllerAnimated:YES];
[nav.visibleViewController.view setNeedsDisplay];
I've checked the viewControllers array in the UINavigationController and it has the right viewcontrollers in it (ie it has removed the viewcontroller for the webview).
I also tried putting code in the viewWillAppear of the viewcontroller I'm popping back to, but the method is never getting called.
I'm looking for a way to force the UINavigationController to reload the same way that you can call reloadData on a UITableView.
Any help would be greatly appreciated.
I saw something like this on my app where I was using a navigation bar I added in Interface Builder on the root view of a navigation controller and then programmatically creating the nav bar and its subviews for the second view. When I would pop the second view to return to the first view I would hide the self.navigationcontroller bar which would show the white space underneath until the IB nav bar of the previous view appeared. To fix this I decided to stick with programmatically creating all my navbars which fixed the issue for me.
TL;DR - if you are using both IB and programmatically made navbars this can happen when popping views, stick with one or the other for all the navbars yo
Trying to fix a very strange error, i have 3 view controllers that start from the app delegate and push each other accordingly. The 3rd view controller then has a toolbar button that calls the code here:
-(void)showEventBrowser;
{
accelManeger.delegate = nil;
NSLog(#"%u",[self.navigationController.viewControllers count]);
[self.navigationController popToRootViewControllerAnimated:NO];
}
This works the first time round but when i come back to this view controller and try again. Firstly it reports that there are 3 view controllers on the stack. It then deallocs the 2nd view controller in the stack and doesnt crash but will not go any further. If i hit the button again it says there are no view controllers on the stack and fails to respond.
I have logs for all the viewdid, viewwill, e.t.c in each view controller and there appears to be no odd behaviour. Also no memory warnings from any view controllers.
Why would this work once through but not the second time ?
Well i Fixed this.
I was trying to poptorootviewcontroller from a viewcontroller that had no view but isntead just displayed a UIImagepickercontroller. Even when attempting to dissmiss this modalviewcontroller first, (even with a delay), i still had the same problem. I instead changed the viewcontroller in question to a UIMagepickercontroller subclass and handle the present and dismiss in another viewcontroller.
Lesson learnt, dont pop to root with UIImagepickercontroller modal view ontop.