[iPhone] NSKeyedArchiver with NSValue Objects
I bashed into a problem with NSKeyedArchiver trying to encode NSValue objects. I am using NSValue to wrap up CGPoint and CGSize structures, then doing an encodeObject: forKey: to encode the NSValue. I get this message: [NSKeyedArchiver encodeValueOfObjCType:at:]: this archiver cannot encode structs' I poked around in CocoaBuilder and Google for some definitive answers, but the discussions appear to be mostly froth. This seems a little strange, as UIKit provides a bunch of NSValue additions to encode those CG structs, but the NSKeyedArchiver can't encode them. And the message is somewhat misleading: I'm encoding the NSValue object, not the structure . . .I'm assuming (I know, one should never assume) that the NSValue object is invoking that encodeValueOfObjCType:at: message . . . I'd like to get some clarification or definitive answers on what's going on . . . The available discussions I was able to find were not very helpful . . . In the meantime, for anybody else tripping over this, I worked around it by encodeObject: NSStringFromCGPoint(point) forKey: locationKey Cheers, . . . . . . . .Henry = iPhone App Development and Developer Education . . . Visit www.nonatomic-retain.com Mac OSX Application Development, Plus a Great Deal More . . . Visit www.trilithon.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: [iPhone] NSKeyedArchiver with NSValue Objects
On Dec 24, 2009, at 09:59, Henry McGilton (Boulevardier) wrote: I bashed into a problem with NSKeyedArchiver trying to encode NSValue objects. I am using NSValue to wrap up CGPoint and CGSize structures, then doing an encodeObject: forKey: to encode the NSValue. I get this message: [NSKeyedArchiver encodeValueOfObjCType:at:]: this archiver cannot encode structs' I poked around in CocoaBuilder and Google for some definitive answers, but the discussions appear to be mostly froth. This seems a little strange, as UIKit provides a bunch of NSValue additions to encode those CG structs, but the NSKeyedArchiver can't encode them. And the message is somewhat misleading: I'm encoding the NSValue object, not the structure . . .I'm assuming (I know, one should never assume) that the NSValue object is invoking that encodeValueOfObjCType:at: message . . . NSValue objects are not in suitable for archiving because there's no API contract that says they'll deal with byte ordering issues for you. (And, in fact, they couldn't, for structs in general.) If you're dealing with NSPoint and NSSize, you can use -[NSKeyedArchiver encodePoint/Size: forKey:], but you're crossing framework boundaries (a little bit) with CGPoint and CGSize, so you have an extra step. Either convert to NSPoint/NSSize and use the matching NSKeyedArchiver method, or encode the two structure components as numbers. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: [iPhone] NSKeyedArchiver with NSValue Objects
Also since you are crossing the boundaries of the framework to UIKit you could also use the NSStringFromCGRect/CGPoint and CGRect/CGPointFromNSString and encoding strings. Again you will have an extras step to go back and forth. --Waqar On Dec 24, 2009, at 12:47 PM, Quincey Morris wrote: On Dec 24, 2009, at 09:59, Henry McGilton (Boulevardier) wrote: I bashed into a problem with NSKeyedArchiver trying to encode NSValue objects. I am using NSValue to wrap up CGPoint and CGSize structures, then doing an encodeObject: forKey: to encode the NSValue. I get this message: [NSKeyedArchiver encodeValueOfObjCType:at:]: this archiver cannot encode structs' I poked around in CocoaBuilder and Google for some definitive answers, but the discussions appear to be mostly froth. This seems a little strange, as UIKit provides a bunch of NSValue additions to encode those CG structs, but the NSKeyedArchiver can't encode them. And the message is somewhat misleading: I'm encoding the NSValue object, not the structure . . .I'm assuming (I know, one should never assume) that the NSValue object is invoking that encodeValueOfObjCType:at: message . . . NSValue objects are not in suitable for archiving because there's no API contract that says they'll deal with byte ordering issues for you. (And, in fact, they couldn't, for structs in general.) If you're dealing with NSPoint and NSSize, you can use -[NSKeyedArchiver encodePoint/Size: forKey:], but you're crossing framework boundaries (a little bit) with CGPoint and CGSize, so you have an extra step. Either convert to NSPoint/NSSize and use the matching NSKeyedArchiver method, or encode the two structure components as numbers. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
