我有一个奇怪的问题，我正在尝试构建一个 Action 扩展，它将从提供的图像中扫描条形码。这是代码。

override func viewDidLoad() {
    super.viewDidLoad()

    // Get the item[s] we're handling from the extension context.

    // For example, look for an image and place it into an image view.
    // Replace this with something appropriate for the type[s] your extension supports.
    var imageFound = false
    for item: AnyObject in self.extensionContext!.inputItems {
        let inputItem = item as NSExtensionItem
        for provider: AnyObject in inputItem.attachments! {
            let itemProvider = provider as NSItemProvider
            if itemProvider.hasItemConformingToTypeIdentifier(kUTTypeImage as NSString) {
                // This is an image. We'll load it, then place it in our image view.
                weak var weakImageView = self.imageView
                itemProvider.loadItemForTypeIdentifier(kUTTypeImage as NSString, options: nil, completionHandler: { (image, error) in
                    if image != nil {
                        dispatch_async(dispatch_get_main_queue(),{
                            if let imageView = weakImageView {
                                var imageToSet: UIImage? = image as? UIImage
                                imageView.image = image as? UIImage
                            }

                            self.imageToScan = self.imageView.image
                            self.scanFromImage(self.imageToScan!)
                        })
                    }
                })

                imageFound = true
                break
            }
        }

        if (imageFound) {
            // We only handle one image, so stop looking for more.
            break
        }
    }
}

现在，每当我尝试获取 UIImage 时，我总是得到 nil，而在图像中我可以看到接收到图像。但是当我尝试从该图像中获取 UIImage 时，它​​总是返回 nil。这是可能有帮助的调试屏幕截图

更新:这是接收到的图像的描述:

Printing description of image: (NSSecureCoding!) image = (instance_type = Builtin.RawPointer = 0x15d674c0 -> 0x32b6be5c (void *)0x32b6be70: NSURL)

我已经使用 Objective-C 创建了相同的扩展并且它可以工作，但不是很快。这是 Objective-C 代码:

- (void)viewDidLoad {
[super viewDidLoad];

// Get the item[s] we're handling from the extension context.

// For example, look for an image and place it into an image view.
// Replace this with something appropriate for the type[s] your extension supports.
BOOL imageFound = NO;
for (NSExtensionItem *item in self.extensionContext.inputItems) {
    for (NSItemProvider *itemProvider in item.attachments) {
        if ([itemProvider hasItemConformingToTypeIdentifier:(NSString *)kUTTypeImage]) {
            // This is an image. We'll load it, then place it in our image view.
            __weak UIImageView *imageView = self.imageView;
            [itemProvider loadItemForTypeIdentifier:(NSString *)kUTTypeImage options:nil completionHandler:^(UIImage *image, NSError *error) {
                if(image) {
                     dispatch_async(dispatch_get_main_queue(), ^{
                        [imageView setImage:image];
                        imageToScan = image;
                        [self scanImage:imageToScan];
                    });
                }
            }];

            imageFound = YES;
            break;
        }
    }

    if (imageFound) {
        // We only handle one image, so stop looking for more.
        break;
    }
}

我尝试在 Google 上进行大量搜索，但一无所获。我什至尝试了更改后的代码但没有用，这是更改后的代码:

                    itemProvider.loadItemForTypeIdentifier(kUTTypeImage as NSString, options: nil, completionHandler: { (image, error) in
                    if image != nil {
                        NSOperationQueue.mainQueue().addOperationWithBlock {
                            if let imageView = weakImageView {
                                var imageToSet: UIImage? = image as? UIImage
                                imageView.image = image as? UIImage
                            }

                            self.imageToScan = self.imageView.image
                            self.scanFromImage(self.imageToScan)
                        }
                    }
                })

更新:我注意到一件事；如果我创建一个新项目并向其添加一个 Action 扩展，除了我在 block 中添加的几行代码外，还会自动生成相同的代码。在这种情况下，即使没有更改一行自动生成的代码，imageView.image 也为零。这是swift中的错误吗？或者我的 Xcode 应用程序存在一些错误。

最佳答案

问题是图像不是UIImage，它是NSURL。

将代码改成这个:

imageView.image = UIImage(data: NSData(contentsOfURL: image as NSURL)!)!

关于ios - 无法在 swift iOS 8 扩展中转换 UIImage，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25887242/