I have an NSMutableArray that contains NSMutableDictionary's. Each dictionary has an AVAsset, an NSURL, an NSString, and two UIImages. I want to save my array to disk so that each time I close and open my app, I can load the array and convert the URLs's to NSData objects in order to play audio and use the AVAssets for some other actions. I know I can save and load my array using initWithContentsOfFile and writeToFile:atomically and this answer is pretty informative: Saving a NSArray. However, that answer was from 2009. Is there a better way of saving and loading an array these days?.
1 Answer
As for the answer you linked, the answer is still valid. And according to it, you cannot store it the way it mentions. This is because array must be plist format compatible in order to be saved like that. When you parse your array down to lowest element hierarchy, you have UIImage which is just an object pointer and doesn't make sense.
One practical way would be store UIImages as separate files, and store their paths as part of your NSMutableDictionary objects. Same holds true for AVAssets. Off course you need to engineer the solution to fully accomplish this goal.
One more way to store non-plist compatible objects is to use archiving and unarchiving feature. Refer to the documentation. Here, make sure that each object in the tree follows protocol NSCoding (Probably, AVAsset in your question does not conform to it, so you need a way to work around it). For an example, see this answer and search the likes of it.
2 Comments
Brosef
What do you mean by saving
UIImages and AVAssets as separate files?
Nirav Bhatt
Do not store them in memory store them to disk and store their path within dictionaries. Later retrieve them from the disk.
writeToFilewill not work withAVAssetandUIImageobjects. Read the docs for that method.