Question

我正在尝试将此字符串从一个UICollectionViewCell传递到UICollectionViewController。我希望＆＃34;让我们开始吧！＆＃34;继续我的导航标题...下面是我的代码，我无法弄清楚为什么字符串没有通过。

// UICOLLECTIONVIEWCELL --> This is the first UICollectionViewCell
    @objc func getStartedAction() {
        let confirmingTapActionButton1 = "Let's Get Started!"
        let signUpFlowController1 = SignUpFlowController()
        signUpFlowController1.welcomeCellPassedStringForAction1 = confirmingTapActionButton1
    }


// UICollectionViewController --> This is the second UICollectionViewController
    class SignUpFlowController: UICollectionViewController, UICollectionViewDelegateFlowLayout {

        var welcomeCellPassedStringForAction1: String? = nil

        override func viewDidLoad() {
            super.viewDidLoad()
            collectionView?.backgroundColor = .white

            // NAV BAR STUFF BELOW
            self.title = welcomeCellPassedStringForAction1

        }

Answer 1

您可以使用协议

执行此操作

制定协议：

protocol NavTitleProtocol{
func setNavTitle(title: String)
}

使您的CollectionViewController符合协议并覆盖setNavTitle方法：

extension YourCollectionViewController: NavTitleProtocol{
func setNavTitle(title: String) {
    self.title = title
}
}

在您的单元格中，拥有NavTitleProtocol类型的委托属性：

class YourCollectionViewCell: UICollectionViewCell{
var delegate: NavTitleProtocol?

@objc func getStartedAction() {
    let confirmingTapActionButton1 = "Let's Get Started!"
//   let signUpFlowController1 = SignUpFlowController()
//        signUpFlowController1.welcomeCellPassedStringForAction1 = confirmingTapActionButton1
    delegate?.setNavTitle(title: confirmingTapActionButton1)
}
}

在创建collectionView单元格时将collectionViewController指定为委托：

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "YourIdentifier", for: indexPath) as! YourCollectionViewCell
    cell.delegate = self
}

当您在单元格中执行选择器时，将访问delegate属性，并且将调用您在CollectionViewController中重写的方法。

Answer 2

首先是这一行

let signUpFlowController1 = SignUpFlowController()

创建一个除了显示的实例之外的新实例，因此您必须使用该委托来捕获所呈现的实例

func collectionView(_ collectionView: UICollectionView,
                    cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    cell.myInstance = self
}

class customCell:UICollectionViewCell {
    var myInstance:SignUpFlowController!

    @objc func getStartedAction() {
        let confirmingTapActionButton1 = "Let's Get Started!"
        myInstance.welcomeCellPassedStringForAction1 = confirmingTapActionButton1
    }
}

Swift 4：将UICollectionViewCell中的字符串传递给UICollectionViewController

2 个答案: