mpmediapickercontroller - 如何获取 MPMediaPlaylist 的用户定义封面图片和描述？

Question

我知道如何通过以下方式获得 MPMediaQuery 的标题:

MPMediaQuery *playlistsQuery = [MPMediaQuery playlistsQuery];

NSArray *items = [playlistsQuery collections];

MPMediaPlaylist *myPlaylist = items.firstObject;

NSLog(@"%@",myPlaylist.name); //"New playlist title"

有谁知道如何访问 MPMediaPlaylist 的封面和描述？

Screenshot - User created Playlist

Answer 1

获取描述很容易，只需使用

var descriptionText: String? { get }

来自 MPMediaPlaylist
要获取用户定义的图像，您必须使用私有(private) API，这是一个扩展，您可以使用它来获取存储在磁盘上的图像，或获取图像的 URL :

extension MPMediaPlaylist {
    /**
     User selected image for playlist stored on disk.
     */
    var userImage: UIImage? {
        guard let catalog = value(forKey: "artworkCatalog") as? NSObject else {
            return nil
        }

        let sel = NSSelectorFromString("bestImageFromDisk")

        guard catalog.responds(to: sel),
            let value = catalog.perform(sel)?.takeUnretainedValue(),
            let image = value as? UIImage else {
            return nil
        }
        return image
    }

    /**
     URL for playlist's image.
     */
    var imageUrl: URL? {
        if let catalog = value(forKey: "artworkCatalog") as? NSObject,
            let token = catalog.value(forKey: "token") as? NSObject,
            let url = token.value(forKey: "availableArtworkToken") as? String {
            return URL(string: "https://is2-ssl.mzstatic.com/image/thumb/\(url)/260x260cc.jpg")
        }
        return nil
    }
}

与往常一样，请记住，当 Apple 在后台更改内容或您的应用程序可能被 App Store 拒绝时，它可能随时停止工作。