swift - CollectionViewCell 发送上一张图像

Question

我正在发送从 collectionView 中选择的图像。问题是应用程序总是发送先前选择的图像。 indexPath 有什么问题？

这是 didSelectItemAt 函数:

override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let options = PHImageRequestOptions()
    options.deliveryMode = .highQualityFormat
    options.isNetworkAccessAllowed = true
    options.isSynchronous = true

    PHImageManager.default().requestImage(for: fetchResult.object(at: indexPath.item), targetSize: PHImageManagerMaximumSize, contentMode: .aspectFit, options: options, resultHandler: { image, error in   
        guard let image = image else { return }          
        self.image = image

    })

    performSegue(withIdentifier: "segue099", sender: self)

}

Answer 1

来自Docs

By default, this method executes asynchronously. If you call it from a background thread you may change the isSynchronous property of the options parameter to true to block the calling thread until either the requested image is ready or an error occurs, at which time Photos calls your result handler.

所以

performSegue(withIdentifier: "segue099", sender: self)

在获取图像之前运行，这会导致它传递旧图像，因此要么 true isSynchronous 或将 segue 放入回调内