我遇到了一个奇怪的问题，我正在尝试构建一个操作扩展程序，它将从提供的图像中扫描条形码。以下是代码：
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，我可以看到已接收到一个图像。但是，当我尝试从该图像中获取UIImage时，它总是返回nil。以下是调试的屏幕截图，可能有所帮助。
更新：这里是接收到的图像的描述：
打印图像的描述：（NSSecureCoding！）图像= （instance_type = Builtin.RawPointer = 0x15d674c0 -> 0x32b6be5c（void *）0x32b6be70：NSURL）
我已经使用Objective C创建了相同的扩展程序，并且它可以工作，但在Swift中不起作用。以下是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;
}
}
我尝试在谷歌上搜索了很多内容，但是没有找到任何有用的信息。我甚至尝试了修改代码，但是仍然无法解决问题。以下是修改后的代码：
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：我注意到一个问题；如果我创建一个新项目并向其添加操作扩展，除了我在块中添加的几行代码之外，相同的代码会自动生成。即使没有改变自动生成的代码的任何一行，imageView.image 仍然为 nil。这是 Swift 的 bug 吗？还是我的 Xcode 应用程序有问题。