Comments on: Making a Cocoa Application a QuickLook Consumer http://development.christopherdrum.com/blog/?p=109 Offering Public Transparency to the Development Process Wed, 07 Jul 2010 00:28:06 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Julien http://development.christopherdrum.com/blog/?p=109&cpage=1#comment-254 Julien Sun, 06 Jun 2010 13:36:11 +0000 http://development.christopherdrum.com/blog/?p=109#comment-254 "Perhaps I am exposing my programming naivety, but I don’t see why these methods were singled out as not being part of the DownloadItem class proper" DownloadItem is part of the model (following MVC conventions). The category appending -previewItemURL is exposing the Model side to View side so it makes sense to separate the two of them. You can reuse the model in other contexts while the -previewItemURL part is specific to Quick Look. "it seems that the datasource can also return an NSURL directly, rather than an intermediary object which will in turn send its own NSURL" From documentation: "NSURL QLPreview Additions": "This category implements the QLPreviewItem protocol which makes instances of NSURL suitable as items for the Quick Look preview panel". It is confirmed by framework "QLPreviewItem.h": @interface NSURL (QLPreviewConvenienceAdditions) [...] @end “Perhaps I am exposing my programming naivety, but I don’t see why these methods were singled out as not being part of the DownloadItem class proper”

DownloadItem is part of the model (following MVC conventions).

The category appending -previewItemURL is exposing the Model side to View side so it makes sense to separate the two of them. You can reuse the model in other contexts while the -previewItemURL part is specific to Quick Look.

“it seems that the datasource can also return an NSURL directly, rather than an intermediary object which will in turn send its own NSURL”

From documentation: “NSURL QLPreview Additions”: “This category implements the QLPreviewItem protocol which makes instances of NSURL suitable as items for the Quick Look preview panel”. It is confirmed by framework “QLPreviewItem.h”:

@interface NSURL (QLPreviewConvenienceAdditions)
[...]
@end

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