Re: Custom attachment in a text view

FROM : Douglas Davidson
DATE : Tue Nov 06 23:09:28 2007

On Nov 6, 2007, at 1:59 PM, David Sinclair wrote:

> For the first problem, the recommended solution seems to be to 
> subclass NSTextView to override -readablePasteboardTypes, -
> writablePasteboardTypes, -readSelectionFromPasteboard:type:, etc to 
> add the new pasteboard type.  Which works, mostly, except my 
> implementation mangles the text if dragging a block of text 
> containing my custom attachment, as opposed to the attachment by 
> itself (which works fine).  I'm not sure how to handle the former 
> case.
>
> I haven't solved the second problem, of my custom attachments 
> vanishing when the text is saved to the data store.  Looking at the 
> NSTextStorage contents after inserting it, the attachment is there, 
> but it seems to be stripped out when saving (by encoding as data for 
> a binary Core Data attribute).  Inserting an image attachment is 
> saved correctly, though.  Which makes me think I need to encode the 
> attachment somehow, but an -encodeWithCoder: method in the cell 
> isn't called.  Do I need to create a temporary file and use a file 
> wrapper (the attachment currently passes nil for -
> initWithFileWrapper:)?  That didn't seem to help, but maybe I didn't 
> do it right.


Here's what I sent to this list in response to another question 
earlier today:

"The issue here has to do with the formats used to store text on the 
pasteboard.  Copy/paste can potentially take place between any two 
applications, so the pasteboard generally uses application-independent 
formats for the interchange of data.  In this case, attachments are 
stored for pasteboard purposes as file contents.  One option for you 
is to decide on a file format to represent the contents of your custom 
attachments, and use that as the contents of the file wrapper for copy/
paste purposes.  In this, you should consider what you want to happen 
when text is copied and pasted from your application to another 
application--is there some suitable representation for your custom 
attachments that other applications would understand?  Your 
application could then recognize these files by some means--by 
contents, or perhaps by extension--when they are pasted in, and 
substitute your custom attachment."

This would be applicable to your question about dragging or copy/
pasting a block of text containing your custom attachment.  Your 
second question is probably the same problem, since it has to do with 
the storage of text in persistent formats.

Douglas Davidson