So I have been trying to use the MusicKit APIs for a few days now. I have been attempting to use the MPMusicPlayerApplicationController and MutableQueue APIs.
I have queue initialized already using setQueue(with: [String])
with an array of store identifiers for Apple Music songs. Then I want to allow the user to reorder the songs in the queue. I use the following code to attempt that.
let musicPlayerController = MPMusicPlayerController.applicationQueuePlayer
musicPlayerController.perform(queueTransaction: { queue in
let afterItem = queue.items.first(where: { $0.playbackStoreID == predecessorId })
let descriptor = MPMusicPlayerStoreQueueDescriptor(storeIDs: [newItemId])
queue.insert(descriptor, after: afterItem)
}) { (queue, error) in
// Completion for when items' position update
if error != nil {
print(error!)
}
}
The code above works as expected if afterItem
is nil (i.e. the song is correctly inserted at the front of the queue). However, if afterItem
is not nil, nothing happens. The queue stays the exact same as if no insert happened and there is no error provided in the completion handler. This problem happens regardless of whether the song being inserted is already in the queue or not.
Am I attempting modifying the queue incorrectly?
来源:https://stackoverflow.com/questions/50592820/mpmusicplayercontrollermutablequeue-insert-an-apple-music-song-not-working