For anyone coming across this in the future, I just ran into this problem myself and it turned out that I was actually getting a stack overflow from a recursive function. Apparently calling setValue:forKey: on an NSObject calls the respective set[Key] function, where [Key] is the (capitalized) name you gave to the forKey section. So, … Read more
Before iOS 5 and OSX 10.7 scalar properties can’t be auto-generated and you had to add setter and getter implementations, which cause some penalty. Auto-generated properties are optimized. I’m not aware of any other penalties. Scalar and non-scalar properties are represented by the same types in DB, so there will be no change in DB’s … Read more
This is a common question here: “Core Data vs. SQLite for SQL experienced developers” “Core Data vs Sqlite and performance…” “Core Data vs sqlite3” “is it worth using core data for a simple sqlite app on the iphone with one table and no relationships or complicated subtable/views?” In summary, Core Data can greatly simplify your … Read more
First, having more than one NSManagedObjectContext on a single thread is not a standard configuration. 99% of the time you only need one context and that will solve this situation for you. Why do you feel you need more than one NSManagedObjectContext? Update That is actually one of the few use cases that I have … Read more
You need to build a Core Data stack, either within each method or in -setUp and then tear it down. Using an NSInMemoryPersistentStore will keep things fast and in-memory for your unit tests. Add a @property (nonatomic,retain) NSManagedObjectContext *moc to your TestCase subclass. Then: – (void)setUp { NSManagedObjectModel *mom = [NSManagedObjectModel mergedModelFromBundles:[NSArray arrayWithObject:bundleContainingXCDataModel]]; NSPersistentStoreCoordinator *psc … Read more
Yes – it is really that easy now (in iOS 5.0). For iOS 4 compatibility, the previous hurdles remain, but the documentation is not too bad on thread confinement. Maybe you should add this to a wiki section?
First of all, If you’re a registered iOS Dev, you should have access to the WWDC 2010 Sessions. One of those sessions covered a bit of what you’re talking about: “Session 117, Building a Server-driven User Experience”. You should be able to find it on iTunes. A smart combination of REST / JSON / Core … Read more
You can use the Codable interface with CoreData objects to encode and decode data, however it’s not as automatic as when used with plain old swift objects. Here’s how you can implement JSON Decoding directly with Core Data objects: First, you make your object implement Codable. This interface must be defined on the object, and … Read more
You will want to listen for the NSManagedObjectContextObjectsDidChangeNotification to pick up all changes to your data model. This can be done using code like the following: [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleDataModelChange:) name:NSManagedObjectContextObjectsDidChangeNotification object:myManagedObjectContext]; which will trigger -handleDataModelChange: on any changes to the myManagedObjectContext context. Your -handleModelDataChange: method would look something like this: – (void)handleDataModelChange:(NSNotification *)note { … Read more
NSString *_mySearchKey = @”James”; NSPredicate *_myPredicate = [NSPredicate predicateWithFormat:@”(firstname CONTAINS[cd] %@) OR (lastname CONTAINS[cd] %@)”, _mySearchKey, _mySearchKey];