在iOS中使用Mail扩展名共享Mail App中的附件

Question

现在，我正在开发应实现共享扩展以从Mail App共享附件的应用程序。 它应该支持不同的文件扩展名（几乎所有类型的文档）。 从Apple文档中，我了解到我必须在Info.plist中使用Predicate，但在SO的答案中，我发现我必须在代码中使用它。 现在，我一直坚持下去，无法继续进行下去。 这是我要在这篇文章中使用的谓词。

SUBQUERY (
            extensionItems,
            $extensionItem,
            SUBQUERY (
            $extensionItem.attachments,
            $attachment,

            (
                       ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "com.adobe.pdf"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.image"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.png"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.jpeg"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.jpeg-2000"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.tiff"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "com.compuserve.gif"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "com.microsoft.bmp"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "com.microsoft.word.doc"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "org.openxmlformats.wordprocessingml.document"
            )
).@count == $extensionItem.attachments.@count
).@count == 1

谁能在我的快速代码中建议如何使用此谓词：

    for attachment in content.attachments as! [NSItemProvider] {
        if attachment.hasItemConformingToTypeIdentifier(contentType) {

            attachment.loadItemForTypeIdentifier(contentType, options: nil) { data, error in
                if error == nil {
                    let url = data as! NSURL
                    if let fileData = NSData(contentsOfURL: url) {
                        self.selectedFile = NSData(data: fileData)
                    }
                } else {

                    let alert = UIAlertController(title: "Error", message: "Error loading file", preferredStyle: .Alert)

                    let action = UIAlertAction(title: "Error", style: .Cancel) { _ in
                        self.dismissViewControllerAnimated(true, completion: nil)
                    }

                    alert.addAction(action)
                    self.presentViewController(alert, animated: true, completion: nil)
                }
            }
        }
    }

这是我的NSExtensionActivationRule：

        <key>NSExtensionActivationRule</key>
        <dict>
            <key>NSExtensionActivationSupportsAttachmentsWithMaxCount</key>
            <integer>1</integer>
        </dict>

提前致谢。

Answer 1

所以最后我找到了问题的答案！ 以防万一有人遇到相同的问题。首先，我必须在Info.plist中使用PREDICATE语句（子查询），而不要使用键NSExtensionActivationSupportsAttachmentsWithMaxCount。 喜欢：

        <key>NSExtensionActivationRule</key>
        <string>SUBQUERY (
            extensionItems,
            $extensionItem,
            SUBQUERY (
            $extensionItem.attachments,
            $attachment,
            (
            ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "com.adobe.pdf"
            || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.image"
            || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.plain-text"
            || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.png"
            || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.jpeg"
            || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.jpeg-2000"
            || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.tiff"
            || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "com.compuserve.gif"
            || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "com.microsoft.bmp"
            || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "com.microsoft.word.doc"
            )
            ).@count == 1   // Important! to activate extension only on 1 chosen image
            ).@count == 1
        </string>

第二：使用必要的TypeIdentifier（UTI）正确获取所有附件：

    if let content = extensionContext!.inputItems.first as? NSExtensionItem {
        if let contents = content.attachments as? [NSItemProvider] {
            for attachment in contents{
                attachment.loadItemForTypeIdentifier("public.item", options: nil) { data, error in
                    let url = data as! NSURL
                    let fileExtension = url.pathExtension as String!
                    let fileName = self.generateImageName() as String
                    if let fileData = NSData(contentsOfURL: url) {
                        self.uploadFile("\(fileName).\(fileExtension)", data: fileData)
                    }
                }
            }
        }
    }

“ public.item” -是通用的UTI，用于支持NSExtensionActivationRule字符串中列出的所有文件扩展名。 您可以在https://developer.apple.com上获得必要的UTI。

祝您开发动作扩展好运！ 任何问题都欢迎！