I have a root view open up on a view controller, however once there I am unable to push to new View Controllers. The actions were working whenever I would navigate to this page, but no longer do once I made it my root view. Here is the action I have, which is called but fails at pushing to the new view.
-(IBAction)pushToSettings:(id)sender{
NSLog(#"Problem");
SettingsView *viewController = [[SettingsView alloc] init];
[self.navigationController pushViewController:viewController animated:NO];
}
Is there anything wrong which is causing this action not to push to the new view?
The problem is that you are not in a navigation interface (i.e. this view controller is now not the child of a UINavigationController). There is thus no navigationController, so it is nil and nothing happens when you send the pushViewController message to it.
Related
There is a default calendar app.
It starts with the next view controller and back button is already there like there some other view controller was started before this one:
When you press back button you get the next view controller:
How did they do it?
In my app I need the same logic (to start a view controller with the latest or default category but users can press back button to select a different category)
If I were to do this, I would start by simply using pushViewController(animated:) to push the month view onto the navigation stack, with animated: false in the root view controller's viewWillAppear(animated:) method. The calendar would appear to the user already one level deep in the navigation stack.
So, the first controller is the year view, and then the month view is the second one pushed onto the stack, but it all happens before the user has seen any of the views. Simple, right?
Here are the docs for UINavigationController in case that helps.
I think what you want is to push the view controllers once at start. An easy way to do it is to sub-class UINavigationController and assign it to the root navigation controller in your storyboard. Then simply do the work in your sub-class' viewWillAppear method, as this will be called exactly once at startup.
Of course, you can also accomplish the same result by using a flag to only load the next view controller once if you put the push code in the first view controller's viewWillAppear.
#interface MyNavigationController : UINavigationController
#end
#implementation MyNavigationController
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
UIViewController *secondVC = [self.storyboard instantiateViewControllerWithIdentifier:#"secondVC"];
[self pushViewController:secondVC animated:NO];
}
#end
Please see the following attached image for more understanding.
The scenario is : I have five view controllers
Each view navigate to next viewController on push
Now the MidContainerViewController has got the Container which embeds the FirstViewController.
Bottom of MidContainerViewController is a static view which should not change while navigating further.
On navigation The FirstViewController should be of size equal to container
Also when I navigate to SecondViewController from FirstViewController, it should also be of size of Container.
Objective 1 : 'FirstViewController' and 'SecondViewController' should not take whole screen overlapping the bottomView image on MidContainerViewController.
Objective 2 : I must pop to root "View Controller" on last 'push' on SecondViewController.
Solutions :
1) Currently As I have embedding the root "View Controller" to navigationController. No problem with objective 2. It successfully navigates back to root. But can't achieve objective 1
2) If I embed the "First View Controller" too with navigationController the objective 1 is achieved but start facing problem for objective 2. It pop back till 'MidContainerViewController' only.
Any suggestion are highly appreciated.
Thanks,
Assuming your are manually handling push/pop events without using storyboard, I recommend you to not push the FirstViewController from MidContainerViewController. Add the next view controller as child view controller through following code:
FirstViewController *firstViewController = [[FirstViewController alloc] initWithNibName:#"FirstViewController" bundle:[NSBundle mainBundle]];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:firstViewController];
[self addChildViewController:navController];
[navController.view setFrame:CGRectMake(0.0f, 0.0f, _containerView.frame.size.width, _containerView.frame.size.height)];
[_containerView addSubview:navController.view];
[navController didMoveToParentViewController:self];
From the above code you'll achieve your first objective. In the above code, the FirstViewController gets initiated on its own separate navigation controller object, so it will have different navigation stack. So if you further push and pop from FirstViewController & SecondViewController, your view will not take the whole screen. But if you call popToRootViewController from last view controller, your root view controller would be FirstViewController in that specific container view.
To achieve second objective, you'll have to create a public property to contain reference of main navigation controller object in your AppDelegate class. Create your root view controller from that navigation controller object. In your last view controller, you'll then have to get reference of that navigation controller property from your AppDelagate class and then call popToRootViewController from that object.
i think you must present your root view controller from the secondView Controller rather that embedding to root view controller.
Thank you everyone.
The problem is solved and both the objectives are achieved.
I kept only one navigation controller as root view controller.
I created one customContainerViewController.
This class has instances of all the children it is supposed to show.
This class acts as delegate for each of its childViewController. Make customContainerViewController as deleagte of each childViewController.
I updated the chilren using delegation method and using UIView transition method in UIKit.
This worked for me.
In iOS 7 I got the last pushed view controller in this code:
id controller = [self.navigationController.viewControllers lastObject];
But same code in iOS 8 return another controller (root view controller for this navigation controller). How I can fix it?
I have the same problem currently while running tests and checking if the view controllers are correctly added to the navigation stack. I noticed, that by removing the push animation
navigationController.viewControllers
would return the correct view controller. I assume, in iOS8 you'll have to wait for the animation to finish until you can get the correct object out of the viewControllers-property.
You could just try with
[navigationController setViewControllers:array animated:NO]
I have an application that has a login page. It then moves to a navigation controller that has a collection view as its root view controller. When the app starts and there is only one item in the collection, I want to have the navigation controller automatically push to that item and allow the user to use 'back' to view the collection. This is the same behavior that is in 'Notes' from Apple.
The idea is to allow the user to immediately start to use the app and only 'discover' the need for the collection view after using the app for some time.
I am using IB, storyboards, and segues for my view transitions.
If I programmatically have the root view controller do a performSegue in its viewWillLoad: I get an error about causing a transition while a transition is still in process.
If I move the code calling performSegue into the didLoad, then the user sees a double transition.
A navigation controller usually manages the underlying stack itself. That is, you pass it an initial view controller, and then through segues or pushViewController:animated: the stack is altered. However, there is nothing stopping you from manually altering the stack. In prepareForSegue:sender:, you can check the number of items, and if it's 1, do something like this:
UIViewController *singleItemViewController = [self.storyboard instantiateViewControllerWithIdentifier:#"SingleItem"];
NSMutableArray *viewControllers = [sender.destinationViewController.viewControllers mutableCopy];
[viewControllers addObject:singleItemViewController];
sender.destinationViewController.viewControllers = viewControllers;
Now instead of starting at the first view controller of the stack, you start at the second one, with a back button to navigate back.
Actually, I found that the following worked the best for me.
if (/* reason to change back list*/) {
UIViewController * rootViewController = [[UIStoryboard storyboardWithName:#"Main" bundle:nil] instantiateViewControllerWithIdentifier:#"backViewController"];
NSArray * viewControllers = #[rootViewController, self];
[self.navigationController setViewControllers:viewControllers animated:NO];
}
setViewControllers seems to be the best way to manipulate the stack.
I have a view controller which contains a table view, and which is wrapped within a navigation controller, i.e. in the app delegate these two are created and set as:
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:self.myViewController];
self.window.rootViewController = navController;
If the user clicks on a row within a table then another view controller is created and pushed to the navigation controller's stack:
[self.navigationController pushViewController:webPageController animated:YES];
The webPageController loads and reads local files. If a file is missing I want to abort the loading of the webPageController and the displaying of its view and have the table view displayed.
How should I achieve this?
If the webPageController detects a problem I've tried experimenting with it calling various things such as:
[self.navigationController popViewControllerAnimated:YES];
or
[self.navigationController.navigationBar popNavigationItemAnimated:YES];
To pop itself off the navigation stack, however these aren't working, is it wrong for a navigation controller to attempt to pop itself like this? What is the canonical way of implementing this?
Thanks
That should be fine. Where are you calling popViewControllerAnimated:? If you're calling before viewDidAppear, you'll likely run into problems. ViewControllers need to finish the appearing and disappearing before they can make any kind of pop or push to their stack. If you do it before, you get really weird results. The most common symptom of this is it doesn't work. Often buttons inside it will get messed up as well.