I'm running into problems reconfiguring the UINavigationBar on iOS 7 and 8 when transitioning between views.
My application currently contains the following UIViewController flow:
VC1 --> VC2 --> VC3
In this flow
VC1 is the home screen and has an opaque UINavigationBar
VC2 has a translucent UINavigationBar
VC3 goes back to having an opaque UINavigationBar
The problem I've been running into is that the transitions between these views are all very sloppy looking. To start with I tried the following:
in VC2
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
// configure appearance
[self.navigationController.navigationBar configureTranslucentAppearance];
}
And in VC1 and VC3
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
// configure appearance
[self.navigationController.navigationBar restoreDefaultAppearance];
}
Here are the implementations of the two helper functions listed above:
- (void)restoreDefaultAppearance {
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
[self setTitleTextAttributes:#{NSForegroundColorAttributeName: [UIColor JTTextNavBar]}];
[self setTintColor:[UIColor JTTextNavBar]];
[self setBarTintColor:[UIColor JTBackgroundNavBarWithAlpha:1.0]];
[self setBackgroundImage:nil forBarMetrics:UIBarMetricsDefault];
[self setBackgroundColor:[UIColor JTBackgroundNavBarWithAlpha:1.0]];
[self setShadowImage:[UIImage navigationBarShadowImage]];
[self setTranslucent:NO];
}
- (void)configureTranslucentAppearance {
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
[self setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
[self setBackgroundColor:[UIColor clearColor]];
[self setShadowImage:[UIImage new]];
[self setTranslucent:YES];
}
This is the most basic way of handling this transition. It has the following visual artefacts:
When going from VC1 --> VC2 the moment you begin the transition the navigation bar turns black. The animation completes normally
When going from VC2 --> VC1 the nav bar instantly changes to the application default colour before the segue has time to complete.
When going from VC2 --> VC3 the navigation bar instantly goes from translucent to the app nav bar color and then menu items and VC body animate in.
When going from VC3 --> VC2 the nav bar instantly turns black and remains this way until the segue is complete.
None of these transitions look good at all. Ideally I would like the views to transition smoothly along with their new UINavigationBar but the only way I've seen to do this successfully is to manually add a toolbar to each xib.
Any suggestions? Apologies if this description is confusing :(
Edit: Added cropped images of the UINavigationBar and top portion of UIViewController for each of the listed transitions.
I finally found a decent solution!
There doesn't appear to be a proper way to smoothly transition from an opaque to transparent UINavigationBar BUT you can transition smoothly from a view controller with a visible status bar to one that has a hidden status bar.
This opens up a possible workaround which is to add the following in the viewWillAppear of VC2 from above:
[self.navigationController setNavigationBarHidden:YES animated:YES];
Once you have that, manually add a UINavigationBar to your xib and configure it to be transparent (and add all necessary UIBarButtonItem and views).
If everything is hooked up properly transitioning from VC1 to VC2 will hide the UINavigationBar at the same speed as the view transition and VC2 will show up with it's embedded UINavigationBar
Note: To make this work properly you'll have to make sure that in the viewWillAppear of View Controllers that can be accessed from VC2 you reset the UINavigationBar to be visible (if necessary) via:
[self.navigationController setNavigationBarHidden:NO animated:YES];
TL;DR - manually add a UINavigationBar to your transparent nav bar view controller and in its viewWillAppear hide the default one via setNavigationBarHidden:animated:
The black color you're seeing is the background color of the UINavigationController's view. One way to minimize seeing it is to manipulate the background color of that view to the color of the outgoing / incoming view controller's view. This works well if you're working with solid colors. Another approach is to extend your views behind the opaque navigation bar using UIViewController.extendedLayoutIncludesOpaqueBars = YES;
Set the UIWindow background color to your Navigation bar's tintColor.
always use Translucent, plus add an uiview with a color below it and animate it's alpha?
I've struggled with a nearly identical problem. There really aren't any smooth transitions using either a nav bar or toolbar as a blur. The best option that I've found* is to make an image out of the view and then use that image for the transition. Especially if you just need it for transitions, it's just about the cheapest option that still provides a great UI/UX.
*The one caveat is that some of the UI effects in a nav bar and toolbar don't show up when you take a snapshot, screenshot, or rasterize a UIView as an image. This is negligible if used for a transition.
You can create your own navigation bar using just a UIView and that way you have complete control over its appearance, layout, fading etc.
I gave up using UINavigationBar a while ago as it can be a pain to work with, as you are discovering, and now I never ever use it.
I have a root view controller which has a UIView which represents the navigation bar. If I want to do something like add a back button, change the color, show the navigation bar or hide it, change the transparency, etc. that is all controlled by the RVC and other view controllers call methods on the RVC to change the navigation bar depending upon their appearance requirements.
The RVC has a container view which is the full size of the controller view and the other view controllers get loaded into that.
A little bit of configuration to get everything set up, but once done its a structure that can be used in every project that uses a navigation bar very quickly.
So I struggled with this too.
Unfortunately I didn't have any success adding my own navigation bar via the storyboard. Instead, (and I warn you this is hacky) I add a view in the ViewController with the opaque navigation bar that has a negative margin and extends under the navigation bar.
When the ViewController with the transparent navigation bar is pushed the bar then immediately becomes transparent but due to the identically coloured view I have place directly behind it the change isn't noticeable. Et voila.
The code I have is pretty basic and written in C# (Xamarin) but for reasons of completeness....
var backing = new UIView(new CGRect(0, -68, this.View.Frame.Width, 64f));
backing.BackgroundColor = UIColor.Green;
this.View.AddSubview(backing);
Change background color work for me
window?.backgroundColor = Color.red.toUIColor()
I have one more solution..for the ones who are now refactoring the project and cant add navigation bar everywhere.. This is not a perfect solution just like #alexgophermix one. But its not bad either:
let transition = CATransition()
transition.duration = 0.6
transition.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionLinear)
transition.type = kCATransitionFade
navigationController?.navigationBar.shadowImage = UIImage()
navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
navigationController?.navigationBar.isTranslucent = true
navigationController?.navigationBar.layer.add(transition, forKey: nil)
navigationController?.view.backgroundColor = .clear
I am setting my nav bar in viewDidLoad() so this works everywhere and gives a slight different transition. In my case I was setting clear backgrounds somewhere and rest a gradient image. So this small change goes well for everywhere. This transition is not much noticeable but neither looks bad :)
In my case, the black I was seeing was the navbar's background image. Instead of setting it to nil, I set it to match the background color of the view behind the transparent navbar inside viewWillAppear:
let image = UIImage(color: .white)
navigationController?.navigationBar.setBackgroundImage(image, for: .default)
Then, inside willMove and viewWillDisappear I reverted it back to the original color.
YPNavigationBarTransition is a configureable framework animating navigation bars.
YPNavigationBarTransition uses two fake navigationbars (UIToolBar indeed) to simulate bar transitions while making the real navigationbar transparent.
Subclass your own UINavigationController and embed transitioncenter in it like YPNavigationController
Implement YPNavigationBarProtocol for your content controllers respectively.
Done.
A complete demo is include in the repo, checkout it for more details.
I have this ViewController #1 which is the root view controller of a navigation controller and has
self.navigationController.navigationBarHidden = YES;
ViewController #1 tells its navigation controller to push ViewController #2, which has
self.navigationController.navigationBarHidden = NO;
When I want to go back from ViewController #2 to ViewController #1 by swiping from the left side of the screen, I see my views as the screenshot I attached here. This is captured as I move my finger to the right, so as I keep swiping to the right, the black area on the top right gets smaller and smaller until ViewController #1 covers all the screen area.
I'm guessing that this is caused by the hidden/visible navigation bar difference between the two view controllers.
I'd like to learn if it's possible to get rid of this black area.
As discussed with HoanNguyen, I had put my code to hide/show the navigation bar on viewWillAppear/Disappear but finally I figured out that the trick was to set the values animated. Weird, but this solved my problem and the black area is now gone:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[self.navigationController setNavigationBarHidden:self.shouldHideNavBar animated:animated];
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[self.navigationController setNavigationBarHidden:!self.shouldHideNavBar animated:animated];
}
You should put your code set hidden/shown navigation in viewWillAppear or viewDidAppear.
I currently have two view controllers, a CameraViewController that uses the imagePicker to take photos, and a PhotoInboxViewController that shows all the photo messages a person has received. PhotoInboxViewController, as well as my root view controller, is a Tab Bar Controller.
When I present the imagePicker in CameraViewController , as well as the image preview screen that follows it, I disable the TabBar by setting self.tabBarController.tabBar.hidden = YES. My issue is, when PhotoInboxViewController is then shown again (for example, if the user cancels taking a photo), I would want the Tab Bar to be shown again. In my viewWillAppear method in I have the following:
//In PhotoInboxViewController
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
if ([[[self tabBarController] tabBar] isHidden]){
self.tabBarController.tabBar.hidden = NO;
}
}
In debugging, I see that the if statement is indeed evaluated as tabBar as isHidden, and therefore the next line is executed as well. However, my Tab Bar remains hidden.
What am I doing incorrectly? Your help is appreciated - thanks!
You shouldn't need to hide the tab bar. When presenting modally you should present from the full screen / root view controller. In this case the tab bar controller, not the view controller 'in' one of the tabs. This allows the presentation to work properly without any strange side effects.
my app is structured as follow: UITabBarController > UINavigationController > ViewControllerOne > ViewControllerTwo.
the UINavigationBar has at the bottom the tab bar, now when the user navigates into the second view controller, i want to be able to hide the tab bar and replace is with a tool bar. i tried this code:
[self.navigationController.tabBarController.tabBar setHidden:YES];
[self.navigationController.toolbar setHidden:NO];
when i run the app the tab bar is hidden but the toolbar doesn't appear. plus, since the last VC is a table view controller, when i scroll through the cells there is a white gap between the table and the bottom of the view. how can i fix that?
That won't work because when you hide the tab bar like that the subviews won't be adjusted properly (that's why you get the white space). You'll have to use
self.hidesBottomBarWhenPushed = YES;
In your init method or awakeFromNib... and then
[self.navigationController setToolbarHidden:NO animated:YES];
In the viewDidLoad for example.
That way the tab bar controller's view is going to layout correctly it's subviews when you hide the tab bar. Just remember to call self.hidesBottomBarWhenPushed = NO; in your first view controller otherwise the tab bar is still going to be hidden when the second view controller is popped from the navigation stack.
Try to assigning toolbar with appropriate frame and adding it to self.tabBarController.view
I have almost done this in all the application but I have 3 views stacked in navigationController and I need to jump from the third view to the first view.
As I understand I can do this via viewWillDisappear only. But if I try this "jump" I will get the navigationController panel from the second View which with a navigation buttons which cause exceptions/errors.
P.S. Do not advice me to make leftBarButtonitem looking like backBarButtonItem. It is too difficult and I don't know where to find an appropriate image for it.
To my knowledge, you have no choice but to provide your own UIBarButtonItem. You are not permitted from interrupting how UINavigationController works by default. That is, you cannot override the behavior of the back button. You must provide a custom bar button item and set it as the navigation item's left bar button item.
(As a side note, the sort of behavior you're looking for may be an indication of a poor navigation pattern. Back buttons should almost always back out of a navigation hierarchy sequentially.)
Let's say in navigation order your views stacked like top -> 3 -> 2 -> 1 . When you are in this position you can have a flag in your application delegate that shows you will doublePop when backButton pressed as below: ( You are doing this whenever third view appears in the order you mentioned)
MyApplicationDelegate * del = [[UIApplication sharedApplication]delegate];
del.doublePopEnabled = YES;
[del release];
In view 2 :
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
MyApplicationDelegate * del = [[UIApplication sharedApplication]delegate];
if(del.doublePopEnabled){
//Asssuming you have a reference to your navigationController in your view 2
del.doublePopEnabled = NO;
[del.release]
//Use animated as no if you don't want user to see doublePopping.
self.navigationController popViewControllerAnimated:NO];
}
}
Hope it helps.