Core Data to UIDocument for iCloud

These slides are from a talk I did for CocoaHeads Belgium. I talked about how I moved my “B-list” shopping list app for iOS from Core Data to UIDocument for syncing lists with iCloud.

Transcript

1. iCloud It Just Works®
2. B-list structure
3. Current Version • Uses Core Data • No sync • No history
4. Model
5. • Key/Value • Core Data • Documents
6. Key/Value + - works well limited to 1MB not a good fit
7. Core Data + - good fit It Just Works, Sometimes®
8. Documents + - Like Dropbox not a good fit (for my app)
9. OS X System Preferences.app > iCloud > Manage...
10. Finder
11. iOS Settings.app > iCloud > Storage & Backup > Manage Storage
12. Documents folder Create a /Documents folder in the iCloud container. I you don’t store files in /Documents, you won’t see them individually.
13. UIDocument
14. UIDocument has a URL - (id)initWithFileURL:(NSURL *)url
15. UIDocument can read and write - (BOOL)loadFromContents:(id)contents ofType:(NSString *)typeName error:(NSError **)outError - (id)contentsForType:(NSString *)typeName error:(NSError **)outError id: NSData or NSFileWrapper
16. UIDocument has a life cycle - (void)saveToURL:(NSURL *)url forSaveOperation: (UIDocumentSaveOperation)saveOperation completionHandler:(void (^)(BOOL success))completionHandler - (void)openWithCompletionHandler:(void (^)(BOOL success))completionHandler - (void)closeWithCompletionHandler:(void (^)(BOOL success))completionHandler
18. UIDocument has autosave @property(retain) NSUndoManager *undoManager - (void)updateChangeCount:(UIDocumentChangeKind)change
19. About that URL... it can be local documentURL = [NSURL fileURLWithPath:NSHomeDirectory()]; or in iCloud documentURL = [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:nil]; → don’t call this on the main thread!
20. Local or iCloud?
21. Why in Settings?
22. Is this thing on? dispatch_async(dispatch_get_global_queue(...), ^{ NSFileManager *fm = [NSFileManager defaultManager]; ! ! url = [fm URLForUbiquityContainerIdentifier:nil]; }); iOS 6 NSFileManager *fm = [NSFileManager defaultManager]; id token = [fm ubiquityIdentityToken]; → you can call this on the main thread
23. Find out about updates
24. NSMetadataQuery _query = [[NSMetadataQuery alloc] init]; _query.searchScopes = @[NSMetadataQueryUbiquitousDocumentsScope]; _query.predicate = [NSPredicate predicateWithFormat:@"%K ENDSWITH '.blist'", NSMetadataItemFSNameKey]; [_query setNotificationBatchingInterval:0.5]; [_query startQuery]; → NSMetadataQueryDidFinishGatheringNotification → NSMetadataQueryDidUpdateNotification [[_query resultAtIndex:index] valueForAttribute:NSMetadataItemURLKey]; [_query disableUpdates]; [_query enableUpdates];
25. UIDocument → UIDocumentStateChangedNotification UIDocumentState state = doc.documentState; UIDocumentStateNormal UIDocumentStateInConflict UIDocumentStateEditingDisabled UIDocumentStateSavingError
26. Conflicts NSFileVersion *currentVersion = [NSFileVersion currentVersionOfItemAtURL:doc.fileURL]; NSFileVersion NSArray *conflictVersions = [[NSFileVersion unresolvedConflictVersionsOfItemAtURL:…] + (BOOL)removeOtherVersionsOfItemAtURL:(NSURL *)inFileURL error:(NSError **)outError @property (getter=isResolved) BOOL resolved @property(readonly) NSURL *URL
27. Coordinated file operations NSFileCoordinator [fc coordinateWritingItemAtURL:documentURL ! ! ! ! ! ! ! options:NSFileCoordinatorWritingForDeleting ! ! ! ! ! ! ! error:&error ! ! ! ! ! ! ! byAccessor:^(NSURL *newURL) { ! NSError *e; ! NSFileManager *fm = [[NSFileManager alloc] init]; ! BOOL success = [fm removeItemAtURL:newURL error:&e]; ! if (!success) { ! ! ... ! } }];
28. Demo
29. The End Steven Vandeweghe @bluecrowbar steven@bluecrowbar.com