Question

I have been trying to get the NSKeyedArchiver to write out my data in a human readable form (i.e. not as a binary file) I understand that I can use …

setOutputFormat: NSPropertyListXMLFormat_v1_0

But … I just can’t seem to get the syntax right, can anyone point me in the right direction?

NSData *artistData;

NSLog(@"(*) - Save All");
artistData = [NSKeyedArchiver archivedDataWithRootObject:artistCollection ];
[artistData writeToFile:@"/Users/fgx/Desktop/stuff" atomically:YES];

EDIT

I added setOutputFormat (see below) but I get a warning at compile, what am I missing?

warning: NSData  may not respond to 'setOutputFormat:'

Here is the code I used.

NSLog(@"(*) - Save All");
artistData = [NSKeyedArchiver archivedDataWithRootObject:artistCollection ];
[artistData setOutputFormat: NSPropertyListXMLFormat_v1_0];
[artistData writeToFile:@"/Users/fgx/Desktop/stuff" atomically:YES];

gary

Answer 1

This is what you have to do:

NSMutableData *data = [NSMutableData data];
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
[archiver setOutputFormat:NSPropertyListXMLFormat_v1_0];
[archiver encodeObject:artistCollection forKey:@"root"];
[archiver finishEncoding];
[data writeToFile:@"/Users/fgx/Desktop/stuff" atomically:YES];
[archiver release];

Note that you must use [archiver encodeObject:artistCollection forKey:@"root"] instead of [archiver encodeRootObject:artistCollection]; as suggested by Sean. This is because NSKeyedArchiver does not override NSCoder encodeRootObject: method. I consider this a bug and will report it to Apple.

Now, the real question is why do you want to write XML instead of the default binary format? If it’s for debugging purpose, I suggest you to use TextWrangler which will allow you to transparently edit binary plist files as if they were XML.