problem writing a NSMutableArray to file in cocoa

Question

A real beginners question. I have a NSView subclass in which I create a NSMutableArray containing NSValues. When I want to write the array to a file using writetofile:atomatically: the file is created but it contains none of the NSValues that the mutable array does contain. Does anyone know how I successfully can write this mutable array to a file?

Thanks

Jesse Rusak · Accepted Answer · 2012-04-26T14:04:39.323

15

NSValues can't be saved in a plist (which is what writeToFile:atomically: does). Take a look here for the values you can save. (NSNumber is a kind of NSValue you can save, but other NSValues will fail.)

If you want to save your array with NSValues, you can use archiving instead of writeToFile:atomically:. NSArray and NSValue both support archiving, so you just convert the array to an archive and save that data to a file. (It will include the NSValues as well.) The code looks something like this:

[NSKeyedArchiver archiveRootObject:myArray toFile:@"myPath"];

To load it, just use:

NSArray *myArray = [NSKeyedUnarchiver unarchiveObjectWithFile:@"myPath"];

edited Apr 26 '12 at 14:04

answered Apr 15 '09 at 10:56

Jesse Rusak

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I used NSArchiver and NSUnarchiver instead and it works perfectly. Thanks – Apr 15 '09 at 12:15
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You're welcome. Note that NSKeyed[Un]Archiver is preferred over NS[Un]Archiver nowadays. – Jesse Rusak Apr 15 '09 at 12:17

problem writing a NSMutableArray to file in cocoa

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