iOS:通过 UIActivityViewController 共享不适用于 UIActivityItemSource

Question

我想进一步自定义从我的应用程序共享内容的方式，而不是提供 UIActivityViewController带有图片和标题的使用 UIActivityItemSource协议(protocol)来实现提供此内容的方法。

所以我为我的模型创建了扩展 Scan像这样:

extension Scan: UIActivityItemSource {
    func activityViewControllerPlaceholderItem(_ activityViewController: UIActivityViewController) -> Any {
        return self.title as Any
    }

    func activityViewController(_ activityViewController: UIActivityViewController, itemForActivityType activityType: UIActivity.ActivityType?) -> Any? {
        return self.orderedDocuments.map({ $0.image }) as Any
    }

    func activityViewController(_ activityViewController: UIActivityViewController, thumbnailImageForActivityType activityType: UIActivity.ActivityType?, suggestedSize size: CGSize) -> UIImage? {
        return self.thumbnailImage
    }

    func activityViewController(_ activityViewController: UIActivityViewController, subjectForActivityType activityType: UIActivity.ActivityType?) -> String {
        return "Scan from: \(String(describing: self.created))"
    }
}

但是当我通过 Scan 的实例时到 UIActivityViewController它打开但它是空的。我看不到标题、预览或实际图像。这些方法被调用。

我正在介绍 UIActivityViewController像这样，因为没有太多可定制的:

func share(_ scan: Scan) {

        let shareController = UIActivityViewController(activityItems: [scan], applicationActivities: nil)

        present(shareController, animated: true)
}

Scan是核心数据实体，但我尝试创建单独的类只是为了共享，但这也不起作用。

编辑 :所以我在元数据方面取得了一些进展:

func activityViewControllerLinkMetadata(_ activityViewController: UIActivityViewController) -> LPLinkMetadata? {
        guard let image = self.orderedDocuments.first?.image else { return nil }
        let imageProvider = NSItemProvider(object: image)
        let metadata = LPLinkMetadata()
        metadata.imageProvider = imageProvider
        metadata.title = title
        return metadata
    }

它至少显示正确的标题和缩略图。我见过一些应用程序甚至显示字幕和文件大小，我猜这对于内存中的图像是不可能的？

我仍然无法共享一张以上的图片。

我更新的事件 Controller 方法:

func activityViewController(_ activityViewController: UIActivityViewController, itemForActivityType activityType: UIActivity.ActivityType?) -> Any? {
        return self.orderedDocuments.first?.image
    }

    func activityViewController(_ activityViewController: UIActivityViewController, dataTypeIdentifierForActivityType activityType: UIActivity.ActivityType?) -> String {
        return kUTTypePNG as String
    }

Answer 1

关于:

I have seen some apps even displaying subtitle and file size which I guess is not possible for in-memory images?

这很愚蠢，但可以通过以下方式完成:

linkMetaData.originalURL = URL(fileURLWithPath: "Insert whatever info here")

例如，对于这样的结果(自定义缩略图、自定义标题和带有文件大小的副标题):



...代码是:

func activityViewControllerLinkMetadata(_ activityViewController: UIActivityViewController) -> LPLinkMetadata? {

    let linkMetaData = LPLinkMetadata()

    // Thumbnail
    linkMetaData.iconProvider = NSItemProvider(object: someValidUIImage)

    // Title
    linkMetaData.title = "Ohay title!"

    // Subtitle with file size
    let prefix = "PNG Image"

    let fileSizeResourceValue = try! someValidURL.resourceValues(forKeys: [.fileSizeKey])
    let fileSizeInt = fileSizeResourceValue.fileSize

    let byteCountFormatter = ByteCountFormatter()
    byteCountFormatter.countStyle = .file
    let fileSizeString = byteCountFormatter.string(fromByteCount: Int64(fileSizeInt))

    let suffix = "・\(fileSizeString)"

    //👇
    linkMetaData.originalURL = URL(fileURLWithPath: "\(prefix)\(suffix)")

    return linkMetaData
}