Save list of CGPoints using NSUserDefaults

Question

I have a bunch of CGPoints from a CCTMXLayer I want to save to NSUserDefaults but cannot seem to figure out an elegant way of doing so.

Originally I was hoping to save an NSDictionary with an NSMutableSet for a value containing several NSValues (valueWithCGPoint). From what I can tell neither NSMutableSet or NSValue is supported by NSUserDefaults.

At this point I am considering saving the x&y values of the CGPoint as a string and just converting it back and forth as needed.

Have you considered just using an NSKeyedArchiver to a file? (Rather than using NSUserDefaults.) — John Parker, Jan 01 '11 at 21:52

score 48 · Accepted Answer · answered Jan 01 '11 at 22:10

48

There exists a pair of functions NSStringFromCGPoint and CGPointFromString. You can use these to produce an array of strings representing the points for serialization, and then convert back when you're finished.

answered Jan 01 '11 at 22:10

Lily Ballard

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Remarkable! I had no idea these functions existed. Always finding out new facets of objective-c. – Chris Daviduik Jan 01 '11 at 22:32

score 1 · Answer 2 · answered Jan 01 '11 at 21:56

1

Box them in NSValue objects. Once they're in there, you can write the NSValues out to disk (since they conform to <NSCoding>) or put them in NSUserDefaults or whatever.

answered Jan 01 '11 at 21:56

Dave DeLong

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This is exactly my problem. I am trying to store an NSArray (or NSSet...I have tried both) of NSValues using NSUserDefaults but keep receiving an error: [NSUserDefaults setObject:forKey:]: Attempt to insert non-property value – Chris Daviduik Jan 01 '11 at 22:06
Property lists don't use . NSValue objects cannot be written to plists. – Lily Ballard Jan 01 '11 at 22:09
Oh duh, sorry. Yes, you'll have to use an `NSKeyedArchiver` to convert the `NSValues` into `NSDatas` (or an `NSArray` into an `NSData`) – Dave DeLong Jan 01 '11 at 22:11

Save list of CGPoints using NSUserDefaults

2 Answers2