Dear Roland, Thanks for the reply. That provides food for thought. One thing I should have mentioned is that I'm talking about an OS X app, not iOS. My impression so far is that Apple wants us to have iCloud enabled in the app, or not, but it should not be a user configurable thing. Perhaps I'm wrong (I hope so). I haven't seen any real-world iCloud enabled shoe-box apps on OS X yet, so it's hard to know what's the current best practice.
Cheers, Martin >> Dear list, >> >> I'm wondering about whether or not an app that uses iCloud to sync a >> core-data store (shoe-box app) should have a user preference to disable >> syncing. Suppose the user doesn't want to sync across machines? I don't >> think they get a check-box in the iCloud system prefs pane, right? >> >> And if it would be good practice to offer should a check-box to the user in >> the app's preferences, how would one go about enabling/disabling iCloud at >> run-time for an app using core data? Would it be enough to ignore the >> notifications? I guess not, since when the app relaunches it will see the >> transactions produced on other machines. So I guess the correct way is to >> create a new persistent store coordinator with/without the *Ubiquitous* keys >> and swap it in. >> >> And suppose the user has iCloud enabled in the app on one machine, but >> disabled on another machine, then the transaction logs would be generated. >> So how to ignore them on the machine where iCloud is disabled for the app? >> Would it be correct to create an NSPersistentStoreCoordinator where >> NSPersistentStoreUbiquitousContentNameKey and >> NSPersistentStoreUbiquitousContentURLKey are not set? Would that mean that >> that copy of the app would not get the >> NSPersistentStoreDidImportUbiquitousContentChangesNotification notifications >> and would it ignore the transaction logs? And what should one do when/if the >> user re-enables iCloud sync? Will the app catch up with the transactions? >> >> Has anybody thought about, or even better, solved these issues? >> >> Best wishes, >> >> Martin >> > > I'm finishing up a shoebox app now and I do have the option to store things > in iCloud or not. My eventual solution to this was to have a preference > screen in the app with a single "enable iCloud' switch. If you flip it from > off to on, or on to off, you get a section of buttons to hit asking how you > want to perform the transition (eg when transitioning to the cloud you can > merge local to cloud, use cloud or use local), it then gives you a > confirmation box before you do it. I failed to find a really good way to do > this in preferences, so I put it in the app itself, there are just too many > questions about how you want to perform the migration which I think need to > be asked then. > > Not quite sure about your question about iCloud on one device and not the > other. If iCloud is enabled then the files are in the iCloud URL sandbox, > else they are in the Documents subdirectory of your normal app sandbox. I > don't know what happens if you work in the sandbox without an > NSPersistentStoreUbiquitousContentNameKey and .. the other one .. I guess you > don't generate the logfiles and that may mean it's hard to later sync to the > cloud (unless makeUbiquitous is very smart). So I would personally probably > just use the same keys whether I was in iCloud or not and let the framework > sort it out. Yes I know that means if you stay local you might end up with > lots of useless logfiles you don't really need, I've seen no guidance in the > docs nor the forums about this. > > I'm not sure about the last question. I've been operating on the principle > that if you enable iCloud, anything which is there is there, and anything > local is either copied to a new URL and left there, or just overwritten, in > the general case it would seem hard to apply the transaction logs to a > database which might have moved forwards in time. > > I have found that writing a monitoring app which just shows the changes in > iCloud on the device has been the most useful debugging tool I have. I change > them in one place and can see on say an iPad what has happened in the cloud. > It continues to be unfortunate that the simulator doesn't work with iCloud > and you have to do it on the device as you just don't have the sandbox access > to really see what you have. > > > >> >> >> >> >> _______________________________________________ >> >> Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) >> >> Please do not post admin requests or moderator comments to the list. >> Contact the moderators at cocoa-dev-admins(at)lists.apple.com >> >> Help/Unsubscribe/Update your Subscription: >> https://lists.apple.com/mailman/options/cocoa-dev/rols%40rols.org >> >> This email sent to r...@rols.org > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Martin Hewitson Albert-Einstein-Institut Max-Planck-Institut fuer Gravitationsphysik und Universitaet Hannover Callinstr. 38, 30167 Hannover, Germany Tel: +49-511-762-17121, Fax: +49-511-762-5861 E-Mail: martin.hewit...@aei.mpg.de WWW: http://www.aei.mpg.de/~hewitson ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. 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