core-data

问题 This question is about Core Data. I created a Entity called TV with three attributes called name , price and size . I also created a subclass of NSMutableObject with TV.h and TV.m files. I imported the TV.h to my DetailViewController.h which handles my sliders und UIElements I want to take the values of. So I did a fetch request, and everything works fine, BUT : Everytime I update the UISlider (valueDidChange:), Xcode creates a COPY of my entity and adds it to my TV-Object . All I want Xcode

问题 In my app I have a folder-file (one-to-many relationship).So when I open my app, my firstViewController contains all files and when clicked on each folder, it opens a tableViewController displaying files in that folder. Now here whenever I swipe any row, it is moved to bottom row and the table is update accordingly, the next swiped row will go and sit above the first swiped row. Eg, at present if my table contains 0 1 2 3 A B C D After swiping A 0 1 2 3 B C D **A** after swiping B 0 1 2 3 C D

问题 I am working on an iphone app that uses core data. The data includes large list of people. Each person will have certain attribues which are the same. First Name, Last Name, age and few more. Then these people will be divided into categories. The problem that i am having people who are in different categories will have different attributes. For example Person A will be in category A and will have attributes a,b,c Person B will be in category B and will have attribues b,c,d Person C will be in

问题 Could somebody point me in the correct direction for a full implementation example of NSManagedObjectContextObjectsDidChangeNotification NSManagedObjectContextDidSaveNotification and NSManagedObjectContextWillSaveNotification I have read the references to it here: http://developer.apple.com/library/ios/#documentation/cocoa/Reference/CoreDataFramework/Classes/NSManagedObjectContext_Class/NSManagedObjectContext.html but I don't see a full example code of exactly where I should implement it so

问题 Could somebody point me in the correct direction for a full implementation example of NSManagedObjectContextObjectsDidChangeNotification NSManagedObjectContextDidSaveNotification and NSManagedObjectContextWillSaveNotification I have read the references to it here: http://developer.apple.com/library/ios/#documentation/cocoa/Reference/CoreDataFramework/Classes/NSManagedObjectContext_Class/NSManagedObjectContext.html but I don't see a full example code of exactly where I should implement it so

问题 In my application, I observe the properties of a managed object. A change may lead to adjustments in some of its other properties, so the managed object itself receives a message of a changed property. These changes happen through bindings that are set up in the Interface Builder. I have the following method in the implementation of the managed object: -(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { if (

问题 In my application, I observe the properties of a managed object. A change may lead to adjustments in some of its other properties, so the managed object itself receives a message of a changed property. These changes happen through bindings that are set up in the Interface Builder. I have the following method in the implementation of the managed object: -(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { if (

问题 I'm trying to get all the attributes for an entity and then determine their type - I know I can do something on this line: if(![[thisAttribute attributeValueClassName] isKindOfClass:[NSString class]]) { but how do I check for a BOOL, Float or Integer? Here's my code so far: //get the attributes for this entity - we need to parse the dictionary of data we want to store and convert its contents from NSStrings to whatever type the entity requires NSEntityDescription* entity =

问题 For example if we hit "Stop" in XCode, it will close the app, mimicking the crash behaviour. But if my Core Data Context hasn't been saved, when I go back, the data won't be there. Are there any workaround for this? Should I save the context every time a big operation is finished? Thanks. 回答1: Based on my experience you should decide the right granularity when you use Core Data save mechanism. IMHO (maybe someone else could have different opinions) there is no standard to follow. My rule of

问题 Like the title says i have a one to many relationship and the many accepts numbers, and it is given an NSNumber, however when i retrieve that number back from coredata it comes in the form of a PFCachedNumber. Any thoughts on why this may be? Thanks! for (UserNumber *info in pinNumberArray) { //The numbers I'm after are inside ergTimes. NSSet *time = [[NSSet alloc] initWithSet:info.Times]; for (ErgTimes *ergTimes in time){ NSLog(@"Times Class : %@", [ergTimes.Twok class]); } } 回答1: I wouldn't