Im having trouble setting a nssplitviewcontroller's split view's view controller. I have a reference from the story board and am trying to set the items view controller programmatically:
override func viewDidLoad() {
dash = storyBoard.instantiateControllerWithIdentifier("dash_viewcontroller") as? NSViewController
print(dash)
main_view.viewController = dash!
}
I get this error from the console(doesn't crash) and doesn't show the programmatically set vc:
2016-02-21 10:03:19.475 HealthDash[62950:3960447] Failed to set (contentViewController) user defined inspected property on (NSWindow): Cannot remove a SplitViewItem's viewController if it is currently in a SplitViewController
Looks like the splitViewItem has a content controller that is actively being displayed. My guess: first you will have to remove that view controller from screen before you can replace it. Probably easier to create a new NSSplitItemView, add that to the NSSplitViewController and remove unwanted NSSplitItemView (and their associated view controllers).
Related
I'm building an app with three views and I want the user to be able to swipe between them but also navigate between them by using custom buttons, like browsing in safari but only with three available views. The user can navigate between them in a somewhat random order and I provide back and forward buttons in a toolbar.
After reading Apple's documentation I believe history mode is the option I'm looking for as I can provide the views separately and navigation is not predefined like in book mode, however when I implement it it adds my view to the arrangedObjects property but the view itself doesn't change. I've correctly wired the page controller view programmatically to a subview of the app's contentView and I can see said view correctly displayed while debugging the view hierarchy.
The "Page Controller Managed View" is set as NSPageController.view programatically.
When I try using navigateForward(to:) the view gets added correctly to the arrangedObjects and the selectedIndex is correctly set but the NSPageController.view doesn't change at all (remains a blank NSView like the loaded view from storyboard). This is my code:
class MainViewController: NSViewController {
// MARK - Instance Properties
var notificationObservers: Array<NSObjectProtocol> = []
var pageController: NSPageController?
// MARK - Interface Builder Outlets
#IBOutlet var mainContentView: NSView? // Named "Page Controller Managed View" in storyboard
override func viewDidLoad() {
super.viewDidLoad()
pageController = (NSStoryboard.main!.instantiateController(
withIdentifier: "MainPageController") as! NSPageController)
pageController!.delegate = AppDelegate
pageController!.view = mainContentView!
notificationObservers.append(
NotificationCenter.default.addObserver(
forName: NSApplication.didFinishLaunchingNotification,
object: NSApp,
queue: .main,
using: { [weak self] (notification) in
// If the 'arrangedObjects' property is 0 it means no other object has set the first view
if self?.pageController!.arrangedObjects.count == 0 {
// Set the first view
self.pageController!.navigateForward(to: AppDelegate.firstView.nsView)
}
})
)
}
deinit {
// Perform cleanup of any Apple Notification Center notifications to which we may have registered
notificationObservers.forEach { (observer) in
NotificationCenter.default.removeObserver(observer)
}
}
}
This is the view hierarchy while running the app:
What am I doing wrong? Why is the page controller view not being updated with the navigateForward(to:) view?
This could shorten the amount of code I have to use by a lot compared to using view controllers (Book mode) so any help is appreciated.
I have a tab bar app where one of the views is a UITableViewController containing static cells as content with 1 section and 1 row.
I want the Large Title to be set to "Always," so I made the selection on the storyboard and the title was large on the simulator. Now when the user taps "Start Chat," the app will segue to the Virtual Assistant View Controller, where the Large Title is set to "Never" on the storyboard. Now the problem is that when the user segues back to the previous view controller with the "Start Chat" table view cell, the title is not large anymore.
It is interesting that when I set the table view to be scrollable, the title becomes large again upon dragging down the table view. I made sure the navigation bar on the Navigation Controller storyboard is checked with the "Prefers Large Titles." I am using Xcode 11, and this was not a problem when using Xcode 10.
I tried creating a custom class for the view with the start chat button and this code did not work in making the title large from a segue back:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
navigationController?.navigationItem.largeTitleDisplayMode = .always
navigationController?.navigationBar.prefersLargeTitles = true
What else could I do? Any help will be greatly appreciated!
I'd use willMove(toParent:) to change the title back before the segue is performed.
override func willMove(toParent parent: UIViewController?) {
navigationController?.navigationItem.largeTitleDisplayMode = .always
navigationController?.navigationBar.prefersLargeTitles = true
}
Set the properties when setting up the UINavigationController, before presenting it. If you already presented the navigation controller, try doing this to force-update the navigation bar:
navigationController?.navigationItem.prompt = ""
navigationController?.navigationItem.prompt = nil
I took this workaround from this question.
In your particular case, it would be better to subclass the navigation controller and set those properties in its viewDidLoad method, so its properties (largeTitleDisplayMode and prefersLargeTitles) are set in a self-contained code.
I have : navigation controller -> tableViewController -> tab bar Controller -> ViewController1 / ViewController2 / ViewController3
I click on a cell on the TableViewController and I open the TabBar. All is OK
But, I wanted to have more details from the datas in the TableViewController so I decided to make a popup with the content of the cell. I found this tutorial https://www.youtube.com/watch?v=S5i8n_bqblE => GREAT ! It's about the use of segue "present modally" with a viewcontroller containing the popup. I made a link from the popup to the tabBarController and I lose the Navigation Bar
I tried to play with navigationBar but nothing is working. I changed the type of segue but I don't obtain what I want.
I think the problem come from the type of segue. It's OK if I use it like a go/back in viewController. Do you have any solution about using this sort of popup or do I have to use another way ?
Thanks
Ok, let's take a look.
Navigation Bar is a view which is provided by Navigation Controller. Sometimes we are confused with navigation bars and navigation items. Navigation bar is the only one and it belongs to navigation controller, navigation item belongs to individual view controller from navigation stack. So, first step is simple: if you want navigation bar, wrap your modally presented controller into navigation stack.
Yes, you will face other problem, the blurred view of previous controller will become a black area. Why? there is special object called Presentation Controller (UIPresentationController) which is responsible for how controller will be presented. And it hides view of previous controller by default (in sake of performance, I think).
Ok, let's move. We can create custom presentation controller and tell it not to hide view of previous controller. Like this:
class CustomPresentationController: UIPresentationController {
override var shouldRemovePresentersView: Bool {
return false
}
}
Next step. In controller we want present modally we have to specify to things: we want to use custom presentation controller and we also want to adjust delegate object for transitioning (where we can specify custom presentation controller). The trick is that you have to do it inside initialiser, because viewDidLoad is too late: controller had been already initialised:
class PopupViewController: UIViewController {
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
modalPresentationStyle = .custom
transitioningDelegate = self
}
}
Final step. When PopupViewController became delegate for its own transitioning, it means this controller is responsible for all of them. In our particular case popup controller provides custom version of presentation controller. Like this:
extension PopupViewController: UIViewControllerTransitioningDelegate {
func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController? {
return CustomPresentationController(presentedViewController: presented, presenting: presenting)
}
}
That's all. Now you should see view of previous controller.
I am making an app at the moment where 1 screen has a segmented control with 3 segments. Initially I had 1 table view and when you change segment I would simply change the data source/cell etc and reload the table. While this works great there is always the problem that when you change segments it will not remember your last scroll position because the table view gets reloaded.
I tried to get around this with storing offset position, rows etc but I could never get it to work like I wanted. Seems especially annoying when you have different cell types for the segments and they are self sizing as well.
I than decided to have a master view controller with the segmented control and 3 container views with their own VC and table view for each segment. I simply hide/show the correct container view when changing segments. This also works great but I have 1 problem with iOS 11 style large headers. Only the 1st container view added as a subview to the ViewControllers view manipulates the collasping/expanding of the title when you scroll.
Therefore when I change to the 2nd or 3rd container view and start scrolling I do not get the large title collapsing animation. How can I get around that?
I tried the following
1) Change Container view zPosition when changing segments
2) Move the container view to the front by calling view.bringSubview(toFront: ...)
3) Looping through the subviews and calling
view.exchangeSubview(at: 0, withSubviewAt: ...)
I believe I could remove all container views and add the one I need again and give them constraints but I wonder if there is a more straight forward solution.
Or if someone has a good solution to remember a tableViews scroll position before reloading it I would appreciate that too.
So I found an answer that seems to work for me, thanks to this great article. https://cocoacasts.com/managing-view-controllers-with-container-view-controllers/
Essentially what I did is
1) Remove the ContainerViews and Segues from the MasterViewController Storyboard.
2) Add a lazy property for each VC of the segmented control in the MasterViewController. They are lazy so that they only get initialised when you actually need them
lazy var viewController1: LibraryViewController = {
let viewController = UIStoryboard.libraryViewController // convenience property to create the VC from Storyboard
// do other set up if required.
return viewController
}()
lazy var viewController2: LibraryViewController = {
let viewController = UIStoryboard.libraryViewController // convenience property to create the VC from Storyboard
// do other set up if required.
return viewController
}()
3) Create an extension of UIViewController with the following 2 methods. I added them in an extension purely for code organisation as they might be reused on other ViewControllers.
extension UIViewController {
func add(asChildViewController viewController: UIViewController) {
// Add Child View Controller
addChildViewController(viewController)
// Add Child View as Subview
view.addSubview(viewController.view)
// Configure Child View
viewController.view.frame = view.bounds
viewController.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
// Notify Child View Controller
viewController.didMove(toParentViewController: self)
}
func remove(asChildViewController viewController: UIViewController) {
// Notify Child View Controller
viewController.willMove(toParentViewController: nil)
// Remove Child View From Superview
viewController.view.removeFromSuperview()
// Notify Child View Controller
viewController.removeFromParentViewController()
}
}
4) Now in my segmented control method that gets called when you change segment I simply add the correct ViewController. The nice thing is that remove/adding them does not actually deallocate them.
func didPressSegmentedControl() {
if segmentedControl.selectedSegmentIndex == 0 {
remove(asChildViewController: viewController2)
add(asChildViewController: viewController1)
} else {
remove(asChildViewController: viewController1)
add(asChildViewController: viewController2)
}
}
5) Make sure you call the method at point 4 in ViewDidLoad so that the correct VC is added when the VC is loaded the 1st time.
func viewDidLoad() {
super.viewDidLoad()
didPressSegmentedControl()
}
This way when we remove a ChildViewController and add another one it will always be the the top VC in the subviews array and I get my nice title collapsing animation.
Another added benefit of this approach is that if you never go to a particular segment that particular VC will never get initialised, because they are lazy properties, which should help with efficiency.
Hope this helps somebody trying to do the same.
This is a horrible issue which I hope will be resolved soon, but there is another fix - although I freely admit that this is a nasty hack.
Basically, the issue only applies to the FIRST container view in the hierarchy. Add another container view to your hierarchy. Set it as hidden, then delete its segue and its target view controller just to be neat. Finally, make sure that this is the first container view in the hierarchy by dragging it to the top of the list.
I have a label in a second viewController in Swift, and I want change this between my firstViewController. I try this with prepareForSegue: also with ChildView and ParentView and accessing to label since parentView.. But I get error..
What is the correct form to can make this?
Try declared secondVIew:
class ViewController: UIViewController {
var v = View2Controller()
#IBAction func but(sender : AnyObject) {
v.label2.text = "newText" //Here get the error EXC_BAD_INSTRUCTION
}
...
class View2Controller: UIViewController {
#IBOutlet var label2 : UILabel
Thanks!
The more code you provide the easier it is to get answers.
In your case, you are initializing a band new View2Controller. Since label2 is an IBOutlet it expects data from a nib file. Since it didn't get any of this data, label2 is going to be nil hence why you get a EXC_BAD_INSTRUCTION crash.
You can access the root view controller of a navigation controller because navigation controllers are special in that they have their own stack and maintain their own view hierarchy. This is why you have to push and pop view controllers in a navigation controller. This also allows child controllers to maintain a reference to its parent controller.
The proper solution for your situation would be to use protocols. Otherwise give View2Controller a property and reference to ViewController then make changes to ViewController through that property.