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Je lis & en essayant l'exemple de code d'Apple sur le chargement des ressources vidéo.AVURLAsset loadValuesAsynchronously never fail
Mais je remarque que la fonction loadValuesAsynchronously sur AVURLAsset n'échoue jamais même si j'active le mode avion sur l'appareil ou désactiver le wifi sur mon mac. Quelqu'un sait dans quelle situation loadValuesAsynchronously ne parviendra pas à charger les clés?
Ceci est le parent sample code:
asset.loadValuesAsynchronously(forKeys: PlayerViewController.assetKeysRequiredToPlay) {
/*
The asset invokes its completion handler on an arbitrary queue.
To avoid multiple threads using our internal state at the same time
we'll elect to use the main thread at all times, let's dispatch
our handler to the main queue.
*/
DispatchQueue.main.async() {
/*
This method is called when the `AVAsset` for our URL has
completed the loading of the values of the specified array
of keys.
*/
/*
Test whether the values of each of the keys we need have been
successfully loaded.
*/
for key in PlayerViewController.assetKeysRequiredToPlay {
var error: NSError?
if asset.statusOfValue(forKey: key, error: &error) == .failed {
let stringFormat = NSLocalizedString("error.asset_%@_key_%@_failed.description", comment: "Can't use this AVAsset because one of it's keys failed to load")
let message = String.localizedStringWithFormat(stringFormat, title, key)
self.handleError(with: message, error: error)
return
}
}
// We can't play this asset.
if !asset.isPlayable || asset.hasProtectedContent {
let stringFormat = NSLocalizedString("error.asset_%@_not_playable.description", comment: "Can't use this AVAsset because it isn't playable or has protected content")
let message = String.localizedStringWithFormat(stringFormat, title)
self.handleError(with: message)
return
}
/*
We can play this asset. Create a new AVPlayerItem and make it
our player's current item.
*/
self.loadedAssets[title] = asset
let name = (thumbnailResourceName as NSString).deletingPathExtension
let type = (thumbnailResourceName as NSString).pathExtension
let path = Bundle.main.path(forResource: name, ofType: type)!
let thumbnail = UIImage(contentsOfFile: path)!
self.assetTitlesAndThumbnails[asset.url] = (title, thumbnail)
}
}