Re: Triggering a Method when a Core Data Property is Altered.
Re: Triggering a Method when a Core Data Property is Altered.
- Subject: Re: Triggering a Method when a Core Data Property is Altered.
- From: Joshua Garnham <email@hidden>
- Date: Tue, 6 Oct 2009 23:32:51 -0700 (PDT)
Volker,
I have tried using the below code to add my self as an observer then trigger an action but it doesn't work.
- awakeFromNib {
[self addObserver: self
forKeyPath: @"name"
options: NSKeyValueObservingOptionNew
context: NULL];
}
-(id)init {
dispatch = [[NSDictionary dictionaryWithObjectsAndKeys:@selector(doSomething:),@"name", nil] retain];
}
...
- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
{
[self performSelector:msg withObject:object withObject:keyPath];
}
Is there something wrong that is blatantly obvious?
Cheers,
Josh.
________________________________
From: Volker in Lists <email@hidden>
To: Joshua Garnham <email@hidden>
Cc: email@hidden
Sent: Tuesday, 6 October, 2009 18:57:59
Subject: Re: Triggering a Method when a Core Data Property is Altered.
Josh,
depending on where you need to get a notification:
a) within the same NSManagedObject or a relationship: http://developer.apple.com/mac/library/documentation/Cocoa/Reference/Foundation/Protocols/NSKeyValueObserving_Protocol/Reference/Reference.html#//apple_ref/occ/clm/NSObject/keyPathsForValuesAffectingValueForKey:
b) in any other object: just register as observer as described in KVO basics: http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/KeyValueObserving/Concepts/KVOBasics.html
Take note: The triggering happens not on the change of the TextFieldCell in a table, but due to a property changing.
When you have looked into KVO - what have you tried already?
Cheers,
Volker
Am 06.10.2009 um 18:45 schrieb Joshua Garnham:
> Hi.
>
> I am trying to trigger a method when A Core Data property is changed, e.g A Text Fields Text in a Table (connected to Core Data) is changed. I have looked into Key Value Observing but haven't had much luck.
>
> Cheers.
>
>
>
>
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