Cocoa NSDocument: getting autosave to work

问题:

Documentation simply states that setting setAutosavingDelay to anything > 0 on the shared doc controller should do it, but after calling

[[NSDocumentController sharedDocumentController] setAutosavingDelay:2.0];

in my controller, autosave doesn't seem to work: I neither see anything in ~/Library/Autosave Information/, nor is

[[[NSDocumentController sharedDocumentController] currentDocument] autosavedContentsFileURL]

initialized.

Note that in my app, normal loading and saving work fine (keyedarchivers, nscoding-based class for my docs, etc).

回答1:

Have you overridden -updateChangeCount: at all? I'm pretty certain that Apple's implementation is the code that starts up the autosave timer. Also, what if you experiment with a longer timer?

回答2:

Some people find that the directory ~/Library/Autosave Information is owned by root, and so files can not be written therein. See for example http://discussions.apple.com/thread.jspa?threadID=2252306

I don't know how the bug arises but I was bitten by it -- the directory was created 2010-06-17 12:19 and I assume that the permissions were wrong from that moment.