【发布时间】:2020-04-03 00:34:54
【问题描述】:
在 Mac 上,触控栏可以自动检测正在播放音频的应用程序,并让您播放/暂停、跳过甚至搜索音频。这适用于 Spotify、Quicktime 甚至浏览器中的网站,例如 Google Chrome 上的 YouTube 标签。如何使用 Swift 获取相同的信息(歌曲名称、缩略图、正在播放歌曲的应用程序、时长等)?
【问题讨论】:
标签: objective-c swift macos cocoa
在 Mac 上,触控栏可以自动检测正在播放音频的应用程序,并让您播放/暂停、跳过甚至搜索音频。这适用于 Spotify、Quicktime 甚至浏览器中的网站,例如 Google Chrome 上的 YouTube 标签。如何使用 Swift 获取相同的信息(歌曲名称、缩略图、正在播放歌曲的应用程序、时长等)?
【问题讨论】:
标签: objective-c swift macos cocoa
macOS 与媒体播放器有更多的系统集成。例如,您可以向 Siri 询问当前歌曲或使用“今日正在播放”小部件:
所有这些集成都使用 Media Remote 私有框架中的私有 API。由于它是一个私有框架,如果您尝试在 Mac App Store 上提交它,Apple 将拒绝您的应用程序。您仍然可以对其进行公证,以便在 App Store 之外分发。
要使用该框架,您可以尝试以下操作:
// Load framework
let bundle = CFBundleCreate(kCFAllocatorDefault, NSURL(fileURLWithPath: "/System/Library/PrivateFrameworks/MediaRemote.framework"))
// Get a Swift function for MRMediaRemoteGetNowPlayingInfo
guard let MRMediaRemoteGetNowPlayingInfoPointer = CFBundleGetFunctionPointerForName(bundle, "MRMediaRemoteGetNowPlayingInfo" as CFString) else { return }
typealias MRMediaRemoteGetNowPlayingInfoFunction = @convention(c) (DispatchQueue, @escaping ([String: Any]) -> Void) -> Void
let MRMediaRemoteGetNowPlayingInfo = unsafeBitCast(MRMediaRemoteGetNowPlayingInfoPointer, to: MRMediaRemoteGetNowPlayingInfoFunction.self)
// Get a Swift function for MRNowPlayingClientGetBundleIdentifier
guard let MRNowPlayingClientGetBundleIdentifierPointer = CFBundleGetFunctionPointerForName(bundle, "MRNowPlayingClientGetBundleIdentifier" as CFString) else { return }
typealias MRNowPlayingClientGetBundleIdentifierFunction = @convention(c) (AnyObject?) -> String
let MRNowPlayingClientGetBundleIdentifier = unsafeBitCast(MRNowPlayingClientGetBundleIdentifierPointer, to: MRNowPlayingClientGetBundleIdentifierFunction.self)
// Get song info
MRMediaRemoteGetNowPlayingInfo(DispatchQueue.main, { (information) in
NSLog("%@", information["kMRMediaRemoteNowPlayingInfoArtist"] as! String)
NSLog("%@", information["kMRMediaRemoteNowPlayingInfoTitle"] as! String)
NSLog("%@", information["kMRMediaRemoteNowPlayingInfoAlbum"] as! String)
NSLog("%@", information["kMRMediaRemoteNowPlayingInfoDuration"] as! String)
let artwork = NSImage(data: information["kMRMediaRemoteNowPlayingInfoArtworkData"] as! Data)
// Get bundle identifier
let _MRNowPlayingClientProtobuf: AnyClass? = NSClassFromString("_MRNowPlayingClientProtobuf")
let handle : UnsafeMutableRawPointer! = dlopen("/usr/lib/libobjc.A.dylib", RTLD_NOW)
let object = unsafeBitCast(dlsym(handle, "objc_msgSend"), to:(@convention(c)(AnyClass?,Selector?)->AnyObject).self)(_MRNowPlayingClientProtobuf,Selector("a"+"lloc"))
unsafeBitCast(dlsym(handle, "objc_msgSend"), to:(@convention(c)(AnyObject?,Selector?,Any?)->Void).self)(object,Selector("i"+"nitWithData:"),information["kMRMediaRemoteNowPlayingInfoClientPropertiesData"] as AnyObject?)
NSLog("%@", MRNowPlayingClientGetBundleIdentifier(object))
dlclose(handle)
})
【讨论】:
MRMediaRemoteRegisterForNowPlayingNotifications 类型为@convention(c) (DispatchQueue) -> Void,然后使用NSNotificationCenter 订阅kMRMediaRemoteNowPlayingInfoDidChangeNotification 通知
class-dump 的工具可以从框架中转储头文件,但它只是 Objective-C 类(没有像我的答案中那样的 C 函数)。这个 repo 包含几乎所有最新版本的转储:github.com/w0lfschild/macOS_headers