Question

I’m trying to write a file using

writeToFile:atomically:YES

However, I`m not succesful with every file. When I’m trying to write a large array (created from four parsed XML documents), the file isn’t written (it does succeed when I’m trying to write an array containing only one parsed XML). And it also work, when I’m using

writeToFile:atomically:NO

What could be the reason of this kind of a behaviour? Is there a limit for file size when using
writeToFile:atomically:YES?

Answer 1

The only size limit is the amount of available space on the device. However, writeToFile:atomically: only works on an NSArray if every object, all the way down however many levels it goes, is a property list object. Property list objects are NSArray, NSDictionary, NSString, NSNumber, and NSData. Also, NSDictionary is only a property list object if the keys are all NSString.

NSArray does conform to NSCoding though, so if your custom class objects also conform to NSCoding then you could encode the array into an NSData and write that to a file– via NSKeyedArchiver.

Alternately, clean up your data structure so you’re only using property list objects.