I have two viewcontrollers. The first viewcontroller is collection view controller and i set self.navigationController?.hidesBarsOnSwipe = true in viewDidLoad().
When I push the second viewController from the visible cell of collectionView, the navigation bar is showing in the second viewController but if I scroll the collectionView cell and when push the navigation is not showing.
Can anyone tell me what the problem is?
scrolling is done via swipe gesture, so it triggers your code:
self.navigationController?.hidesBarsOnSwipe = true
because navigation controller is shared between all view controllers presented on top of it, it's properties (like hidden bar) preserves pushing / popping.
Common pattern is to change it's state in overrided lifecycle methods, eg:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.navigationController?.hidesBarsOnSwipe = false
self.navigationController?.setNavigationBarHidden(false, animated: true)
}
and reverting those state in viewWillDisappear
When this property is set to true, an upward swipe hides the navigation bar and toolbar. A downward swipe shows both bars again. If the toolbar does not have any items, it remains visible even after a swipe. The default value of this property is false. (get it from apple)
See the doc https://developer.apple.com/documentation/uikit/uinavigationcontroller/1621883-hidesbarsonswipe
It means when you swipe up it will hide and when swipe down it will shown. That's the reason.
To fix it you can add following code to the other controller
[self.navigationController setNavigationBarHidden:NO animated:YES];
Don't get much insight what exactly you implemented, but try to unhide navigation bar in second view controller.
Add below code in viewDidLoad method of second View controller.
self.navigationController?.isNavigationBarHidden = false
Put this self.navigationController?.hidesBarsOnSwipe = false and this self.navigationController?.setNavigationBarHidden(false, animated: true) in your second view controller.
You might want to move your self.navigationController?.hidesBarsOnSwipe = true from viewDidLoad to viewWillAppear in your first view controller.
Related
I have view controller which navigation bar is hidden.
navigationController?.isNavigationBarHidden = true
I push another controller when tap on a button.
navigationController?.pushViewController(qrGenerateVC, animated: true)
In the second view controller the navigation bar is not hidden.
In other situations when I swipe back the second navigation bar hides smoothly but in this situation It disappear when I start swiping back. so it makes the view look not good.
This is similar to this question which does not have answer. And the view is similar too.
Before swipe screenShot
After swipe screenShot
These images are from that question. but similar thing happens here.
Set this in your second view controller
override func viewWillAppear(_ animated: Bool) {
self.navigationController?.isNavigationBarHidden = false
}
Consider a storyboard where we have UITabBarController, in it any UIViewController(lets call it VC) embedded in a UINavigationController. We want VC to have a BarButtonItems on its navigation bar. This storyboard is presented by push segue from another storyboard (having another navigation controller).
Everything looks OK in XCode, but navigation bar does not change in VC at the runtime. However when I change presenting this storyboard from push to modal, everything seems to be fine. IMHO it is because of embedding the navigation controller but I do not see any reason why it is not working. Any idea how to fix it legally (presenting by push) and without any pain would be helpful.
Thanks in advance
So I think you will have to employ some code to fix your issue but not much. I built a test project to test this and will attach images along with code.
First if I understand you correctly you have a navigationController push the new storyboard in question. See attached image.
I named the storyboard being pushed because that is what is happening. Then in my storyboard named Push here is the setup.
In the first view controller of the tabbarcontroller I added the below code. Obviously this hides the navigation controller that pushed us here. If you then visit controller number 2 our new navigation controller and items show. If hiding the navigation controller in the tabbarcontroller view controller 1 is not what you want to do then. continue reading.
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
//or to unhide from returning the opposite ->self.parent?.navigationController?.isNavigationBarHidden = true
self.parent?.navigationController?.isNavigationBarHidden = true
}
If you did not want to hide the navigation controller in the first view controller but when visiting controller 2 you want to see your items then add this to your viewWillAppear and in the first controller in viewWillAppear change the code from true to false.
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
// Do any additional setup after loading the view, typically from a nib.
self.parent?.navigationController?.isNavigationBarHidden = true
}
This hides the parent navigation controller as basically that was covering up your navigation controller in your example. So above hides the parent navigation controller. This is also why presenting modally worked. Your navigation controller was hidden from the start. Hope this helps.
**Edit
If you want the navigation controller in tab 2 view controller but you want to keep the parent in tab one to be able to go back with the back button you can set this in viewWillAppear instead so it would look like this in view controller 1.
//tabcontroller vc 1
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.navigationController?.isNavigationBarHidden = false
}
And in tabcontroller view controller 2 with the item in the bar you could do this.
//tabbarcontroller vc 2 with own navigationcontroller
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.parent?.navigationController?.isNavigationBarHidden = true
}
Finally if you want the back button visible in both controllers but want different right buttons do it programmatically in viewWillAppear
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.tabBarController?.navigationItem.setRightBarButton(UIBarButtonItem(barButtonSystemItem: .edit, target: self, action: #selector(FirstViewController.editSomthing)), animated: true)
}
And if you want to remove it in the other controller
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.tabBarController?.navigationItem.rightBarButtonItem = nil;
}
In Both of the above examples directly above this, we are keeping the parent navigation controller so you would not need to embed your view controllers of the tab controller inside uinavigation controller.
You could also use a combo of the above code if you want the hide/show parent navigation controller in viewWillAppear as well. Some of this is dependent on the view hierarchy you choose now and in the future.
I have a View Controller which is the 2nd View Controller and need a navigation bar. The 1st one is a controller which doesn't need a Nav Bar and 3rd View Controller need a navigation bar.
As per stacks 3rd view controller will be no top of stack.
I have implemented these methods in 2nd View Controller:
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
if self.navigationController?.navigationBarHidden == true{
self.navigationController?.navigationBarHidden = false
}
self.navigationItem.backBarButtonItem = UIBarButtonItem(title: "", style: .Plain, target: nil, action: nil)
self.navigationController?.navigationBar.tintColor = Quikr_Util.colorWithHexString("#0083cb")
}
override func viewWillDisappear(animated: Bool) {
super.viewWillDisappear(animated)
if self.navigationController?.navigationBarHidden == false{
self.navigationController?.navigationBarHidden = true
}
}
The things were working fine if a use a back bar button to go back from 3rd to 2nd View Controller.
Things got messy when I started to slide from one View Controller to another for example, when I slide half and then release.
It means sliding from 3rd to 2nd but release in between so it goes to 3rd View Controller rather than second .
What may be the best way to hide and unhide view navigation bars .
Secondly, how do sliding works , which functions will get called when sliding happens?
For your first question
To hide and show the Navigation Controller, in 2nd and 3rd View Controllers, You can use:
Hide:
navigationController?.setNavigationBarHidden(true, animated: false)
Show:
navigationController?.setNavigationBarHidden(false, animated: false)
There is not really a need to check if it is hidden or not.
For the second question, you can use UIGestureRecognizer
Edit:
Just to be clear, instead of hiding and showing the in the same file, hide and show in viewDidAppear() in needed swift files
I have a parent TableViewController and a child ViewController all within the context of a navigation controller. What I want to happen is for the table view controller to NEVER show the nav bar, and for the view controller to ALWAYS show the nav bar. I hide and show the nav bar within the viewWillAppear func of each subclass, like this:
table view controller:
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(true);
navigationController?.navigationBar.hidden = true
UIApplication.sharedApplication().statusBarHidden=true
}
view controller:
override func viewWillAppear(animated: Bool) {
self.navigationController?.navigationBarHidden = false
}
This works for the first navigation. When I launch the app, the parent table view controller hides the nav bar, and when I select the first cell, the child view controller dutifully displays the nav bar. However, when I touch 'Back' on the nav bar, and then select the cell again, the view controller is no longer displaying the nav bar.
Is there a better way to do this?
Update - as requested attaching screenshots of XIB and Storyboard. Note that there is no XIB for the parent TableViewController. I am not confident that these screenshot will provide much insight. Especially that of the storyboard. Unfortunately, Xcode only has 2 zoom levels:
1. Too zoomed in to be useful
2. Too zoomed out to be useful
Nonetheless, here you have them:
That should work fine: When your ViewController will appear, the code should get executed every time. Try with an "print" to test if that happens.
First View Controller
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(true)
print("viewWillLoad - Table View")
self.navigationController?.navigationBarHidden = false
}
Second View Controller
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(true)
print("viewWillLoad - Detail View")
self.navigationController?.navigationBarHidden = true
}
Ill use that in some applications too.
I have the hidesBottomBarWhenPushed = true set for one of my UIViewController's (call it ViewControllerA) that is pushed onto my UINavigationController stack. I also opt to show the bottomBar when I push a new ViewController ontop of ViewControllerA. Therefore I have:
class ViewControllerA: UIViewController {
override func viewWillDisappear(animated: Bool) {
self.hidesBottomBarWhenPushed = false
}
override func viewWillAppear(animated: Bool) {
self.hidesBottomBarWhenPushed = true
}
This all works fine.
When I push ViewControllerA, the bottom bar hides.
When I push any other ViewController, the bottom bar shows.
However, when I am traveling backwards in the navigation stack (aka hitting the UIBarButtonItemBack button), I cannot get the bottomBar to hide when I pop the navigation stack to reveal ViewControllerA.
What am I missing? Thanks!
Got it! Here's what worked:
class ViewControllerCustom: UIViewController {
init() {
self.hidesBottomBarWhenPushed = true
}
override func viewDidAppear(animated: Bool) {
self.hidesBottomBarWhenPushed = false
}
}
And then in every UIViewController's custom implementation of BarButtonItemBack pressed I check to see if the previous view controller (that will be popped to needs to hide the tab bar). Granted I abstracted this out into a general function so I didn't need to repeat code, but here's the concept. Thanks for the help figuring this out though!
func barButtonItemBackPressed(button: UIButton) {
var viewControllers = self.navigationController!.viewControllers as! [UIViewController]
if ((viewControllers[viewControllers.count - 2]).isKindOfClass(ViewControllerCustom.self)) {
(viewControllers[viewControllers.count - 2] as! ViewControllerCustom).hidesBottomBarWhenPushed = true
}
self.navigationController?.popViewControllerAnimated(true)
}
I believe the intended use of this property is to hide the bar when pushed. So, when your view controller appears after the top-most one is popped, it wasn't pushed on the stack, so it doesn't change the tab bar's appearance.
This leaves you with two options:
1) Keep the bottom bar for all view controllers. When text is being entered, the keyboard covers the bottom bar.
2) Hide the bottom bar for View Controller A, as well as any other view controller that is pushed on top of A.