I have 10 views with UINavigationController in hierarchy. Now when I want to go back from 10 to 9, and so on with back button, which method should I use?
popviewController
popToViewController
I have set a fixed value for all views. At application launch, I get that value. For that value I initialize rootviewController with use of UINavigationController. And my rootviewController is nothing but the first view and after that on next line, I'm pushing a particular view.
If you're pushing the views onto a UINavigationController, you don't need to explicitly set any method for the back button that the UINavigationController object manages, since it will pop the correct view when tapped. It's all automatic.
Related
So I've got a UITabBarController as a view in my app, the first tab of which is a UINavigationController. I have a button inside this view that pushes another, custom view onto the stack:
myViewController *vc = [[myViewController alloc] init];
[self pushViewController:myOtherView animated:YES];
The class myViewController has things that are supposed to happen inside of both -viewDidLoad and -viewDidAppear:(BOOL)animated, but if I hit my button right after the UITabBarController view appears, neither of those methods seem to be called. And even stranger, when I hit "Back", the view does not animate away, but rather the view underneath it in the stack just pops back into place.
However, if I go to another tab in the tab bar, then go back to the first tab, then hit my button again, my custom view controller animates in, -viewDidAppear:(BOOL)animated is called, and it animates out of view upon hitting "Back" like it should. Unfortunately, -viewDidLoad is never called.
I'm really trying to get away from using Interface Builder for everything; I want to create this view controller purely programatically, but these weird issues aren't helping. Can anyone think of a reason for this bizarre behavior?
Edit: Even if I create my view controller via IB, this behavior still occurs. What's the deal? Do I need to do something to the UITabBarController?
Edit #2: Here's how I want my views to bet set up:
UITabBarControler
Tab 1: UINavigationController
UIViewController to be pushed onto the stack
UIViewController to be pushed onto the stack
etc (possibly more UIViewControllers)
Tab 2: UIViewController
Tab 3: UINavigation Controller
UIViewController to be pushed onto the stack
UIViewController to be pushed onto the stack
You don't say what kind of object contains the code you posted but, if it's handling a button action, it's probably a custom view controller that's managed by your navigation controller. If that's true, then you'd want [self.navigationController pushViewController:myOtherView animated:YES];.
(If self is some other kind of object or self.navigationController is nil, then you would need to add some more details about your current view controller structure.)
I have an application with a UITabBarController at its top level. I track which tab a user is on and store it so that when they reopen the application they are on the tab they were on when it was closed. So there is no default tab when the app starts up.
I have a modal screen that shows first every time the app starts. It doesn't matter which tab was saved, the user is always presented with this view.
Where should this modal view be presented from? The logical thing would be to have the UITabBarController present it as it is the rootViewController, but Apple discourages subclassing UITabBarController. Another approach would be to have a UIViewController as the rootViewController that would handle the presentation, but Apple insist that UITabBarController should be the rootViewController.
So how should I deal with this?
If you start with a window-based application and first set your viewController as rootViewController and then, after you're done with this viewController, set the tabBarController as rootViewController, i think you don't have problems.
I have two UIViewControllers, vc1 and vc2.
I want to switch between them. But before loading the view of the new view controller, I want to destroy/release/remove (I'm not sure abt the correct word to use here) the previous viewcontroller.
For example, when I am switching to vc2 from vc1 ,I want to destroy vc1 completely, so that when I return to vc1 from vc2, vc1 will be loaded from scratch (i.e. viewDidLoad will be executed).
Which type of view switching should I opt for?
presentModal...
addSubview.
I am not using a navigation controller.
Currently I am using the presentModal... method, but when I use dismissModalViewcontroller on the newly presented view controller, it doesn't show up a new instance of the previous view controller. Instead, it shows the already running instance of it.
I want the viewDidLoad method of the previous view controller to run when I dismiss the newly presented view controller.
What exactly needs to happen in viewDidLoad?
You also have viewWillAppear available to you, so it could be that you could move the required functionality there and still use the modal presentation.
See this answer. You can do this with or without animation.
Animate change of view controllers without using navigation controller stack, subviews or modal controllers?
I have a navigationController, I push a new viewController onto it's stack, I have been trying to figure out a way to switch this ViewController with another viewController from within the first ViewController.
I have 3 almost identical views, depending on the user interaction I would like to be able to switch between these views within the same stack index i.e. without pushing or popping views on the navigationController.
So if view C has index 3 on the navigationController stack and the user taps a certain button in view C the C1 view replaces C on the stack and gets index 3.
I have been through the UINavigation Class and can't find a way around this.
If I popViewController from within the current viewController and the tries to pushViewController… well that can't be done as the viewController gets released when popping it. If I instead try to do pushViewController, well then I gets added on top of my current viewController.
I hope it makes sense and that someone can help me out:)
Thanks
You can assign an NSArray of controllers to the viewControllers property to alter the entire stack instantaneously.
Using a navigation based view hierarchy. I have a root view controller, and multiple view controllers that branch out from the same when a button is pressed. When a user presses the back button on the UINavigationBar, the current viewcontroller is popped and the display animates back to the rootviewcontroller.
The problem is, I want the viewcontrollers to UNLOAD whenever they are popped. Seems like they are not unloading because when I go back to them they are still in the state they were when they were popped.
How do I unload the viewcontrollers after navigating back to the rootviewcontroller?
-viewUnload is called after the application receives low-memory notification.
It is the default implementation of -didReceiveMemoryWarning that calls -viewUnload.
What you probably want to do is put what you want to do into -viewDidDisappear based on what you've described.
When you pop a viewcontroller from a navigationcontroller, there should be no more references to the viewcontroller left and the viewcontroller should be deallocated at that time. This should give you the results you expected. You can test if the viewcontroller is being deallocated by adding a break point in -dealloc method.
If dealloc does not get called, check if there is a retain cycle. Specifically check if a child object is retaining the viewcontroller.
in -viewDidDisappear why not [self release]; just need to make sure you have a lazy loader so it will load back when needed.