RE: Table sort image question
RE: Table sort image question
- Subject: RE: Table sort image question
- From: "Jon C. Munson II" <email@hidden>
- Date: Tue, 6 Jan 2009 14:57:18 -0500
- Organization: JTA Enterprises LLC
Thanks for that correction.
I created a subclass of an NSArrayController (which provides the data from a
CoreData entity to the table) and implemented the method in the subclass.
At first I had a little trouble, then, after scanning the ref you sent, I
set the dataSource outlet for the tableView to the NSArrayController (which
I wasn't sure if I needed to do or if it would "break" anything), and it
seems to work just peachy.
One more follow-on question: if one is using an NSArrayController to
provide data to tableView columns, is it wise to set the dataSource outlet
to that controller or does doing so create unnecessary overhead?
Peace, Love, and Light,
/s/ Jon C. Munson II
-----Original Message-----
From: Andy Lee [mailto:email@hidden]
Sent: Tuesday, January 06, 2009 2:31 PM
To: email@hidden
Cc: 'Graham Cox'; 'cocoa dev'
Subject: Re: Table sort image question
On Jan 6, 2009, at 2:18 PM, Jon C. Munson II wrote:
> OK, I looked into the method:
>
> - (void) tableView:(NSTableView*) aTableView
> sortDescriptorsDidChange:
> (NSArray*) oldDescriptors
>
> And decided to give it a shot after much play with the prior
> method. In
> that prior method I found that the sortDescriptors and Prototype
> were not
> getting changed as expected, thus my use of those items wasn't valid.
> Certain values in the descriptors weren't changing as expected.
>
> So, I created a subclass of NSTableView to implement the method above.
>
> I found that sortDescriptorsDidChange is not getting called.
You are supposed to implement the above method in the table view's
*data source*.
<http://developer.apple.com/DOCUMENTATION/Cocoa/Conceptual/CocoaFundamentals
/CommunicatingWithObjects/chapter_6_section_4.html
>
The full name of the method is tableView:sortDescriptorsDidChange:.
It takes two arguments, the first being the table view whose sort
descriptors changed.
--Andy
>
>
> I am not able to find any further reference to implementation of
> that method
> to make sure I implemented it correctly.
>
> My subclass isn't complicated, essentially containing a pointer to
> the view
> which needs to stay in sync with the table (so I can call a method
> to update
> the sortDescriptors for the underlying data), and the method above.
>
> Did I miss something? Based on what I see, I think the
> sortDescriptors
> aren't even being used when the column sort happens...or is that wrong
> thinking?
>
> Thanks in advance!
>
> Peace, Love, and Light,
>
> /s/ Jon C. Munson II
>
> -----Original Message-----
> From: Jon C. Munson II [mailto:email@hidden]
> Sent: Tuesday, January 06, 2009 10:09 AM
> To: 'Graham Cox'
> Cc: 'cocoa dev'
> Subject: RE: Table sort image question
>
>
> On 7 Jan 2009, at 12:18 am, Jon C. Munson II wrote:
>
>> 1. When is didClickTableColumn actually called? Is it after the
>> table does
>> its stuff, including setting the sort descriptors, or just prior to
>> that?
>
>
> This is not the method you want. You want the NSTableDataSource
> method:
>
> - (void) tableView:(NSTableView*) aTableView
> sortDescriptorsDidChange:
> (NSArray*) oldDescriptors
>
> In this method, you can retrieve the *current* sortDescriptors from
> the tableview, and sort a mutable array using:
>
> - (void) sortUsingDescriptors:(NSArray*) sortDescriptors
> [Jon C. Munson II] Thank you for this, I'm looking into it now.
>
> Note that the sort descriptors passed in the first method are the old
> ones, not the current ones, so you have to go back to the table to get
> the new ones. Having sorted the array, you need to reload the table to
> display the outcome. That's all - there's nothing else you need to do
> to support sorting from table columns except setting up the sort key
> and selector in IB.
>
> [Jon C. Munson II] OK. Thank you for that. I decided to stick with
> the
> delegate method of didClickTableColumn as it functionally provides
> the same
> thing (at this time) without having to create yet another class,
> instantation, etc. I will keep that in mind for future use though,
> so I
> appreciate the pointer to it.
>
>> 2. In attempting to answer #1, I ran into an issue with using the
>> -ascending message. The doc states its returns a bool, however, I
>> could not
>> use the message. Any ideas there?
>
> I don't see any reason to actually try and access the sort descriptor
> itself - just use it as a black box. Note that sort descriptors come
> in an array, so there could be several, one for each sortable column.
> I can't see immediately in the docs what order they come in, so you
> can't necessarily tell which sort descriptor represents a particular
> column (though my *guess* is that the first one is the selected column
> header).
>
>
> [Jon C. Munson II] I found in subsequent testing that
> didClickTableColumn
> appears to get called after the table sets its sort descriptors,
> etc. So,
> as you pointed out, I didn't need to do anything really with the sort
> descriptor other than "pass it along." Now, I've got to unhook the
> sortKeys
> in my hack of covertflow and use the sort descriptor as passed.
> Adapt and
> overcome....
>
> Thank you for your help so far.
>
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