I have a UINavigationController in which I push / display several other UIViewControllers. I would like a specific title and button (a Cancel button to be precise, which appears on the right-hand side) to always appear in the UINavigationController's UINavigationBar regardless of the view controller being displayed within the navigation controller. At the moment I have set the .title and .navigationItem.rightBarButtonItem of each individual view controller to be the same, but this seems like (a) a lot of wasted effort; and (b) when a new view controller is pushed onto the stack there is a brief animation where the title and button can be seen animating out and then back in - obviously not desirable since I want to give the appearance that those items are static and never change.
Any suggestions would be greatly appreciated.
Try to set all you need in UINavigationController and then in viewWillAppear of your UIViewControllers subclasses paste:
[self.navigationItem setLeftBarButtonItem:self.navigationController.navigationItem.leftBarButtonItem];
[self.navigationItem setRightBarButtonItem:self.navigationController.navigationItem.rightBarButtonItem];
Related
In my iPhone project, I have a navigation view controller. In each view that is loaded by this controller, I am setting buttons in the UINavigationBar that are doing different things for each view.
However, I want to have the .rightBarButtonItem do exactly the same thing each time (namely, pop up a UIActionSheet). How can I centralize this code and not have to put it in every view controller?
I tried subclassing UINavigationController and setting the .rightBarButtonItem in this subclass' viewDidLoad. However, no button is displayed then. (But when I put the same code in a view controller loaded by the navigation controller, the button is displayed and works fine).
The code I am using to set the rightBarButtonItem is:
self.navigationItem.rightBarButtonItem = ...
Subclass all the UIViewControllers that are pushed onto that UINavigationController and add the same viewDidLoad code.
So before I push a new viewController onto the stack in a certain view, I set the navigationBar to hidden I notice that it disappears before the next screen gets pushed and the slide animation happens (because I need a UIToolbar at the top).
So question #1: is there a way to push a new view controller and setting the navigationbar to hidden, and not getting the hide animation until after the new view controller is on screen. it looks funny that the navigation bar hides then pushes the new view controller.
Once the new view controller is present, when I pop it off, I set the navigation bar back
[self.navigationController.navigationBar setHidden:NO];
But when it is popped, the navigationbar is not back any more. Is it because this navigationBar is for the current navigationController and not the new one that is being presented after the pop? (question #2)
Question 3: Realizing it isn't showing my navigationBar, in the viewController that gets presented after the pop, in its viewDidAppear, I added
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[self.navigationController.navigationBar setHidden:NO];
}
which shows the navigationBar, but the view size is incorrect since it seems like once the navigation bar was hidden, the rest of the view took up the empty space, and then the navigationBar is on top of the content. Is there anything I can do about this? Or am I approaching it incorrectly with push and pop?(question #3).
Thanks!
I was running into the very same problem (only in reverse: I was starting from a NavigationBar being hidden and pushing a view where I wanted the NavigationBar visible), and there's actually an extremely easy fix.
Simply replace your calls:
[self.navigationController.navigationBar setHidden:NO];
with
[[self navigationController] setNavigationBarHidden:NO animated:YES];
In my code, I call these statements in the - (void)viewWillAppear:(BOOL)animated methods of each respective View Controller.
I just tried this solution in the order you are using (visible, then hidden), and it seems to work just as well.
Interesting issue. You could try changing the hidden property in viewWillAppear and viewWillDisappear, but it seems like that might not give the desired results either.
Can you present the view controller modally instead of making the navigation bar disappear? If it's the last view controller on the stack, that would be possible. It might also make more sense to the user to see a view controller presented differently. This might indicate to the user that navigating away from this view controller is no longer done with the Back Button. It could be more reasonable than having the navigation bar just disappear.
If you still wanted the view controller to slide in from the right, I don't think it can be done with a modal view controller. But, you could do that by animating a view that fills the screen. (You just add the view with a frame that has origin.x equal to the width of the screen. Then, in the animation, you change origin.x to 0.0. Let me know if you need more detail on this.)
However, I would recommend presenting the view controller in a different manner from the way a view is generally presented by a navigation controller. Because, essentially, you are no longer letting the user navigate away from this view as he/she generally would from within a navigation controller. (So, my response to question #3 would be 'yes'.)
When I push a view via my app's navigationController, it automatically puts a back button on the left side of the navigationBar. Is there any way I can just remove this? (I want to put my own buttons on the screen that will allow the view to be popped).
From the comments, you can hide the back button for a viewController by using its navigationItem property. (which is the UINavigationItem corresponding to that viewController in the stack of the navigationController. its how you control what shows up on the bar for specific view controllers (see Apple Doc here)).
To answer your question, set the navigationItem's hidesBackButton property to YES. Something like this probably called in your viewControllers viewDidLoad: or similar method.
myViewController.navigationItem.hidesBackButton = YES;
have you try with self.navigationItem.hidesBackButton=YES;?
If I wanted to do it, I'd hide the Navigation bar on push (non animated hide), add a toolbar, and add any custom stuff I want to the toolbar.
on popping the view controller, make sure to unhide the navigation bar. It'll work
I've come across this twice now.
Sometimes using the following line of code:
[self.navigationController presentModalViewController:aViewController animated:YES];
displays the view, but the navigation bar is then hidden.
I can write:
[self.navigationController setNavigationBarHidden:NO];
to my hearts content, everywhere I can think of with no effect.
Has anyone ran into this?
Am I doing something silly?
No, I ran into this as well. The problem is that when you present a modal view controller with a UIViewController based class, it does not extend the calling navigation controller's nav bar onto the modal. The modal view covers the entire screen. What I ended up doing to solve the problem was to create a UINavigationController and push the UIViewController based class onto it, and then do presentModalViewController to the navigation controller's instance.
like:
UIViewController *vc = [[UIViewController alloc] init];
UINavigationController *cntrol = [[UINavigationController alloc] initWithRootViewController:vc];
[self presentModalViewController:cntrol animated:YES];
[cntrol release];
That allowed me to have a nav bar at the top.
I am not sure if that will help in your particular case, the only other thing I would suggest is to replicate the behavior of the modal with a UIAnimation that stops 44px below the top of the phone. That would keep the original navigation bar visible.
#HeatMiser shows a great way to get around the "bug" surrounding the inability to display items on the nav bar. I'm not sure, however, if this is strictly a bug in Presentation, since modal operations ought to trump the underlying view's interface theme. Having the modal operation's theme mimic the underlying UI theme is fine, but wrapping the true modal view with a navigation view feels wrong to me (extra view object just to get a little more behavior).
Instead, the following worked for me and gives the same behavior as "New Message" does in the Mail program (on the iPhone).
In IB, place a UIToolBar at the top of the modal screen (mimicking the navigation bar) with "Cancel" and "Save" UIBarButtonItem's and a Flexible Space Bar Button Item in between to get the buttons to align left and right. Then, add a UILabel centered over the UIToolBar (The Font Helvetica, Bold, Size 18 appears to match the Navigation Bar Title). Connect the buttons to IBAction's on the modal's UIViewController, and you're done.
If there is a navigation controller active, then you should just use
[self.navigationController pushViewControllerAnimated:how];
to slide another view controller in, while giving yourself and the user into a consistent user interface complete with 'automatic' back button support.
Once a navigation controller is in use, presenting a modal view controller should only be done to enlarge the usable area on the screen. And then, you should really use a fancy animation to let the user know that you are stepping away from the "task" or "steps" that the navigation controller was embodying.
Maybe this is obvious, but once you're done with the modal view and want to dismiss it, you should do something like this in your modal vc:
[parentController dismissModalViewControllerAnimated:YES];
Where parentController is a reference to the vc from where you are presenting the modal view.
As titled. I need a way to display the arrow buttom on UINavigationbar without actually pushing a controller. The reason why I can't push a controller is because I need to keep the keyboard displayed while transitioning.
So to clarify: I start with a modal view controller (where there's nothing on the top left bar) like this -
(source: iphonefaq.org)
Then transition the top bar to one that looks like this -
(source: gizmodo.com)
Sure, you can do this pretty easily. Just set the leftBarButtonItem of your self.navigationItem to be a back button.
It looks like you can do this by getting the UINavigationItem for the current screen. You can get it from the topItem property of the UINavigationBar.
Once you have the UINavigationItem that represents your current title are you should be able to experiment with the backBarButtonItem property, then call setHidesBackButton:animated: to show the back button.
You can*not* dynamically change the backbutton on the UINavigationItem instance that belongs to the UIViewController instance that is currently being displayed. The backbutton that you will see displayed is the last one that was set before the UIViewController instance (and its UINAvigationItem) was pushed.
BUT, you can show/hide the backbutton. So how about setting the correct backbutton before the UIViewController instance is pushed and hiding it (viewControllerInstance.navigationItem.hidesBackButton = YES;"). And then setting "viewControllerInstance.navigationItem.hidesBackButton = NO;" when you want to display the back button.
You can obviously dynamically change the UINavigationItems and their backbuttons on a UINavigationBar that you create yourself (i.e. one that does not belong to a UINavigationController).