KVO and Coredata/Undo Clarification
KVO and Coredata/Undo Clarification
- Subject: KVO and Coredata/Undo Clarification
- From: email@hidden
- Date: Wed, 15 Mar 2006 18:27:05 -0800
Hi List.
If I have an attribute called "foobared" thats just a bool, and is
transient, if I called [self willChangeValueForKey:@"foobared"] [self
didChangeValueForKey:@"foobared"] 5 times, with that result in 5
undo's in the stack even if there was no change, or does
NSPersistenDocument know to record changes only to a variable if its
core data (not a custom ivar) value changed?
As a real example, I have an object where its binary data is kept in
a child object.
So I have two objects: Binary and Data, Data actually holds the
binary info, and Binary holds other information, such as its name,
data type etc.
Binary <---> Data
Here is how I set the value from Binary to Data:
- (void)setValue:(NSData *)value
{
[self willChangeValueForKey: @"value"];
[[self valueForKey:@"data"] setValue: value forKey: @"value"];
[self didChangeValueForKey: @"value"];
}
And retrieve it:
- (NSData *)value
{
NSData * tmpValue;
[self willAccessValueForKey: @"value"];
tmpValue = [[self valueForKey:@"data"] valueForKey: @"value"];
[self didAccessValueForKey: @"value"];
return tmpValue;
}
Is this the right way, I'm especially worried about the setValue
method because it creates two change notifications..... because
Binary basically "hides" the Data object.
Is this something to be worried about? Should I be using
primitiveValueForKey??
Any help is of course appreciated.
Andre
email@hidden
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