我已经成功地创建了一个上下一个排队系统,它工作得几乎完美。我可以移动,删除和添加歌曲到列表中没有任何问题我遇到的唯一问题是,当用户决定使用洗牌模式(例如MPMusicShuffleMode.songs)时,“上下一个”视图仍然显示旧顺序(假设洗牌模式设置为“关闭”)。应用程序Ecoute有一个类似的排队系统,但它也可以在洗牌时工作。
我意识到ecoute不使用MPMusicShuffleMode,如果在ecoute中按shuffle后进入stock music player,它将保持不变。我已经找到了一种显示无序歌曲正确顺序的方法(只需无序播放NSMutableArray并将其设置为新队列)真正的问题是,当用户想要“洗牌相册”时,我如何洗牌这个数组?如果有帮助,NSMutableArray包含MPMediaItem
非常感谢。
编辑:
这种尝试是有效的,但时间会随着歌曲的数量呈指数增长2000首歌大约花了25-35秒,非常慢。

else if(self.shuffleMode == "Songs"){
        self.shuffleMode = "Albums"
        self.shuffle.setTitle("Shuffle Albums", forState: UIControlState.Normal)
        var queueCopy = NSMutableArray(array: self.queue.items)
        var newQueue = NSMutableArray(array: [])

        var albums = MPMediaQuery.albumsQuery().collections as [MPMediaItemCollection]
        var albumsCopy = NSMutableArray(array: albums)
        shuffleArray(albumsCopy)

        for album in albumsCopy{
            for item in queueCopy{
                if (album.representativeItem!.valueForProperty(MPMediaItemPropertyAlbumTitle) as NSString == item.valueForProperty(MPMediaItemPropertyAlbumTitle) as NSString){
                    for(var i = 0; i < album.items!.count; i++){
                        if(album.items![i].valueForProperty(MPMediaItemPropertyTitle) as NSString == item.valueForProperty(MPMediaItemPropertyTitle) as NSString){
                            newQueue.addObject(item as MPMediaItem)
                        }
                    }
                }
            }
        }

        let newQueueToSet = MPMediaItemCollection(items: newQueue)
        let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
        appDelegate.currentQueue = newQueueToSet
        self.queue = newQueueToSet

        self.player.setQueueWithItemCollection(newQueueToSet)

}

编辑2:
设法把它降到8秒,但离Ecoute的1到2秒还差得远。
8秒版本:
        var albumNames = [String]()
        for item in queueCopy{
            albumNames.append(item.valueForProperty(MPMediaItemPropertyAlbumTitle) as NSString)
        }

        let unique = NSSet(array: albumNames).allObjects as [MPMediaItem]
        var uniqueAlbumNames = NSMutableArray(array: unique)
        shuffleArray(uniqueAlbumNames)

        for name in uniqueAlbumNames{
            for item in queueCopy{
                if item.valueForProperty(MPMediaItemPropertyAlbumTitle) as NSString == name as NSString{
                    newQueue.addObject(item as MPMediaItem)
            }
        }
}

最终编辑:
我坚持的最后一段代码。差不多3000首歌需要7-8秒。
    @IBAction func shufflePressed(sender: AnyObject) {

    if self.shuffleMode == "Off"{
        self.shuffleMode = "Songs"
        self.shuffle.setTitle("Shuffle All", forState: UIControlState.Normal)
        self.shuffle.setTitle("Shuffling", forState: UIControlState.Highlighted)


        var queueCopy = NSMutableArray(array: self.queue.items)
        self.unshuffledQueueCopy = self.queue

        shuffleArray(queueCopy)
        let newQueue = MPMediaItemCollection(items: queueCopy)
        let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
        appDelegate.currentQueue = newQueue
        self.queue = newQueue

        self.player.setQueueWithItemCollection(newQueue)

    }
    else if(self.shuffleMode == "Songs"){
        self.shuffleMode = "Albums"
        self.shuffle.setTitle("Shuffle Albums", forState: UIControlState.Normal)

        var queueCopy = NSMutableArray(array: self.queue.items)
        var newQueue = NSMutableArray(array: [])

        var albums = MPMediaQuery.albumsQuery().collections as [MPMediaItemCollection]
        var albumsCopy = NSMutableArray(array: albums)
        shuffleArray(albumsCopy)


        // Takes 8 seconds for 3000 songs

        var albumNames = [String]()

        for item in queueCopy{
            albumNames.append(item.valueForProperty(MPMediaItemPropertyAlbumTitle) as NSString)
        }

        let unique = NSSet(array: albumNames).allObjects as [MPMediaItem]
        var uniqueAlbumNames = NSMutableArray(array: unique)
        shuffleArray(uniqueAlbumNames)


        for name in uniqueAlbumNames{
            for item in queueCopy{
                if item.valueForProperty(MPMediaItemPropertyAlbumTitle) as NSString == name as NSString{
                    newQueue.addObject(item as MPMediaItem)
                }
            }
        }

        let newQueueToSet = MPMediaItemCollection(items: newQueue)
        let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
        appDelegate.currentQueue = newQueueToSet
        self.queue = newQueueToSet

        self.player.setQueueWithItemCollection(newQueueToSet)

    }
    else if(self.shuffleMode == "Albums"){
        self.shuffleMode = "Off"
        self.shuffle.setTitle("Shuffle", forState: UIControlState.Normal)
        var queueCopy = NSMutableArray(array: self.unshuffledQueueCopy.items)
        var nowPlayingItem = self.player.nowPlayingItem
        for(var i = 0; i < queueCopy.count; i++){
            if(queueCopy[i] as MPMediaItem == nowPlayingItem){
                self.fromIndex = i
            }
        }
        let newQueue = MPMediaItemCollection(items: queueCopy)
        let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
        appDelegate.currentQueue = newQueue
        self.queue = newQueue

        self.player.setQueueWithItemCollection(newQueue)
        self.fromItem = newQueue.items[fromIndex + 1] as MPMediaItem

    }

最佳答案

所以在伪代码中,它看起来像下面这样。
循环数组,仅生成相册的新数组
洗牌新相册数组
循环新相册数组,在原始数组中查找该相册中的项目。
在match上,将这些歌曲写入第三个数组,该数组将成为您的新播放列表。
谢谢

10-05 21:17
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