I have TabBar with 2 tabs. At some point, from either of the 2 tabs, I want to add a view that is visible on both tab views but behind the TabBar.
So I thought, insert a subview into the TabBarController but below the TabBar.
This works fine in principle and I have the view behind the TabBar but now covering my 2 tabs as I wanted. However, it doesn't actually load. Just its background loads and only viewDidLoad() is called, not viewWillAppear() or any others.
I have also tried calling addChildViewController(myVC) on the TabBarController which has no effect, and also manually calling viewWillAppear() on the view controller I add which also has no effect (and I'm also dubious about whether manually calling viewWillAppear() is permitted or not?).
Is what I'm trying to do possible? What am I missing? Or should I be attempting this some other way?
For some reason, when inserting a subview into a UITabBarController behind it's UITabBar, although the view is visible to the user, the system itself seems to think it is not and so although viewDidLoad() is called, viewDidAppear() and subsequent methods are not.
However, adding a subview above the UITabBar seems to work fine. So I solved this by adding my own new UITabBar as a subview to the UITabBarController (set up basically exactly as the default one would be) and then removing the UITabBarController's default UITabBar.
Then when later inserting my view into the UITabBarController, I insert it as I was doing originally but instead below/behind my custom UITabBar and it seems to load fine.
There is no need to remove and recreate the tabBar. What you need to do is after you insert your custom view, you can then bring the tabBar to the front again.
//bring the tabBar to the front after inserting new view
self.view.bringSubview(toFront: self.tabBar)
This would be a good way:
Add the function below and call it in viewDidLoad of your initial VC. It unwraps your tab bar controller instance (which is optional), and then inserts the view you always want visible just below the tab bar.
private func setupAlwaysVisibleView() {
guard let tabBarController = self.tabBarController else { return }
tabBarController.view.insertSubview(alwaysVisibleView, belowSubview: tabBarController.tabBar)
}
Avoid using optionals for tabBarController or removing current tabBar. Simple add your view below tabBar view. Swift 5, XCode 11.
class TabBarController: UITabBarController {
#IBOutlet var instructionsView: UIView!
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
self.view.insertSubview(instructionsView, belowSubview: self.tabBar)
}
}
you can also do this inside the init() method for your UITabViewController:
view.insertSubview(alwaysVisibleView, belowSubview: self.tabBar)
no need to dispatch to another method if you are using a subclass of UITabViewController.
Related
I want to change UIBarButton's color in the navigationBar. To achieve this, in viewDidLoad: I put this line:
navigationController?.navigationBar.tintColor = .white
Everything works fine until I started to notice something strange. That UIBarButton is used to dismiss the UIViewController. When it is pressed, I just dismiss the viewController. But, if I present it (viewController) again, the color of the UIBarButton is not white, it gets tintColor of the application.
After doing some debugging, I noticed that viewDidLoad: is not called again after the viewController is just dismissed and presented again. The reason why my UIBarButton has a different color is because I change its color in viewDidLoad:. When viewDidLoad: is not called, of course, color is not changed.
It was an interesting discovery for me the fact that iOS doesn't call viewDidLoad: for UIViewController that was presented already. Possibly, it is due to the optimisation, because it is not efficient to draw the whole UI every time.
My solution to this problem can be to change color, not in viewDidLoad:, but in viewDidAppear:. But, is it right approach to solve a problem? And why viewDidLoad: is not called in the above situation?
It looks like you create and store you view controller, but present it wrapped in UINavigationController:
let controller = YourModalViewController()
...
func presentMyModal() {
present(UINavigationController(rootViewController: controller))
}
In this case your viewDidLoad method will be called just once and you'll have visual bug. If you want to leave styling code of your modal inside it's file you can create instance func which will return this controller wrapped and styled.
extension YourModalViewController {
func wrappedInNC() -> UINavigationController {
let nc = UINavigationController(rootViewController: controller)
// Styling code.
return nc
}
}
An UITableViewController pretty much takes up the entire view. I need a way to limit its height, width and add some shadows etc. For a clear explanation, I won't show the UITableViewController's contents.
Without the use of a storyboard, I subviewed the UITableViewController:
// In another UIViewController
let otherController = OtherController() // A subclass of UITableViewController
let otherControllerView = otherController.view
someView.addSubView(otherControllerView)
[...] // bunch of constraints
Notes:
In AppDelegate, if I set the rootController as OtherController(), everything works as it should. If I change it back to SomeView(), I see my modified tableView. If I should click it, it disappears.
This was the only thing that came close to my issue but sadly, I could not understand the answers provided as nothing made any sense to me.
I need to understand, why it disappears when touched etc.
view.bringSubviewToFront(...) proved futile. I'm gessing that a tableView should be rendered in its own controller and not in another view?
So just to answer this question, indeed you got two options. One is the best way, as suggested by Rakesha. Just use UITableView. Add it as a subview. Done.
And in the future, if you really want any controller to be added onto any UIView, remember you need to add that controller as a child. For example, in your case:
The controller of the view that will hold your UITableViewController will add such UITableViewController as a child.
self.addChild(yourUITableViewController)
self.whatEverViewContainer.addSubview(yourUITableViewController.view)
// Take note of the view of your tableViewController above^.
// Then setup the constraints of your yourUITableViewController.view below.
I hope this helps!
You must add the instance of UITableViewController's subclass as child view controller of the other view controller. You need to ensure few points in order to make it work. The points are as listed below:
Create the instance of your TableViewController
Add it as a child view controller of the other view controller
Add its view as a subview of the desired view (you may do these steps in viewDidLaod since they need to be done only once)
Keeping in mind the view cycle of a view controller. You must keep a weak reference of the child view controller aka TableViewController to adjust its view frame after the parent view controller has laid its subviews.
Code here:
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let vc = TableViewController()
addChildViewController(vc)
view.addSubview(vc.view)
vc.didMove(toParentViewController: self)
childVC = vc
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
childVC?.view.frame = view.frame
}
I've added a custom UIView to my base UITabBarController. I start by hiding the default tabBar. The viewdidload looks like this in UITabBarController:
override func viewDidLoad() {
super.viewDidLoad()
//hide default tab bar
self.tabBar.isHidden = true
tabBarArea.frame.size.width = self.view.frame.width
tabBarArea.frame.origin.y = self.view.frame.height - tabBarArea.frame.height
self.view.addSubview(tabBarArea)
}
That works well. The tabBarArea is defined in the storyboard as a custom view for the UITabBarController. The custom view sits between the First Responder and the Exit icons in the top bar.
Now, the problem is that the UITabBarController will disappear as soon as we load a child view controller and this custom UIView area will vanish with it.
Is there a way to make this root custom view always present even when child view controllers are loaded in?
Thanks for input. I like the idea of this custom UIView area but this approach needs refinement. I also don't need it to be a traditional UITabBarController with tab bar items, etc. I'd like to break out of that mold and just have custom UIButtons are whatever in this view area.
In iOS 10, I could determine the list of navigation bar buttons I want to appear in viewDidLoad, and they would appear in the navigation bar as the view controller transitioned in.
In iOS 11, I can no longer do this. Whatever navigation bar buttons were set in interface builder are displayed as the view controller transitions in, and my custom list of buttons are not displayed until after the view finishes sliding in. Updating the buttons in viewWillAppear does not help.
Is this simply a bug in iOS 11, or is there something else I should be doing? Is there a workaround so I can continue to display buttons while the screen loads?
In the following example, I have set a button "Default Button" in the storyboard, and override it with an "Edit" button in viewDidLoad. The project is available on Github.
iOS 10
iOS 11
It looks like the issue is that navigation bar icons displayed during the transition appear to be fixed when the view controller is passed off to the navigation controller. By the time that viewDidLoad is called, the icons have already been fixed.
In order to fix this, we need to update the navigation bar icons on the view controller's navigationItem before the view controller is pushed onto the navigation controller stack.
One way to do this would be to setup the navigation bar icons in awakeFromNib. This is what #Joe's answer was effectively doing, because apparently viewDidLoad is called from awakeFromNib when isViewLoaded is true during awakeFromNib.
However, doing this in awakeFromNib prevents you from taking into account any properties set on the view controller in prepareForSegue. So another option (and the one that I am using) is to force the entire view to load in prepareForSegue by adding the line _ = controller.view after setting any desired properties.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showDetail" {
if let indexPath = tableView.indexPathForSelectedRow {
let controller = (segue.destination as! UINavigationController).topViewController as! DetailViewController
...
_ = controller.view
}
}
}
Move your Edit barButton code from viewDidLoad to isViewLoaded method as below.
override var isViewLoaded: Bool {
self.navigationItem.rightBarButtonItem = self.editButtonItem
return true
}
Output:
Note: Above code will fix the transition delay issue. Really, don't have much to explain why this happening. I experienced similar issue in iOS 10 as well NavigationBar delay updating barTintColor iOS10. It could be another bug in iOS11.
PS:
After reading Apple Doc about isViewLoaded and comparing other view loading methods. Its all about loading memory upon view loads.
You don't really need to move you barButton code at all.Just implement the isViewLoaded method and return to true as below:
override var isViewLoaded: Bool { return true}
In my storyboard, I have setup a navigation controller points to my MainVC, and it works just fine.
And now, I'm trying to add another view called "HelpVC", and I created one in the storyboard. It automatically shows the navigation bar on the top.
(MainVC segues to HelpVC)
However, I did everything else in code.
I had initWithView in the HelpVC which draws out the interface, BUT the navigation bar does not show up, so I can't go back to that previous view controller.
How do I make sure that the navigation bar shows up and works just like other view controllers? (segue back to the last view?)
It is not very clear from the post, but as I understood, you may want to try:
override func viewWillAppear(_ animated: Bool){
super.viewWillAppear(animated)
self.navigationController?.isNavigationBarHidden = false
}