Question

我正在尝试从collectionViewController中选择另一个ViewController，并且还尝试获取索引并适当地传递数据，但是当我选择一个单元格时，detailVC仅显示但没有打印出任何东西或任何东西

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

        if segue.identifier == DETAIL_VC {

            print("ITEM SELECTED ")
            let vc = segue.destination as! DetailVC
            guard let selectedIndexPath = sender as? IndexPath else { return }
            let flickerPhoto = ServiceProvider.instance.flickerPhotos[selectedIndexPath.item]

            print("ITEM SELECTED ")
            vc.titleLabel.text = flickerPhoto.title
        }
}

什么都不会打印

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


        let flickerPhoto = ServiceProvider.instance.flickerPhotos[indexPath.item]
        let destinationVC = storyboard?.instantiateViewController(withIdentifier: DETAIL_VC) as! DetailVC
        destinationVC.titleLabel.text = flickerPhoto.title

    }

我收到错误Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value

Answer 1

您需要将源vc的黄色图标（而非单元格）中名为DETAIL_VC的segue连接到目标，并在didSelectItemAt内使用它

self.performSegue(withIdentifier:DETAIL_VC,sender:indexPath)

当您访问在加载vc之前为零的插座时崩溃，您可以尝试将数据作为字符串发送并将其设置在目标vc的viewDidLoad中

destinationVC.titleValue = flickerPhoto.title

class DetailVC:UIViewController {

    var titleValue:String = ""

   // set it to the label text in `viewDidLoad`

    override func viewDidLoad() {

      super.viewDidLoad()

        self.titleLabel.text = titleValue
     }
}

准备从collectionviewcell进行segue，而不替换已索引的项目

1 个答案: