swift - 无法使用全局变量访问 collectionView 单元格变量

Question

在这里，我创建了一个 collectionView 单元格变量来访问这两个对象。但是无法访问单元格变量里面的对象

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    var cell: UICollectionViewCell!
    if collectionView == collectionView1 {
        cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellAttachment", for: indexPath) as! AttachmentCell
        cell.imgAttachment.image = imageArray1[indexPath.row]
        cell.delegate = self
    }
    else if collectionView == collectionView2 {
       cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellAttachmentView", for: indexPath) as! AttachmentViewCell
       cell.imgFileIcon.image = imgArray2[indexPath.row].fileIcon
    }
    return cell

Value of type 'UICollectionViewCell?' has no member 'imgAttachment'

Answer 1

问题就出在这里

var cell: UICollectionViewCell!

您已将单元格声明为 UICollectionViewCell 类型。因此，无论您在其中存储哪个子类，您的单元格都只会是 UICollectionViewCell 类型。

你应该这样改，

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    if collectionView === collectionView1 {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellAttachment", for: indexPath) as! AttachmentCell
        cell.imgAttachment.image = imageArray1[indexPath.row]
        cell.delegate = self
        return cell
    } else if collectionView === collectionView2 {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellAttachmentView", for: indexPath) as! AttachmentViewCell
        cell.imgFileIcon.image = imgArray2[indexPath.row].fileIcon
        return cell
    } else {
        // Return the proper cell for other cases
    }
}

或者，如果您坚持在委托(delegate)的末尾只需要一个返回语句，那么您可以这样做，

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    var yourCell: UICollectionViewCell!
    if collectionView === collectionView1 {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellAttachment", for: indexPath) as! AttachmentCell
        cell.imgAttachment.image = imageArray1[indexPath.row]
        cell.delegate = self
        yourCell = cell
    } else if collectionView === collectionView2 {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellAttachmentView", for: indexPath) as! AttachmentViewCell
        cell.imgFileIcon.image = imgArray2[indexPath.row].fileIcon
        yourCell = cell
    } else {
        // Return the proper cell for other cases
    }
    return yourCell
}