Re: Core Data in a framework ?

FROM : dreamcat7
DATE : Wed Sep 17 23:24:45 2008

Hi
I apologize if this topic has already been discussed elsewhere.
Nobody else has replied yet so perhaps can summarize more briefly the 
whole thing:


> NSMutableArray* dates;
> NSMutableArray* emails;
>
>     [self bind:@"dates" toObject:itemsController 
> withKeyPath:@"arrangedObjects.date" options:nil];
>     [self bind:@"emails" toObject:itemsController 
> withKeyPath:@"arrangedObjects.email" options:nil];



Why is a binding to arrayController.arrangedObjects.itemKey only a 1-
way binding?
Can i bind to the above keypath somehow bidirectionally ?

I understand i might use an entity relationship in core data to 
acheive a similar result.
If use Core Data, then can my class be part of a framework ?



> From: dreamcat7 <<email_removed>>
> Date: 17 September 2008 16:25:56 BST
> To: "Cocoa-Dev (Apple)" <<email_removed>>
> Subject: Binding to an NSArrayController however binding is 1-way 
> only.
>
>
> Hello,
>
> I am stuck finding a solution for my array of arrays problem. - A 
> problem with a twist !
>
> For the data must be displayed in an NSTableView and therefore it 
> must be structured in  a particular way.
> Mutable array of [items] with keypaths in each item making up the 
> columns of each row.
>
> NSArrayController  --[Points to]---->    NSMutableArray* items [of 
> type Item]  (*master array)
>
> Each Item ------>:         {
>                          NSDate* date,
>                                               NSString* email,
>                         float,
>                         NSMutableData,
>                         (id)context,
>                         etc...
>                     }
>
> Whole thing (apart from the tableview itself) Is housed within a 
> library class. That is to say a framework.
>
> I cannot expose my Items class to the outside world: it will almost 
> certainly have one or more hidden fields, the array of item is just 
> too unweildy and complicated to be used in the constructor function 
> for my class. At this point i would like to re0think my data design 
> however the real constraint is the NSTableView class because its 
> just so damn finnicky! NSTableView will only accept the one same 
> NSArrayController for all of its columns.
>
> So for my constructor function i bind flat representations to (some 
> of) the keys. Each column becomes its own NSMutableArray.
>
> NSMutableArray* dates;
> NSMutableArray* emails;
> etc...
>
>     [self bind:@"dates" toObject:itemsController 
> withKeyPath:@"arrangedObjects.date" options:nil];
>     [self bind:@"emails" toObject:itemsController 
> withKeyPath:@"arrangedObjects.email" options:nil];
>
> This means i can for a pretty standard array of objects (dates 
> emails contexts, etc.)  the client using my class can provide easily 
> the data needed into the constructor function. What could be simpler 
> than an array of NSString ?
>
> I understand that wich Core Data maybe the problem can be overcome 
> by specifying relationships (and more easily model differen view of 
> the data). However i cannot use Core Data because its for a library 
> class which must be packaged in a framework. Am i mistaken about 
> this - core data being unsuitable for use in a framework ?
>
>
> Looking at where i am stuck now, its with binding to my 
> arraycontroller at the keypath "arrangedObjects.date" and 
> "arrangedObjects.email". These rather special binding seems to be 
> only 1-way. If i put data into the items array (the master array) it 
> will appear in the dates. If i put data in the array of NSDate* 
> dates or NSString* emails then the array controller cannot do 
> anything. There may not be an items yet existing at that index !
>
> Continuing along my current road looks pretty rocky. Without the 
> extra help i need from the arrayController.
> This is how i am currently going about it:
>
> I observe the whole dates array, the emails array, and detect 
> whenever they change. If the original data in the master items array 
> is not the same (as the new dates array, or emails array).... I have 
> to check it wasnt simply because of the 1-ways binding,  (and if not 
> then find which date or email was added / removed / changed ). Then 
> must propagate the change back to the master array the missing data. 
> I got that all working however when the arrays are sorted then its 
> really a mess to figure out which object was what, and you can 
> imagine that any of the array can be sorted at any time...  Easily 
> an endless loop of changing, observing , and so it would be really 
> great to get out of that way of doing things.
>
>
> Is there a more straightforward method for representing such data 
> and to update with binding a sorted NSArrayController ?
> ( still remaining as a framework implementation and compatible with 
> nstableview ?? )
>
> Any help really appreciated thank you !
>
>