MPMediaItem的发布日期返回Nil（迅速4）

Question

I am trying to get the realease year of songs in a music player but all I am getting is nil values returned. I've tried writing it every way I can think of and it always returns nil. I've found very little help on this except that it seems this is a known problem... This is the one resource I found that looks like it might help: Get album year for item in iPod library? but I believe this is objective C. My question is this. Does anyone know how to get the release date of MPMediaItems in Swift code? Or know how to translate the linked article to Swift language for me to try. Thanks a bunch!

func getYear() {
    let mediaQuery = MPMediaQuery.songs()
    for songs in mediaQuery.items! {
        print(songs.title)
        print(songs.releaseDate)
        print(((songs.value(forProperty: MPMediaItemPropertyReleaseDate)!))
        print(songs.getReleaseDate())
    }
}

extension MPMediaItem {
    @available(iOS 10.0, *)
    func getReleaseDate() -> Date? {
        return self.perform(#selector(getter: MPMediaItem.releaseDate))?.takeUnretainedValue() as! NSDate? as Date?
    }
}

Answer 1

I had the same problem and thanks to the resource you linked, I managed to solve it! I translated the Objective-C code to Swift 4 and it just works like a charm even on iOS 11 with Xcode 9, here's the code:

let yearNumber: NSNumber = item.value(forProperty: "year") as! NSNumber
if (yearNumber.isKind(of: NSNumber.self)) {
    let year = yearNumber.intValue
    if (year != 0) {
               // do something with year
    }
}