如何快速从文档目录播放下一首曲目

Question

I make a simple media player. I have a UITableViewController with mp3 files from Document Directory and UIViewController which plays mp3 files. I pass NSURL of a mp3 file from UITableViewController to UIViewController and I can play it. I want to make buttons are which will be turn track to next or previous. How can I make it?

The code is passing NSURL on a specific file.

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    var playerVC = (segue.destinationViewController as! UINavigationController).topViewController as! PlayMusicViewController
    var indexPath = tableView.indexPathForSelectedRow()
    var nameOfObjectForPass = listOfMP3Files![indexPath!.row] // default it's name and
    var fileManager = NSFileManager.defaultManager()

    var wayToFile = fileManager.URLsForDirectory(NSSearchPathDirectory.DocumentDirectory, inDomains: NSSearchPathDomainMask.UserDomainMask)
    var passMusicFileURL: NSURL? // for pass mp3

    if let documentPath: NSURL = wayToFile.first as? NSURL {
        let musicFile = documentPath.URLByAppendingPathComponent(nameOfObjectForPass)
        println(musicFile)
        passMusicFileURL = musicFile
    }
    if segue.identifier == "listenMusic" {
        playerVC.nameMusicFile = nameOfObjectForPass // name
        playerVC.mp3URL = passMusicFileURL

        // test 
        playerVC.allUrlsVC = allURLS
    }

The code is playing mp3 file

    func playMusic() {
    AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback, error: nil) // == true
    AVAudioSession.sharedInstance().setActive(true, error: nil)
    var error: NSError?
    audioPlayer = AVAudioPlayer(contentsOfURL: mp3URL, error: &error)
   // audioPlayer.prepareToPlay()
    if currentPause == nil {
    } else {
        audioPlayer.currentTime = currentPause
    }
    //
    audioPlayer.volume = 0.5
    audioPlayer.play()
}

UPDATE

I made following

  var arrayMP3url: Array<AnyObject>!

    func playNextSound() {
        var queue = AVQueuePlayer(URL: mp3URL)
        var current = queue.currentItem

        var arrayForSearch = arrayMP3url as! [NSURL]

        var arrNS = arrayForSearch as NSArray

        var index = arrNS.indexOfObject(mp3URL!)
        println("index \(index)")

        println("array for search \(arrayForSearch)")

        println("current song \(current)")
    }

But I always get the same index from NSArray

Answer 1

Use your array of mp3 files, and determine current playing index using indexPath , increase or, decrease the current playing index on button click as Next, or, Prev , and change the mp3 file by the index. Replay the music.

Simple.

Ping if you need more help.

Update

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    var playerVC = (segue.destinationViewController as! UINavigationController).topViewController as! PlayMusicViewController

    var indexPath = tableView.indexPathForSelectedRow();

    //We only need to pass current index, and array of mp3 urls

    playerVC.curIndex=indexPath.row;
    playerVC.mp3s= listOfMP3Files;

}

So as described above, just declare two properties in your playerVC , ie

curIndex as int and mp3s as NSArray.

In the function

func playMusic() {

    var nameOfObjectForPass = mp3s![curIndex]; // default it's name and
    var fileManager = NSFileManager.defaultManager()

    var wayToFile = fileManager.URLsForDirectory(NSSearchPathDirectory.DocumentDirectory, inDomains: NSSearchPathDomainMask.UserDomainMask)
    var passMusicFileURL: NSURL? // for pass mp3

    if let documentPath: NSURL = wayToFile.first as? NSURL {
        let musicFile = documentPath.URLByAppendingPathComponent(nameOfObjectForPass)
        println(musicFile)
        passMusicFileURL = musicFile
    }

    self.nameMusicFile = nameOfObjectForPass // name
    self.mp3URL = passMusicFileURL

        // test 
    self.allUrlsVC = allURLS

   AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback, error: nil) // == true
    AVAudioSession.sharedInstance().setActive(true, error: nil)
    var error: NSError?
    audioPlayer = AVAudioPlayer(contentsOfURL: mp3URL, error: &error)
   // audioPlayer.prepareToPlay()
    if currentPause == nil {
    } else {
        audioPlayer.currentTime = currentPause
    }
    //
    audioPlayer.volume = 0.5
    audioPlayer.play()
}

Then simply define your next and previous index calculations like

func playNextSound(){
   self.curIndex++;
   var maxCount=self.mp3s.count-1;
   if(self.curIndex>maxCount){
         self.curIndex=maxCount;
   }

   playMusic();
}

func playPrevSound(){
   self.curIndex--;
   if(self.curIndex<0){
         self.curIndex=0;
   }

   playMusic();
}

Hope it helps. Cheers.