Re: Loading saved file into NSArrayController

FROM : Hans van der Meer
DATE : Mon Feb 18 21:18:01 2008

On 18 feb 2008, at 11:35, Mike Abdullah wrote:

> There is nothing technically wrong with doing this, but if you do so 
> every time the array is modified, your code will get rather messy 
> and quickly. Instead, just implement the standard array accessor 
> methods in your model:
>
> -insertObject:in<Key>AtIndex: and -removeObjectFrom<Key>AtIndex:
>
> As a result KVO notifications will be sent automatically, the 
> notifications will be better tuned to the actual changes, and you'll 
> end up with less code.


I did so but somehow implementing these this does NOT work for me!
Here is my code: -insertObject:in<Key>AtIndex: is in my class and is 
called inside a loop where successive solution objects are inserted in 
the solutions array. Is there something else I am missing?

- (void) insertObject:(id)anObject inSolutionsAtIndex:
(NSUInteger)anIndex; {
   [solutions addObject:anObject];
}

... <loop inserts solution objects>
   [self insertObject:solution inSolutionsAtIndex:0];
// the tableview does not update.

Besides, iff it worked there would be a kvo notification with every 
inserts, whereas I understand that bracketing will result in one 
notification only; please correct me if I am wrong here.

> On 18 Feb 2008, at 09:26, Hans van der Meer wrote

>> On 17 feb 2008, at 03:25, mmalc crawford wrote:

>>>
>>> On Feb 16, 2008, at 9:34 AM, Hans van der Meer wrote:
>>>

>>>> It might be of use to remember that changes within an 
>>>> NSMutableArray (addObject, remove...) do not by themselves lead 
>>>> tot calling the class's observers. I found it useful to bracket 
>>>> the changes in this manner:
>>>> [self willChangeValueForKey:@"theArray"];
>>>> // changes to the contents of the array
>>>> [self didChangeValueForKey:@"theArray"];
>>>>

>>> Don't do this.
>>> RTFineM.

>>
>> Please forgive me my ignorance. But I do not understand why the 
>> change bracketing should not be done. I have struggled a lot with 
>> updating a NSMutableArray bound in IB to an NSArrayController. It 
>> was (at least for me) impossible to get changes like addObject to 
>> be reflected in the coupled tableview UNLESS I bracketed the 
>> changes in the manner indicated above.
>>
>> I would gladly learn where I am erring. So please could you 
>> elaborate on this statement and indicate how then the coupling 
>> array-IBbinding-tableview can be effected.


Hans van der Meer