Re: NSPopupButton and content values binding transformer
Re: NSPopupButton and content values binding transformer
- Subject: Re: NSPopupButton and content values binding transformer
- From: "email@hidden" <email@hidden>
- Date: Mon, 28 Oct 2013 13:09:02 +0000
On 26 Oct 2013, at 21:28, email@hidden wrote:
> On 25 Oct 2013, at 10:58, email@hidden wrote:
>
>> Value transformers applied to NSPopupButton have some idiosyncrasies.
>> http://stackoverflow.com/questions/12505764/nspopupbutton-bindings-with-value-transformer
>>
>> I have applied a transformer to an NSPopupButton content values binding but the IB configured transformer does not seem to be applied.
>> I am not alone in this: http://macscripter.net/viewtopic.php?id=39496
>>
>> If I log the binding the transformer is present.
>> However, if I enter an invalid transformer name the app does not raise (which it should).
>> If I then log the binding with the invalid name then it does raise.
>>
> The initial scenario was:
>
> 1. NSPopUpButton Content bound to arrayController.arrangedObjects
> 2. NSPopUpButton Content values bound to arrayController.arrangedObjects.name
> 3. A value transformer that returns NSString applied to the Content values binding.
>
> This initial scenario does indeed ignore the value transformer.
>
This one is a conversation with myself. However:
My adopted workaround to this is:
1. Remove the non functional transformer from the content values binding.
2. Define a category method on the objects returned by arrayController.arrangedObjects:
@implementation MyObject (MyCat)
- (NSString *)transName
{
return [self extValueForKey:@"name" withTransformerForName:@"MyTransformer"];
}
@end
3. Define the value for key transformer extension method:
@implementation NSObject (MyCat)
- (id)extValueForKey:(NSString *)key withTransformerForName:(NSString *)transformerName
{
return [[NSValueTransformer valueTransformerForName:transformerName] transformedValue:[self valueForKey:key]];
}
@end
4. NSPopUpButton Content values bound to arrayController.arrangedObjects.transName
This work around is compatible with the Content Objects and Selected Object bindings.
The approach is acceptable I feel for custom classes where a category method has limited scope.
I wouldn't want to utilise it in the case say of an NSDictionary binding.
Jonathan
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