[英]Use of unresolved identifier 'cell' in xcode project
在我的匹配應用程序Xcode項目中,我有一個錯誤說明:
使用未解析的標識符“cell”。
我的代碼:
import UIKit
class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
}
@IBOutlet weak var collectionView: UICollectionView!
var model = CardModel()
var cardArray:[Card] = []
override func viewDidLoad() {
super.viewDidLoad()
//call the getCards method of the card model
cardArray = model.getCards()
collectionView.delegate = self
collectionView.dataSource = self
}
//mark: -UICollectionView Protocol Methods
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return cardArray.count
}
func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
//get a cardCollectionViewcell object
let cell =
collectionView.dequeueReusableCell(withReuseIdentifier: "CardCell", for: indexPath) as! CardCollectionViewCell
//get card that
let card = cardArray[indexPath.row]
cell.setCard(card)
return
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
_ = collectionView.cellForItem(at: indexPath) as!CardCollectionViewCell
//flip the card
cell.flip() <--------- THIS IS THE ERROR
一旦錯誤得到修復,我應該可以在假iPhone上運行匹配應用程序示例。 它可以讓我在點擊時翻轉卡片。
首先,你是在濫用collectionView:willDisplay:forItemAt
。 將所有內容移動到collectionView:cellForItemAt
,將return
替換為return cell
並刪除willDisplay:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CardCell", for: indexPath) as! CardCollectionViewCell
//get card that
let card = cardArray[indexPath.row]
cell.setCard(card)
return cell
}
func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) { ... }
錯誤非常明確:您從未聲明cell
是didSelectItemAt
的范圍。 更改
let cell = collectionView.cellForItem(at: indexPath) as! CardCollectionViewCell
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