[英]Why am I getting a nil error?
目前,我可以在iPhone上將當前正在播放的歌曲添加到我的應用程序中,但是我正在嘗試根據應用程序上的歌曲名稱從Parse播放一首歌曲,但出現了nil錯誤。 為什么?
func playit(sender: UIButton!){
if let nowPlaying = musicPlayer.nowPlayingItem{
let title = nowPlaying[MPMediaItemPropertyTitle] as? String
let artist = nowPlaying[MPMediaItemPropertyTitle] as? String
println(title! + artist!)
let query = PFQuery(className: "Songs")
query.whereKey("SongName", equalTo: title!)
query.findObjectsInBackgroundWithBlock {
(objects: [AnyObject]?, error: NSError?) -> Void in
if error == nil {
// The find succeeded.
println("Successfully retrieved \(objects!.count) song(s).")
// Do something with the found objects
if let objects = objects as? [PFObject] {
for object in objects {
println(object.objectId)
let objects: PFObject = object as PFObject
let parseAudio: PFFile = objects.valueForKey("Songs") as! PFFile
let audioPath: String = parseAudio.url!
let urlParse: NSURL = NSURL(string: audioPath)!
player = AVPlayer(URL: urlParse)
println(player)
player.play()
}
}
} else {
// Log details of the failure
println("Error: \(error!) \(error!.userInfo!)")
}
}
}
}
不知道確切的錯誤是什么,我只能說您的問題很可能是在此塊中:
let objects: PFObject = object as PFObject
let parseAudio: PFFile = objects.valueForKey("Songs") as! PFFile
let audioPath: String = parseAudio.url!
let urlParse: NSURL = NSURL(string: audioPath)!
將parseAudio
轉換為NSURL
的字符串不會為媒體播放器獲取文件的內容。 嘗試這樣的事情:
let parseAudio: PFFile = objects.valueForKey("Songs") as? PFFile
parseAudio?.getDataInBackgroundWithBlock({ (data, error) -> Void in
if error == nil {
// do what you need to with the music file which is contained in `data`
let fullParseAudioFile = data
} else if error != nil {
println(error!.localizedDescription)
}
})
我沒有與媒體播放器一起工作,所以我不知道將數據轉換為哪種格式,但是現在您將擁有可用的文件,而不僅僅是代表文件名的字符串。
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