Haneke无法使用Swift与AWS SDK配合使用

Question

我正在尝试与AWS SDK集成，但图像不显示。

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("MyCollectionViewCell", forIndexPath: indexPath) as! MyCollectionViewCell

        let downloadURL = NSURL(fileURLWithPath: NSTemporaryDirectory()).URLByAppendingPathComponent("myImage.jpg")
        let downloadRequest = AWSS3TransferManagerDownloadRequest()
        downloadRequest.bucket = "stg"
        downloadRequest.key = "myImage.jpg"
        downloadRequest.downloadingFileURL = downloadURL

        let transferManager = AWSS3TransferManager.defaultS3TransferManager()
        transferManager.download(downloadRequest).continueWithBlock { (task) -> AnyObject! in
            if task.error != nil {
                print("Failed to download S3 with error \(task.error)")
            }

            if task.result != nil {
                //let output = task.result as! AWSS3TransferManagerDownloadOutput
                cell.imageView.contentMode = UIViewContentMode.ScaleAspectFit
                cell.imageView?.hnk_setImageFromURL(downloadURL)
            }
            return nil
        }
        return cell
    }

Answer 1

问题是您正在后台线程中更新UI。您应该用.continueWithExecutor(AWSExecutor.mainThreadExecutor(), withBlock: { (task) -> AnyObject! in替换.continueWithBlock { (task) -> AnyObject! in，以便在主线程中运行该块。

此外，如果您正在编写新的应用程序，我建议使用AWSS3TransferUtility而不是AWSS3TransferManager，因为我们将把开发重点放在传输实用程序上，并将逐步淘汰对传输管理器的支持。