以编程方式从CollectionView单元推送viewController不起作用 - swift

Question

我是一个新的iOS编程。 现在我通过不使用storyboard创建一个示例应用程序，我为主类实现了UICollectionView ，滚动方向是垂直的。 一个特定的单元格我为水平方向添加了另一个UICollectionView 。 问题是水平滚动方向的cell没有推到另一个点击它的视图控制器上。

这是我在AppDelegate设置的rootViewController

window = UIWindow(frame: UIScreen.main.bounds)
window?.makeKeyAndVisible()
let navigation = UINavigationController(rootViewController: CategoryController())
window?.rootViewController = navigation

这是我实现tableView CategoryController

tableView.register(TableCell.self, forCellReuseIdentifier: cellId)

override func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 5
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: cellId, for: indexPath)

    return cell
}

override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 120
}

对于tableView ，当我想要导航到特定控制器时，我点击特定单元格工作正常

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    print(indexPath.item)
    let view = DetailEachCellController()
    navigationController?.pushViewController(view, animated: true)
}

问题是在DetailEachCellController我使用UICollectionView列出一些数据，当我点击特定单元格时没有导航到新控制器

这里DetailEachCellController为UIViewController

var collectionDetailView: UICollectionView!
collectionDetailView.register(DetailContactCell.self, forCellWithReuseIdentifier: cellIdContact)
collectionDetailView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: cellIdContent)

func setupCollectionView() {
    collectionDetailView.topAnchor.constraint(equalTo: detailContent.topAnchor).isActive = true
    collectionDetailView.widthAnchor.constraint(equalTo: detailContent.widthAnchor).isActive = true
    collectionDetailView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
    collectionDetailView.backgroundColor = .white 
}

func callAction() {
    print("pushing view")
    let view = UIViewController()
    self.navigationController?.pushViewController(view, animated: true)
}

这里是UICollectionViewFlowLayout的委托

extension DetailEachCellController : UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 2
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        if indexPath.item == 0 {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdContact, for: indexPath)

            return cell
        }
        else {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdContent, for: indexPath)
            cell.backgroundColor = .blue
            return cell
        }
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        if indexPath.item == 1 {
          return CGSize(width: view.frame.width, height: 250)
        }
        return CGSize(width: view.frame.width, height: 120)
    }
}

这里是DetailContactCell ，我为用户点击添加了一些按钮，并为下一个视图添加了更多按钮，但它没有移动但是调用了该函数。

class DetailContactCell: UICollectionViewCell {

var eachCellController: DetailEachCellController?

lazy var callButton: UIButton = {

    let button = UIButton()
    button.translatesAutoresizingMaskIntoConstraints = false
    button.layer.shadowOpacity = 0.25
    button.backgroundColor = .white
    button.setTitle("CALL", for: .normal)
    button.layer.cornerRadius = 10
    button.layer.shadowOffset = CGSize(width: 0, height: 10)
    button.layer.shadowRadius = 10
    return button
}()
lazy var bookButton: UIButton = {

    let button = UIButton()
    button.translatesAutoresizingMaskIntoConstraints = false
    button.layer.shadowOpacity = 0.25
    button.backgroundColor = .white
    button.layer.cornerRadius = 10
    button.layer.shadowOffset = CGSize(width: 0, height: 10)
    button.layer.shadowRadius = 10
    return button
}()
override init(frame: CGRect) {
    super.init(frame: frame)
    addSubview(callButton)
    addSubview(bookButton)
    callButton.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
    callButton.leftAnchor.constraint(equalTo: self.leftAnchor, constant: 15).isActive = true
    callButton.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 1/2.5).isActive = true
    callButton.heightAnchor.constraint(equalToConstant: 60).isActive = true

    bookButton.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
    bookButton.rightAnchor.constraint(equalTo: self.rightAnchor, constant: -15).isActive = true
    bookButton.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 1/2.5).isActive = true
    bookButton.heightAnchor.constraint(equalToConstant: 60).isActive = true

    self.actionButton()
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

func actionButton() {
    callButton.addTarget(self, action: #selector(callBtn), for: .touchUpInside)
}

@objc func callBtn() {
    print("calling")
    eachCellController = DetailEachCellController()
    eachCellController?.callAction()
}

}

Answer 1

因为这

// eachCellController = DetailEachCellController（）//注释它

是另一个不是现有的VC

eachCellController?.callAction()

你需要在cellForItemAt发送自己

cell.eachCellController = self

//

@objc func callBtn() {
   print("calling")
   eachCellController?.callAction()
}

Answer 2

您无法从UICollectionViewCell类内部将新视图控制器推送到导航控制器堆栈。

这样做的方法是告诉DetailEachCellController （通过委托方法或回调处理程序）按钮被单击，然后只有从 DetailEachCellController你可以推动视图控制器。

这是一个类似的线程

Answer 3

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    if indexPath.item == 0 {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdContact, for: indexPath) as! DetailContactCell
        // Here is line add to `UICollectionViewFlowLayout`
        cell.eachCellController = self

        return cell
    }else {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdContent, for: indexPath)
        cell.backgroundColor = .blue
        return cell
    }

}

Answer 4

将UIViewController的强对象传递给单元格并不方便。 您可以创建保留周期，您的视图控制器将永远不会被释放，因此它可能会在将来导致内存问题

要解决此问题，您可以选择以下选项

1. 使用委托
2. 使用闭包
3. 使用addTarget在viewcontroller本身中实现Button动作

由于闭包选项很简单，我给你一个实现它的例子。

在集合视图单元格中添加以下属性

var callBtnTapped : (() -> ())?

现在进来

@objc func callBtn() {
    print("calling") 
     // Check that target has implemented closure ? 
     if let clouser = self.callBtnTapped {
            clouser(screenShotID)
      }
}

在视图中，控制器cellForItem将body添加到闭包中

     cell.callBtnTapped = {[weak self]  in
        guard let strongSelf = self   else  {return}
        strongSelf. callAction()
        // It will be called when button tapped 
    }

希望它有所帮助