I have two View Controller. In the first I do some stuff and then I can push the second View Controller by clicking a button (the button connected with the other ViewController in the storyboard). There I can do some settings and so on. I get back to the first View Controller with the button "Done". But then the ViewDidLoad method is called again and all the "stuff" (text in textfields, ...) is gone.
I hope you guys understand my problem.
Why? And how can I disable this?
How are you going back to the first view controller from the second one? I think your problem is you're re-instantiating the first view controller when the user hits "Done".
Instead, you should be using either "popViewControllerAnimated" or "dismissViewControllerAnimated" to go back to the first view controller.
e.g: (one of these 2 should work):
[self.navigationController popViewControllerAnimated:YES];
[self dismissViewControllerAnimated:YES completion:nil];
Maybe the firstViewController is unLoaded because of receiving memory warning. So when it opened again, it calls ViewDidLoad
Related
I am trying to segue back to a home screen and pop everything from the stack (of views?)
I am using UINavigationController:
[self.navigationController popToRootViewControllerAnimated:YES];
Where shall I call this method? I have tried in -(void) prepareForSegue which does not work.
Basically I want to make sure when I go back to home screen there is no back button on the left of the title.
Home screen here refers to the welcome screen of my App.
I am not sure which part of my code shall be posted. Please comment if you need to see my code.
Thank you in advance.
Assuming you're using a Storyboard, and a UIButton declared over there is the one that triggers that action you wanna perform, you should declare an IBAction: -(IBAction)buttonPressed:(id)sender; in the .h and implement it in the .m. Inside that method should appear that [self.navigationController popToRootViewControllerAnimated:YES]; code. Also remember to attach that action to that UIButton when touch up inside in the storyboard.
Hope it helped!
I think your confusion is around the concepts of what a segue is and how it relates to the navigation controller stack. The stack is exactly the same as the basic data structure stack (http://en.m.wikipedia.org/wiki/Stack_(abstract_data_type)) in that it's a last-in-first-out store. When you segue, you're normally adding to that stack, e.g. Pushing a new VC onto the stack. A back button in most cases would not be doing that. It would be popping, or removing from the stack. Which is why you probably wouldn't call pop methods from the prepareForSegue method. Instead try calling it at some other point, like when they tap the back button, or after some action has taken place.
I'm trying to get a storyboard to bring the user back to the first screen of a storyboard when a button is pressed.
I have the button click hooked up and the method is hit when it's tapped but it's either doing nothing or crashing the app depending on what I've got in that method (I've tried so many things at this stage that I can't remember the original setup)
The best I can achieve is that once tapped the user gets brought to the third screen in the storyboard, rather than the first.
Here's the storyboard, I want to get the user to move from the button circled in red back to the very first view controller (top left of screenshot).
Maybe the storyboard layout will help people, I'll post some of the various methods I've tried as well.
Here's the method
- (IBAction)done:(id)sender
{
//Multitude of attempts have been in here, either they don't do
//anything or they just send the user back to the NEW REPORT screen.
//Button does nothing in these following events
[self.navigationController popToRootViewControllerAnimated:YES];
[self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:0] animated:YES];
}
If you want to start fresh, have the button instantiate a new instance of the first controller, and set it as the window's root view controller:
FirstViewController *first = [self.storyboard instantiateViewControllerWithIdentifier:#"First"];
self.view.window.rootViewController = first;
It's not clear to me exactly how you're getting to that controller with the button in question, but you might want to put dealloc methods in all your controllers with a log to see if all are getting deallocated at some point in your navigation, and when you go back to the new first controller as I've outlined above.
I have a view in which a user selects an action to take and on that next screen there is a save and a back button. For both of the buttons the last line is dismissViewControllerAnimated:.
I need a way to make the 1st screen show only if the back button is used. save should send back to the main screen/rootViewController I am fairly new to iOS but not programming in general and just need a nudge in the right direction.
Could I set a bool flag to show or not? Maybe I can set the Tag on the view and then check that in the other screens on save/back? I assume I can check the parent view.
Sorry if this is a dup but I cant find anything specifically for this.
EDIT: I am not using a nav controller and am showing the views modally.
The answer will vary depending on how your UIViewControllers are structured and setup. If you're using a uinavigationcontroller then you can POP to the root view controller using:
[self.navigationController popViewControllerAnimated:YES];
If you're presenting your UIViewControllers modally, you can try to dismiss the presenting View Controllers of your modal view controller using the presentingViewController property:
[[[self presentingViewController] presentingViewController] dismissViewControllerAnimated:YES completion:nil];
You may also want to take a look at Unwind Segues if you're using a Storyboard:
What are Unwind segues for and how do you use them?
Finally, as far as determining whether the back button is pressed or another button - that depends on how the app is setup. You'll need to use your own logic (probably if / then statements or case / switch) to determine which button was pressed. You also may want to check out the sender argument in IBActions.
John, to have a UINavigationViewController return to it's root viewcontroller, you use:
[nameOfNavController popToRootViewControllerAnimated:YES];
The other guys are correct that the information you've provided is definitely not enough to determine exactly what you need to do.
You can use the presentingViewController property of a modal view controller to access it's presenting controller.
It turns out that I was using the terminology wrong. I am presenting all views modally and that is the issue, there is no navigation controller. I ended up using NSNotification to build a listener and had the main view controller listen and then dismiss the view and hence show itself. Worked a treat.
here is the link to the code I ended up with.
http://iphonedevsdk.com/discussion/114737/view-heirarchy-issues-possibly-from-the-camera
Hopefully this helps someone else.
I'm having a weird issue with a navigation controller's back button animation:
my app has a tab bar control with 3 tabs, one of them has a navigation controller with two subsequent view controllers, the first one just show a master table and the second one details, the problem comes when I tap the back button from the detail view controller, instead of slide back to the master view controller it just pops the view without animation.
I've noticed that if I first go to another tab, and then return again to this one, the animation will trigger normally.
I've rebuilt the whole app navigation from scratch but the problem still persist, any help is appreciated.
Thanks in advance!.
Edit: More info added
This is how my storyboard looks like in that particular branch:
Here's the prepareForSegue from "Partidos Activos" view controller:
#pragma mark - Segues
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
if ([segue.identifier isEqualToString:#"PartidosEnDia"]) {
PartidosActivosEnFecha *paf = segue.destinationViewController;
CalendarCell *senderCell = (CalendarCell *)sender;
paf.datos = senderCell.dataDic;
}
}
Both viewController viewDidLoad methods are calling super at the start of the method.
As I told before, if I just tap on other tab and then come back to this one, the slide back animation from "Partidos Activos En Fecha" viewController works as expected, it's only when I start the application and go directly to this viewController when the slide back animation doesn't work, and it just gets to the caller viewController without animation.
Hope I added enough info, if not just tell me and I will add it again.
I finally found where the problem was, I was missing a call to super in the viewDidAppear method but in UITabBarController!, I was checking only viewControllers for the tabs but not the tabbarviewcontroller. #rdelmar was right.
I had the exact same problem. The cause for me was an empty viewDidAppear:animated method in my UITabBarController. Once I deleted that method, the animation worked normally again.
I think this it's what you want. If I understand, your problem is handle the stack of the navigation controller right? So, check that link.
I got two viewControllers using a navigation bar. The first viewController displays some data I change on the second viewController.
So if I load the second viewController, a back button appears in the NavBar and I can change my values (and they are stored, I used the debugger). My problem is, after hitting the backButton to come to my firstView Controller, it does not call it's viewDidLoad method. It's clear, that there are no updated values at all, when this function is not called.
At the first start, the viewDidLoad method is called and does what I want it to do. After going back and forth between the viewControllers the method is not called again.
Any solutions?
Thanks!
EDIT:
SOLVED
I did not want to delete my question, maybe someone needs this too:
This method is called every time the view appears, it is probably not defined by default:
-(void)viewDidAppear:(BOOL)animated
{
NSLog(#"View appeared.");
}
But the update code (like [[self view] setNeedsDisplay];) in viewWillAppear.
To make it clear: viewDidLoad is called when your view is loaded. This happens at the first time the view is going to be displayed. When you then navigate to the next view the first view can (depending on your code) still be loaded. Therefore when you navigate back to that view viewDidLoad won't be called because the view is still there.
But every time the view is going to be shown (for example when you navigate back to this view) the method viewWillAppear and viewDidAppear will be called.
Hope that helps.
ViewDidLoad method will get called when there is view controller allocation-initialization happens. In the case of moving back in navigation controller, it is not creating any new view controllers, it is reusing previous references from navigation stack.
Hence viewDidLoad will not get called. As your view controller is already in memory stack. So it will just make the view to reappear on windows and it will call viewWillAppear respectively.