在导航堆栈中保留容器视图的内容答案

【问题标题】：Keep contents of a container view in Navigation Stack在导航堆栈中保留容器视图的内容
【发布时间】：2023-03-25 03:13:01
【问题描述】：

我有一个HomeViewcontroller，我有一个分段控制器，可以在容器中的三个UICollectionViews 之间切换。

HomeViewContainer 是我的导航控制器的根

class HomeViewContainer: UIViewController {

    let displayOptionSegmentedControl: UISegmentedControl = {
        let segmentedControl = UISegmentedControl(items: ["Businesses","List","Map"])
        segmentedControl.setupBasicControllerColors()
        return segmentedControl
    }()

    let businessCollectionViewController = BusinessCollectionViewController(collectionViewLayout: UICollectionViewFlowLayout())
    let couponCollectionViewController = CouponCollectionViewController(collectionViewLayout: UICollectionViewFlowLayout())

    var currentSegmentIndex = 0

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.mainWhite()

        setupHeaderView()
        add(asChildViewController: businessCollectionViewController)

    }


    fileprivate func add(asChildViewController viewController: UIViewController) {
        contentContainer.addChildViewController(viewController)
        contentContainer.view.addSubview(viewController.view)
        viewController.view.frame = view.bounds
        viewController.didMove(toParentViewController: self)
    }

    fileprivate func remove(asChildViewController viewController: UIViewController) {

        viewController.willMove(toParentViewController: nil)
        viewController.view.removeFromSuperview()
        viewController.removeFromParentViewController()
    }

    @objc func segmentedValueChanged(_ sender: UISegmentedControl) {

        if currentSegmentIndex != sender.selectedSegmentIndex {
            switch currentSegmentIndex {
            case 0:
                remove(asChildViewController: businessCollectionViewController)
            case 1, 2:
                remove(asChildViewController: couponCollectionViewController)
            default:
                break
            }

            //Add new view based on user chosen option.
            switch sender.selectedSegmentIndex {
            case 0:
                currentSegmentIndex = sender.selectedSegmentIndex
                add(asChildViewController: businessCollectionViewController)
            case 1:
                currentSegmentIndex = sender.selectedSegmentIndex
                couponCollectionViewController.toggleMapHeaderOff()
                add(asChildViewController: couponCollectionViewController)
            case 2:
                currentSegmentIndex = sender.selectedSegmentIndex
                couponCollectionViewController.toggleMapheaderOn()
                add(asChildViewController: couponCollectionViewController)
            default:
                break
            }
        }
    }
}

视图显示正确，但是当我单击其中一个集合视图中的单元格时，问题就出现了。

例如，如果我单击 businessCollectionViewController 中的一个单元格，我尝试在我的导航控制器中显示另一个 ViewController，但我不能。

BusinessCollectionViewController

    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

        let bdvc = BusinessDetailViewController(collectionViewLayout: UICollectionViewFlowLayout())

        //NOTHING HAPPENS HERE
        self.navigationController?.present(bdvc, animated: false, completion: nil)
    }

如何使 ContentContainer 的内容仍在 HomeViewContainer 导航堆栈中？我怀疑它与我的 HomeViewContainer 类中的 add() 方法有关，但我不知道采取什么合适的解决方案。

【问题讨论】：

标签： swift uicollectionview uinavigationcontroller

【解决方案1】：

找到了解决办法。我需要将 ContentContainer 作为孩子实际添加到我的 HomeViewContainer 中。

在 HomeViewContainer 中

override func viewDidLoad() {
    super.viewDidLoad()
    view.backgroundColor = UIColor.mainWhite()

    //Added this line!
    addChildVC(vc: contentContainer, toView: self.view)

    setupHeaderView()
    add(asChildViewController: businessCollectionViewController)

}

//And added this helper method
public func addChildVC(vc: UIViewController, toView containerView: UIView) {
    addChildViewController(vc)
    let frame = CGRect(x: 0, y: 0, width: containerView.frame.width, height: containerView.frame.height)
    print("Container Frame = \(containerView.frame)")
    vc.view.frame = frame
    containerView.addSubview(vc.view)
    vc.didMove(toParentViewController: self)
}

【讨论】：