在 Swift 4 中将数据从 CollectionView 传递到 DetailVC [英] Passing data from CollectionView to DetailVC in Swift 4

问题描述

我的 CollectionView 应该将一个类模型传递给 DetailViewController，但是当我点击一个单元格时，我得到了 nil 错误.

<块引用>

致命错误:在隐式解包时意外发现 nil可选值

CollectionViewController 以编程方式嵌入在 TabBarController 上.

集合视图

<预><代码>func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection 部分: Int) ->整数{返回 soundArray.count}func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) ->UICollectionViewCell {if let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "SoundCell", for: indexPath) as?声音单元{让 SoundClass = soundArray[indexPath.row]cell.updateUI(SoundClass: SoundClass)返回单元格} 别的 {返回 UICollectionViewCell()}}func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {self.performSegue(withIdentifier: "seguetosound", sender: self)}覆盖 func prepare(for segue: UIStoryboardSegue, sender: Any?) {如果 segue.identifier == "seguetosound" {如果让 detailVC = segue.destination 作为?详情SecondVC让声音 = 发件人为?声音类{detailVC.SoundClass = 声音}}

细节视图控制器

class DetailSecondVC: UIViewController, UIWebViewDelegate {私有变量_SoundClass:SoundClass！var SoundClass: SoundClass {得到 {返回_SoundClass} 放 {_SoundClass = newValue}}

你知道我在这里遗漏了什么吗?我用一个简单的白屏测试了 segue，它可以工作，但是当我尝试传递数据时，它失败了.

解决方案

我认为解决方案是从视图控制器而不是从单元格进行转场，但正如马特所说，转场从单元格中是正确的但我只需要删除 didSelectItemAt

的实现

My CollectionView should pass a class model to DetailViewController, but when I tap on a cell I get the nil error.

Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value

The CollectionViewController is embedded programmatically on a TabBarController.

Collection View

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return soundArray.count
    }

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

    if let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "SoundCell", for: indexPath) as? SoundCell {
    let SoundClass = soundArray[indexPath.row]
    cell.updateUI(SoundClass: SoundClass)
    return cell

    } else {
    return UICollectionViewCell()
    }
}

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

    self.performSegue(withIdentifier: "seguetosound", sender: self)

  }

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

    if segue.identifier == "seguetosound" {
    if let detailVC = segue.destination as? DetailSecondVC
    let sound = sender as? SoundClass { 
    detailVC.SoundClass = sound 

    }
 }

Detail View Controller

class DetailSecondVC: UIViewController, UIWebViewDelegate {

private var _SoundClass: SoundClass!

var SoundClass: SoundClass {
        get {
            return _SoundClass
        } set {
            _SoundClass = newValue
        }
    }

Do you know what I am missing here? I tested the segue with a simple white screen and it works but when I try to pass the data, it fails.

解决方案

Edited: I thought the solution was to make the segue from the view controller instead of from the cell, but as matt said, the segue was correct from the cell but I just had to remove the implementation of didSelectItemAt

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