I'm trying to send some data with a delegate call from a Parent PageViewController to a Child ViewController. However, at the moment, this doesn't work. I have my views set up like this:
- ViewController (which contains a map view, in which data needs to be passed to the ParentPageVC)
- ParentPageViewController (which then needs to pass the data received to ChildTwoVC)
- ChildOneViewController
- ChildTwoViewController (displays the data received from parent)
Interestingly, I can send data between the children inside the parent PageViewController. I can also send data from the initial ViewController to the ParentPageViewController just fine. I just cannot send the data from the Parent TO the Child.
Here's my Parent PageViewController:
protocol ParentPageViewDelegate: class {
func viewNeedsDismiss()
}
class ParentPageViewController: UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource, ParentPageViewDelegate, MyMapDataViewDelegate {
lazy var childViewControllers = [UIViewController]()
weak var childTwoViewDelegate: ChildTwoViewDelegate?
override func viewDidLoad() {
super.viewDidLoad()
self.dataSource = self
self.delegate = self
let childOneViewController = storyboard?.instantiateViewController(withIdentifier: "ChildOneViewController") as! ChildOneViewController
let childTwoViewController = storyboard?.instantiateViewController(withIdentifier: "ChildTwoViewController") as! ChildTwoViewController
childOneViewController.childOneDelegate = childTwoViewController
childTwoViewController.parentPageViewDelegate = self
self.childTwoViewDelegate = childTwoViewController
workoutViewControllers.append(childOneViewController)
workoutViewControllers.append(childTwoViewController)
if let firstViewController = workoutViewControllers.last {
setViewControllers([firstViewController], direction: .forward, animated: true, completion: nil)
}
let pageControl = UIPageControl.appearance(whenContainedInInstancesOf: [StartWorkoutPageViewController.self])
pageControl.currentPageIndicatorTintColor = .orange
pageControl.pageIndicatorTintColor = .gray
}
// MARK: Delegates
// ParentPageView Delegate
func viewNeedsDismiss() {
// Works fine
print("WillDismiss")
}
// MyMapDataView Delegate
func updateStats(distance: String, rawDistance: Double, speedPace: String) {
print("Method Was Called") // Yes, the method is called.
// However nothing happens in the below line... it doesn't call 'childTwoViewDelegate'
childTwoViewDelegate?.updateStats(distance: distance, rawDistance: rawDistance, speedPace: speedPace)
}
// MARK: PageView DataSource
func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = childViewControllers.firstIndex(of: viewController) else {
return nil
}
let previousIndex = viewControllerIndex - 1
guard previousIndex >= 0 else {
return childViewControllers.last
}
guard childViewControllers.count > previousIndex else {
return nil
}
return childViewControllers[previousIndex]
}
func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = childViewControllers.firstIndex(of: viewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1
let childViewControllersCount = childViewControllers.count
guard childViewControllersCount != nextIndex else {
return workoutViewControllers.first
}
guard childViewControllersCount > nextIndex else {
return nil
}
return childViewControllers[nextIndex]
}
func presentationCount(for pageViewController: UIPageViewController) -> Int {
return childViewControllers.count
}
func presentationIndex(for pageViewController: UIPageViewController) -> Int {
guard let firstViewController = viewControllers?.first, let firstViewControllerIndex = workoutViewControllers.firstIndex(of: firstViewController) else {
return 0
}
return firstViewControllerIndex
}
}
My Child ViewController:
protocol ChildTwoViewDelegate: class {
func updateStats(distance: String, rawDistance: Double, speedPace: String)
}
class ChildTwoViewController: UIViewController, ChildTwoViewDelegate {
weak var parentPageViewDelegate: ParentPageViewDelegate?
@IBAction func closeButton(_sender: Any) {
// Works fine
parentPageViewDelegate?.viewNeedsDismiss()
}
override func viewDidLoad() {
super.viewDidLoad()
}
// MARK: Delegates
// ChildTwoViewDelegate
func updateStats(distance: String, rawDistance: Double, speedPace: String) {
// This method does not get called.
print("Method Was Called in Child")
}
}
Thank you!
question from:
https://stackoverflow.com/questions/65946997/child-viewcontroller-not-receiving-delegate-calls-from-parent-pageviewcontroller 与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
