Hi again Graham,
I have taken some time to work on your suggestions...unfortunately I still
can't figure out how to uncheck/recheck the checkboxes by clicking on them. :-(
I understand what you're telling me about keeping 2 lists and ultimately I
will get to the point where I have to do something with the items being
displayed in my table. But for now I'm still stuck on the checkboxes. This
was your last example code with my own variables/comments:
- (void) tableView:(NSTableView*) tv setObjectValue:(id) val
forTableColumn:(NSTableColumn*) aTableColumn row:(NSInteger) rowIndex
{
id object = [filenames objectAtIndex:rowIndex]; //filenames is my NSArray
of filenames
if([[aTableColumn identifier] isEqualToString:@"column2"]) //column2 is
the identifier for my checkbox column
{
BOOL selected = [val boolValue];
// add or remove the object from the selection set
if( selected )
//how can I uncheck the checkbox??? every method i'm trying fails...
[self addToSelection:object];
else
//how can I recheck the checkbox??? every method i'm trying fails...
[self removeFromSelection:object];
}
}
In this method it's so easy:
- (id)tableView:(NSTableView *)aTableView
objectValueForTableColumn:(NSTableColumn *)aTableColumn
row:(NSInteger)rowIndex
{
if ([[aTableColumn identifier] isEqualToString:@"column2"])
{
return [NSNumber numberWithInt:NSOnState]; //initializes checkbox
column with boxes all checked
}
return [filenames objectAtIndex:rowIndex];
There's one more thing...in your first email you said I needed to set something
in IB and at this point the only thing I have set is the column identifier for
this checkbox column (column2). If there is something else I need to set in IB
I'm not sure where to set it? I'm not using bindings at this time...
Thank you for your patience Graham. Ultimately I would have my list of files
in the first column and this would not change. Then checkboxes in the second
column which would start all checked. Then the user could uncheck/recheck any
boxes they choose and when it comes to processing time only the files that have
a checked box will be acted upon. I might be going about it the wrong way but
I was just trying to get the checkbox issue working first...thanks again!
Rick
________________________________
From: Jo Phils <jo_p...@yahoo.com>
To: Graham Cox <graham....@bigpond.com>
Cc: cocoa-dev@lists.apple.com
Sent: Friday, March 20, 2009 11:19:46 PM
Subject: Re: NSTableView updating checkboxes
Thank you again Graham so much for the quick reply. Yes you're right about
where I'm headed. I was just thinking that I could code it that when you click
on the checkboxes the state would toggle then when I got to the processing step
I would simply read the state and know how to process each item in my array.
But I see what you're saying yes at this point I have no set boolean state in
my array. I was able to initialize my table view with "checked" boxes by
returning the ON state but in this method I got stuck because the return is
void and that's where my problem was. Ok I will work on your suggestion and I
really do appreciate all of the help... :-)
I'll let you know,
Rick
________________________________
From: Graham Cox <graham....@bigpond.com>
To: Jo Phils <jo_p...@yahoo.com>
Cc: cocoa-dev@lists.apple.com
Sent: Friday, March 20, 2009 8:56:23 PM
Subject: Re: NSTableView updating checkboxes
On 20/03/2009, at 8:53 PM, Jo Phils wrote:
> Hi Graham and thank you very much for your reply. I think I'm still a bit
> confused I do apologize. :-( Here's my code so far so you can see...
>
> - (int)numberOfRowsInTableView:(NSTableView *)aTableView
> {
> return [filenames count];
> }
>
>
> - (id)tableView:(NSTableView *)aTableView
> objectValueForTableColumn:(NSTableColumn *)aTableColumn
> row:(NSInteger)rowIndex
>
> {
> if ([[aTableColumn identifier] isEqualToString:@"column2"])
> {
> return [NSNumber numberWithInt:NSOnState];
> }
> return [filenames objectAtIndex:rowIndex];
>
>
> - (void)tableView:(NSTableView *)aTableView
> setObjectValue:(id)anObject
> forTableColumn:(NSTableColumn *)aTableColumn
> row:(int)rowIndex
> {
> // This is where I'm stuck!
> }
>
> And in this code I am using my variable which is a list of filenames...
>
> NSMutableArray *filenames;
>
>
> Other than the connections I have in IB I have given this column of
> checkboxes the Identifier "column2" in IB. I have not set any other property
> key like you mentioned and I'm not sure where I would do that? I'm not using
> bindings in my case...I was under the impression it was not necessary? The
> first 2 methods seem to work fine and the 3rd method is being called but it's
> just I couldn't figure out the code to change the state of the checkboxes...
>
> Thank you again so much for your help,
>
Well, I guess what isn't clear is what the checkboxes actually *mean*. If your
data model is simply a list of strings (as it appears to be, even though they
represent filenames) then what is the boolean property?
If what you're after is to represent some subset of the list, i.e. "all the
checked filenames", then there are two basic ways to handle this. One is to
define a class that has both the filename and the 'checked' state as
properties, and keep an array of those. The better way (IMO) is to have two
lists - the original list "all filenames", and a second list "those which are
checked". The second approach has numerous advantages, such as being able to
quickly iterate the list or pass it to other processing methods as an object in
its own right (otherwise everything would have to iterate the main list looking
for those objects that have the 'checked' property set - this way they can just
get to work on that list as it comes).
The second approach is possibly a teeny bit more work, but well worth it. Your
controller will have two lists - the main list - an array of filenames, and a
second list - those that are checked. I'd recommend using NSMutableSet for the
second, since there's not really an inherent order to be concerned with here,
and it ignores double entries, etc. If you need a sorted list, it's easy to
generate one from the set on the fly.
The basic idea is that when a box is checked, the object is added to the set.
When unchecked, it is removed.
Some example code that shows the general idea (warning, typed into mail from
memory of the APIs involved)
@interface MyListController : NSObject
{
NSArray* mainList;
NSMutableSet* selectedObjects;
}
- (void) addToSelection:(id) object;
- (void) removeFromSelection:(id) object;
- (NSSet*) selection;
@end
//-------------------------------------------
@implementation MyListController
// much stuff glossed over, such as initialising the lists
- (void) addToSelection:(id) object
{
[selectedObjects addObject:object];
}
- (void) removeFromSelection:(id) object
{
[selectedObjects removeObject:object];
}
- (NSSet*) selection
{
return selectedObjects;
}
// as a NSTableDataSource
- (NSInteger) numberOfRowsInTableView:(NSTableView*) tv
{
return [mainList count];
}
- (id) tableView:(NSTableView*) tv
objectValueForTableColumn:(NSTableColumn*) aTableColumn row:(NSInteger) rowIndex
{
id object = [mainList objectAtIndex:rowIndex];
// if the object is in the set, it's checked, otherwise not
if([[aTableColumn identifier] isEqualToString:@"checked"])
return [NSNumber numberWithBool:[selectedObjects isMember:object]];
else
return object;
}
- (void) tableView:(NSTableView*) tv setObjectValue:(id) val
forTableColumn:(NSTableColumn*) aTableColumn row:(NSInteger) rowIndex
{
id object = [mainList objectAtIndex:rowIndex];
if([[aTableColumn identifier] isEqualToString:@"checked"])
{
BOOL selected = [val boolValue];
// add or remove the object from the selection set
if( selected )
[self addToSelection:object];
else
[self removeFromSelection:object];
}
}
Is that any help? If this isn't what you're trying to do, you'll need to be
more explicit about what your boolean property represented by the checkbox
actually is.
--Graham
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