Bindings - registering change notification for multiple keys
Bindings - registering change notification for multiple keys
- Subject: Bindings - registering change notification for multiple keys
- From: dreamcat7 <email@hidden>
- Date: Tue, 1 Jul 2008 19:38:05 +0100
Hi,
I have my application's data and settings stored in 2 plist file, each
containing several/many keys.*
I would like to to save the changed items permanently in my data store
after the user interacts with the ui. Control elements are bound to a
settings NSDictionary in my data model.
For any bindings notifications, the following method
- (void)registerAsObserver
{
[model addObserver:self forKeyPath:@"prefs.debug"
options:(NSKeyValueObservingOptionNew |
NSKeyValueObservingOptionOld)
context:NULL];
}
will only register for observing one value at a time. However I may
have a wide variety of controls and settings that need to trigger the
same code to write out the dictionary to the plist file (or to any
arbitrary data storage mechanism i might use). And cant write anything
like @"prefs.*" because this syntax does not constitute a valid key-
path.
And if there is any way to listen for all values within a path or set.
So i am looking at other ways. Can you listen for all objects held by
an NSArray ? This might be a useful alternative.
Although probably very expensive to convert between NSDictionary <=>
NSArray each time an element was changed.
But i might try to change my data representation and avoid the
NSDictionary altogether.
Of course there is the method setKeys:
triggerChangeNotificationsForDependentKey: however i did find all the
explanations about this really difficult to follow. Awhile back i
tried doing with the apple example but unfortunately no luck. And
don't the array of triggering keys need to be first registered
individually anyway ? (perhaps thats why it failed to work for me).
Has anybody had successes with these or other method for multiple keys ?
*Note - no core data yet as i am a newbie and having core data in my
app would be alot do all at once.
But if this kind of issue is solved by a core data feature please let
me know.
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