CoreData: nil is not a legal NSManagedObjectContext parameter - ios

I am very new to Core Data and have been trying to following many tutorials, but most of them put all of the Core Data methods into AppDelegate. I have read that it is better to stay away from AppDelegate and use a custom Data Model class to manage these methods.
I have created a custom class to manage all of my data named MyDataModel. I implemented the boiler plate Core Data code. In one of my view controllers I have a simple method to implement some data using Core Data:
- (void)getProfile {
/*
* getProfile
*/
NSLog(#"%#", _Model.managedObjectContext);
Users *user = (Users *)[NSEntityDescription insertNewObjectForEntityForName:#"Users" inManagedObjectContext:_Model.managedObjectContext];
// Set Data
[user setValue:#"John" forKey:#"fname"];
[user setValue:#"Smith" forKey:#"lname"];
NSError *error;
[_Model.managedObjectContext save:&error];
}
The code from the header file:
#import <UIKit/UIKit.h>
#import "Users.h"
#import <CoreData/CoreData.h>
#import "DataModel.h"
#interface ProfileViewController : UIViewController
// CoreData Related
#property (strong, nonatomic) DataModel *Model;
// Instance Methods
- (void)updateProfileData;
// Core Data Method
- (void)getProfile;
#end
This method is called in the view controller's viewDidLoad method. When I run this, I get the following error:
'+entityForName: nil is not a legal NSManagedObjectContext parameter searching for entity name 'Users''
I have found a similar question here on StackOverflow that may help, but I still don't understand what the solution actually is.
'+entityForName: nil is not a legal NSManagedObjectContext parameter - Core Data
The stated solution from that thread was that he passed the context to the ViewController. How is this accomplished? I already thought I was doing that.
EDIT: DataModel.h:
#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>
#import "Workouts.h"
#import "sqlite3.h"
#interface DataModel : NSObject {
sqlite3 *Database;
}
#property (nonatomic, strong) Workouts *currentWorkout;
// Core Data Properties
#property (nonatomic, strong) NSManagedObjectContext *managedObjectContext;
#property (nonatomic, strong) NSManagedObjectModel *managedObjectModel;
#property (nonatomic, strong) NSPersistentStoreCoordinator *storeCoordinator;
+ (DataModel *)sharedInstance;
- (void)saveContext;
- (NSURL *)applicationDocumentsDirectory;
#end
DataModel.m:
#import "DataModel.h"
#implementation DataModel
#pragma mark - Core Data
+ (DataModel *)sharedInstance {
static DataModel *sharedModel = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sharedModel = [[DataModel alloc] init];
//sharedInstance.storeCoordinator = [sharedInstance storeCoordinator];
//sharedInstance.managedObjectContext = [sharedInstance managedObjectContext];
});
return sharedModel;
}
- (void)saveContext {
NSError *error = nil;
if (_managedObjectContext != nil) {
if ([_managedObjectContext hasChanges] && ![_managedObjectContext save:&error]) {
NSLog(#"error: %#", error.userInfo);
}
}
}
#pragma mark - Core Data Stack
- (NSManagedObjectContext *)managedObjectContext {
if (_managedObjectContext != nil) {
return _managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self storeCoordinator];
if (coordinator != nil) {
_managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
[_managedObjectContext setPersistentStoreCoordinator: coordinator];
}
return _managedObjectContext;
}
- (NSManagedObjectModel *)managedObjectModel {
if (_managedObjectModel != nil) {
return _managedObjectModel;
}
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:#"DataModel" withExtension:#"momd"];
_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return _managedObjectModel;
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
if (_storeCoordinator != nil) {
return _storeCoordinator;
}
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:#"model.sqlite"];
NSError *error = nil;
_storeCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:_managedObjectModel];
if (![_storeCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
}
return _storeCoordinator;
}
#pragma mark Application's Documents Directory
- (NSURL *)applicationDocumentsDirectory {
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}
#end
UPDATE: I realize the reason why the objects were (null). I was trying to call the sharedInstance singleton method and they were not calling correctly. The getter was being called and would throw into a loop that would keep calling the getter. I correctly used the synthesized variables _managedObjectContext and _storeCoordinator. The objects now appropriately allocate memory and return the reference. Thanks for the help everyone.

There isn't anything wrong with the Core Data Stack being created in the Application Delegate. Where have you read that this is the case.
It's certainly considered bad design to be calling down to the Application Delegate to get the managed object context, but what most people do is to pass a reference to the managed object context from the Application Delegate to the other view controllers that use it.

Dumb question: Your model is in fact named DataModel?

Related

What is the best way to fetch data in core data between two regular view controllers?

Sorry if the title is bad. What I'm trying to understand is: in the core data examples I have found online they explain how to use core data with nsfetchresultcontroller. But from what I understand nsfetchresultcontroller is made for table views. But I have only 2 regular view controllers.
It's really basic, I have 1 view controller for a create page to create a task, and another one which is the homepage with a label to show that single task that was created:
HomePageViewController.m:
#import "HomePageViewController.h"
#import "CreatTargetViewController.h"
#interface HomePageViewController ()
#property (weak, nonatomic) IBOutlet UILabel *currentTarget;
#end
#implementation HomePageViewController
- (IBAction)unwindToHomePage:(UIStoryboardSegue *)segue
{
CreatTargetViewController *source = (CreatTargetViewController *)[segue sourceViewController];
self.currentTarget.text = source.target.content;
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
CreatTargetViewController.h:
#import <UIKit/UIKit.h>
#import "Targets.h"
#interface CreatTargetViewController : UIViewController
#property (nonatomic, strong) Targets *target;
#end
CreatTargetViewController.m:
#import "CreatTargetViewController.h"
#import "Targets.h"
#import "CoreDataStack.h"
#interface CreatTargetViewController ()
#property (weak, nonatomic) IBOutlet UIBarButtonItem *saveButton;
#property (weak, nonatomic) IBOutlet UITextView *myTextView;
#end
#implementation CreatTargetViewController
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if (sender != self.saveButton) return;
if (self.target != nil) {
self.myTextView.text = self.target.content;
}
}
- (void)insertNewTargetEntry
{
CoreDataStack *coreDataStack = [CoreDataStack defaultStack];
Targets *entry = [NSEntityDescription insertNewObjectForEntityForName:#"Targets" inManagedObjectContext:coreDataStack.managedObjectContext];
entry.content = self.myTextView.text;
[coreDataStack saveContext];
}
- (void)updateTargetEntry
{
self.target.content = self.myTextView.text;
CoreDataStack *stack = [CoreDataStack defaultStack];
[stack saveContext];
}
- (IBAction)saveWasPressed:(id)sender
{
if (self.target != nil) {
[self updateTargetEntry];
} else {
[self insertNewTargetEntry];
}
}
- (void)viewWillAppear:(BOOL)animated
{
[self.myTextView becomeFirstResponder];
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
and another class for the core data stack:
#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>
#interface CoreDataStack : NSObject
#property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
#property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
#property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;
+ (instancetype)defaultStack;
- (void)saveContext;
- (NSURL *)applicationDocumentsDirectory;
#end
CoreDataStack.m:
#import "CoreDataStack.h"
#implementation CoreDataStack
#pragma mark - Core Data stack
#synthesize managedObjectContext = _managedObjectContext;
#synthesize managedObjectModel = _managedObjectModel;
#synthesize persistentStoreCoordinator = _persistentStoreCoordinator;
+ (instancetype)defaultStack
{
static CoreDataStack *defaultStack;
static dispatch_once_t onceToken;
dispatch_once (&onceToken, ^{
defaultStack = [[self alloc] init];
});
return defaultStack;
}
- (NSURL *)applicationDocumentsDirectory {
// The directory the application uses to store the Core Data store file. This code uses a directory named "digitalCrown.LaserApp" in the application's documents directory.
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}
- (NSManagedObjectModel *)managedObjectModel {
// The managed object model for the application. It is a fatal error for the application not to be able to find and load its model.
if (_managedObjectModel != nil) {
return _managedObjectModel;
}
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:#"LaserApp" withExtension:#"momd"];
_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return _managedObjectModel;
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
// The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it.
if (_persistentStoreCoordinator != nil) {
return _persistentStoreCoordinator;
}
// Create the coordinator and store
_persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:#"LaserApp.sqlite"];
NSError *error = nil;
NSString *failureReason = #"There was an error creating or loading the application's saved data.";
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
// Report any error we got.
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
dict[NSLocalizedDescriptionKey] = #"Failed to initialize the application's saved data";
dict[NSLocalizedFailureReasonErrorKey] = failureReason;
dict[NSUnderlyingErrorKey] = error;
error = [NSError errorWithDomain:#"YOUR_ERROR_DOMAIN" code:9999 userInfo:dict];
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
return _persistentStoreCoordinator;
}
- (NSManagedObjectContext *)managedObjectContext {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.)
if (_managedObjectContext != nil) {
return _managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (!coordinator) {
return nil;
}
_managedObjectContext = [[NSManagedObjectContext alloc] init];
[_managedObjectContext setPersistentStoreCoordinator:coordinator];
return _managedObjectContext;
}
#pragma mark - Core Data Saving support
- (void)saveContext {
NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
if (managedObjectContext != nil) {
NSError *error = nil;
if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
}
}
How do I communicate the data here?

Enabling Core data into existing Project does not work

I have created a Project in Xcode 5.1.1 without core data support.
Now i am trying to get the core data support.
Steps:
1) File -> New -> File -> Data Model -> Added.
It created : samplecd.xcdatamodeld
2) Added Entity:
myname type: String
3)
To do the changes in the AppDelegate.h and AppDelegate.m,
I have created one more project with 'core data' enabled, and copied
the below contents into the previous project.
AppDelegate.h
#property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
#property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
#property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;
- (void)saveContext;
- (NSURL *)applicationDocumentsDirectory;
AppDelegate.m
- (void)saveContext
{
NSError *error = nil;
NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
if (managedObjectContext != nil) {
if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
}
}
#pragma mark - Core Data stack
// Returns the managed object context for the application.
// If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
- (NSManagedObjectContext *)managedObjectContext
{
if (_managedObjectContext != nil) {
return _managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
_managedObjectContext = [[NSManagedObjectContext alloc] init];
[_managedObjectContext setPersistentStoreCoordinator:coordinator];
}
return _managedObjectContext;
}
- (NSManagedObjectModel *)managedObjectModel
{
if (_managedObjectModel != nil) {
return _managedObjectModel;
}
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:#"withcoredata" withExtension:#"momd"];
_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return _managedObjectModel;
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
if (_persistentStoreCoordinator != nil) {
return _persistentStoreCoordinator;
}
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:#"withcoredata.sqlite"];
NSError *error = nil;
_persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
return _persistentStoreCoordinator;
}
#pragma mark - Application's Documents directory
// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory
{
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}
ERROR:
I get the below compilation error:
"AppDelegate.m:122:35: Receiver 'NSManagedObjectContext' for class message is a forward declaration"
AppDelegate.m:122:34: Receiver type 'NSManagedObjectContext' for instance message is a forward declaration
How to solve this issue?
your core data model name is samplecd and your sqlite database name is withcoredata
both name should be similar for using core data in existing project.
Change the name and let me know if your problem is solved or not.
You need to import CoreData/CoreData.h in your AppDelegte.h file:
#import <CoreData/CoreData.h>
and in YourApp-Prefix.pch:
#ifdef __OBJC__
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>
#endif

Why won't my model save to Core Data?

I'm quite new to Objective-C and I'm trying to mess around with Core Data. I have the following App Delegate interface and implementation:
#import <UIKit/UIKit.h>
#interface SDTAppDelegate : UIResponder <UIApplicationDelegate>
#property (strong, nonatomic) UIWindow *window;
#property (nonatomic, strong) NSManagedObjectContext *managedObjectContext;
#property (nonatomic, strong) NSManagedObjectModel *managedObjectModel;
#property (nonatomic, strong) NSPersistentStoreCoordinator *persistentStoreCoordinator;
- (void)saveManagedObjectContext;
- (NSManagedObjectContext *)setupManagedObjectContext;
- (NSManagedObjectModel *)setupManagedObjectModel;
- (NSPersistentStoreCoordinator *)setupPersistentStoreCoordinator;
- (NSURL *)applicationDocumentsDirectory;
#end
Implementation
#import "SDTAppDelegate.h"
#import "ToDoItem.h"
#implementation SDTAppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Get the managed object context and associate it to the app delegate
self.managedObjectContext = [self setupManagedObjectContext];
return YES;
}
- (void)applicationWillTerminate:(UIApplication *)application
{
[self saveManagedObjectContext];
}
/**
* Save the MOC!
*/
- (void)saveManagedObjectContext
{
NSError *error = nil;
if (self.managedObjectContext != nil)
{
if ([self.managedObjectContext hasChanges] && ![self.managedObjectContext save:&error])
{
/*
THIS NEEDS TO BE REPLACED
*/
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
}
}
#pragma mark - Core Data stack
/**
Returns the managed object context for the application.
If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
*/
- (NSManagedObjectContext *)setupManagedObjectContext
{
if (self.managedObjectContext != nil)
{
return self.managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self setupPersistentStoreCoordinator];
if (coordinator != nil)
{
self.managedObjectContext = [[NSManagedObjectContext alloc] init];
[self.managedObjectContext setPersistentStoreCoordinator:coordinator];
}
return self.managedObjectContext;
}
/**
* Return the managed object model. If it doesn't exist, create it.
*/
- (NSManagedObjectModel *)setupManagedObjectModel
{
if (self.managedObjectModel != nil)
{
return self.managedObjectModel;
}
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:#"Model" withExtension:#"momd"];
self.managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return self.managedObjectModel;
}
/**
* Return the persistent store coordinator. If it doesn't exist, create it.
*/
- (NSPersistentStoreCoordinator *)setupPersistentStoreCoordinator
{
if (self.persistentStoreCoordinator != nil)
{
return self.persistentStoreCoordinator;
}
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:#"Model.sqlite"];
NSError *error = nil;
self.persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self setupManagedObjectModel]];
if (![self.persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType
configuration:nil
URL:storeURL
options:nil
error:&error])
{
/*
THIS NEEDS TO BE REPLACED
*/
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
return self.persistentStoreCoordinator;
}
#pragma mark - Application's Documents directory
/**
* Return the URL to the application's Documents directory.
*/
- (NSURL *)applicationDocumentsDirectory
{
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}
#end
And then in my controller I have the following to save a new model:
// Take the managed object context from the app delegate
SDTAppDelegate *appDelegate = (SDTAppDelegate *)[UIApplication sharedApplication].delegate;
NSManagedObjectContext *context = appDelegate.managedObjectContext;
// Add the new item
ToDoItem *newItem = [NSEntityDescription insertNewObjectForEntityForName:#"ToDoItem" inManagedObjectContext:context];
newItem.item = self.textField.text;
newItem.completed = 0;
No matter what happens I can't get the application to save. It shows up fine in the interface, but when I quit and restart the data is no longer there. I'm guessing this is something wrong with my persistent storage?
You should save the context in order to save in the persistent store.
NSError *error;
[context save:&error];
Hope it helps. Cheers

Syncing core data with iCloud - excluding entities

Im adding to iCloud to an existing app. Syncing works fine however I need to exclude some entities, or come up with a work around as some of my core data is being duplicated.
eg:
CertificateColour is sent to a table view and each row is shown twice now.
CertificateType presents four options in a action sheet, now 8 rows are present, with each row having been duplicated once.
Im using https://github.com/mluisbrown/iCloudCoreDataStack for my core data sync.
I checked out Core data + iCloud: exclude certain attributes from sync? That suggested a couple things:
1. Creating a separate local and cloud store, sounds...promising but not sure how as this is my first attempt with iCloud and Core data.
2. The second suggestion was sync to an entity that includes a unique device identifier but this is deprecated and again unsure of the process with core data
AppDelegate.h
#import <UIKit/UIKit.h>
#import <sqlite3.h>
#import "PersistentStack.h"
#interface ICAppDelegate : UIResponder <UIApplicationDelegate>
#property (strong, nonatomic) UIWindow *window;
#property (strong, nonatomic) UINavigationController *navigationController;
#property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
#property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
#property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;
- (void)saveContext;
- (NSURL *)applicationDocumentsDirectory;
#end
Appdelegate.m
#interface ICAppDelegate () <DBSessionDelegate, DBNetworkRequestDelegate>
//iCloud
#property (nonatomic, strong) PersistentStack* persistentStack;
#property (nonatomic, strong) NSManagedObjectContext* managedObjectContext;
#end
#implementation ICAppDelegate
#synthesize window = _window;
#synthesize navigationController = _navigationController;
#synthesize managedObjectContext = __managedObjectContext;
#synthesize managedObjectModel = __managedObjectModel;
#synthesize persistentStoreCoordinator = __persistentStoreCoordinator;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
//iCloud
self.persistentStack = [[PersistentStack alloc] initWithStoreURL:self.storeURL modelURL:self.modelURL];
self.managedObjectContext = self.persistentStack.managedObjectContext;
BOOL populateData = NO;
BOOL copyDb = YES;
// Copy DB to documents directory
if (copyDb == YES) {
NSString *srcPath = [[NSBundle mainBundle] pathForResource:#"myApp" ofType:#"sqlite"];
NSString *destPath = [[NSHomeDirectory() stringByAppendingPathComponent:#"Documents"] stringByAppendingPathComponent:#"myApp.sqlite"];
if (![[NSFileManager defaultManager] fileExistsAtPath:srcPath]) {
DebugLog(#"Source file doesn't exist");
}
if (![[NSFileManager defaultManager] fileExistsAtPath:destPath]) {
DebugLog(#"Copying DB to documents directory");
NSError *error = nil;
[[NSFileManager defaultManager] copyItemAtPath:srcPath toPath:destPath error:&error];
if (error != nil) {
DebugLog(#"Copy failed %#", [error localizedDescription]);
}
}
}
/////*****ALL OF THIS IS DUPLICATED AND NEEDS EXCLUDING FROM ICLOUD BACK UP****////////////
if (populateData) {
DebugLog(#"Populating database");
NSManagedObjectContext *context = [self managedObjectContext];
Subscription *subscription = (Subscription *)[NSEntityDescription insertNewObjectForEntityForName:#"Subscription" inManagedObjectContext:context];
subscription.subscribed = #NO;
CertificateColour *red = (CertificateColour *)[NSEntityDescription insertNewObjectForEntityForName:#"CertificateColour" inManagedObjectContext:context];
red.name = #"Red";
red.redComponent = #1.0f;
red.greenComponent = #0.0f;
red.blueComponent = #0.0f;
CertificateColour *purple = (CertificateColour *)[NSEntityDescription insertNewObjectForEntityForName:#"CertificateColour" inManagedObjectContext:context];
purple.name = #"Purple";
purple.redComponent = #0.4f;
purple.greenComponent = #0.0f;
purple.blueComponent = #0.6f;
CertificateColour *green = (CertificateColour *)[NSEntityDescription insertNewObjectForEntityForName:#"CertificateColour" inManagedObjectContext:context];
green.name = #"Green";
green.redComponent = #0.0f;
green.greenComponent = #0.6f;
green.blueComponent = #0.2f;
CertificateColour *blue = (CertificateColour *)[NSEntityDescription insertNewObjectForEntityForName:#"CertificateColour" inManagedObjectContext:context];
blue.name = #"Blue";
blue.redComponent = #0.0f;
blue.greenComponent = #0.2f;
blue.blueComponent = #1.0f;
ICCertificateTypeManager *ctm = [ICCertificateTypeManager manager];
CertificateType *type = [ctm newCertificateType];
type.title = #"Works";
type.identifier = #(Works);
type = [ctm newCertificateType];
type.title = #"Type1";
type.identifier = #(Type1);
type = [ctm newCertificateType];
type.title = #"Type2";
type.identifier = #(Type2);
type = [ctm newCertificateType];
type.title = #"Type4";
type.identifier = #(Type3);
[self saveContext];
}
if ([[ICWebServiceClient sharedInstance] isLoggedIn])
{
DebugLog(#"User is logged in ");
}
////////////////////////////////////////////////////////////
return YES;
}
- (BOOL)application:(UIApplication *)application handleOpenURL:(NSURL *)url {
LogCmd();
if ([[DBSession sharedSession] handleOpenURL:url]) {
if ([[DBSession sharedSession] isLinked]) {
DebugLog(#"handling url");
}
return YES;
}
return NO;
}
- (void)applicationWillResignActive:(UIApplication *)application
{
}
- (void)applicationDidEnterBackground:(UIApplication *)application
{
[self.managedObjectContext save:NULL];
}
- (void)applicationWillEnterForeground:(UIApplication *)application
{
}
- (void)applicationDidBecomeActive:(UIApplication *)application
{
}
- (void)applicationWillTerminate:(UIApplication *)application
{
[self saveContext];
}
- (void)saveContext
{
NSError *error = nil;
NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
if (managedObjectContext != nil) {
if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
}
}
#pragma mark - DBSessionDelegate
- (void)sessionDidReceiveAuthorizationFailure:(DBSession*)session userId:(NSString *)userId
{
LogCmd();
}
#pragma mark - DBNetworkRequestDelegate
static int outstandingRequests;
- (void)networkRequestStarted {
outstandingRequests++;
if (outstandingRequests == 1) {
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
}
}
- (void)networkRequestStopped {
outstandingRequests--;
if (outstandingRequests == 0) {
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
}
}
#pragma mark - Core Data stack
// Returns the managed object context for the application.
// If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
- (NSManagedObjectContext *)managedObjectContext
{
if (__managedObjectContext != nil) {
return __managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
__managedObjectContext = [[NSManagedObjectContext alloc] init];
[__managedObjectContext setPersistentStoreCoordinator:coordinator];
}
return __managedObjectContext;
}
// Returns the managed object model for the application.
// If the model doesn't already exist, it is created from the application's model.
- (NSManagedObjectModel *)managedObjectModel
{
if (__managedObjectModel != nil) {
return __managedObjectModel;
}
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:#"myApp" withExtension:#"momd"];
__managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return __managedObjectModel;
}
// Returns the persistent store coordinator for the application.
// If the coordinator doesn't already exist, it is created and the application's store added to it.
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
if (__persistentStoreCoordinator != nil) {
return __persistentStoreCoordinator;
}
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:#"myApp.sqlite"];
NSError *error = nil;
__persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
return __persistentStoreCoordinator;
}
#pragma mark - Application's Documents directory
// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory
{
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}
#pragma mark - iCloud store
- (NSURL*)storeURL
{
NSURL* documentsDirectory = [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:YES error:NULL];
return [documentsDirectory URLByAppendingPathComponent:#"myApp.sqlite"];
}
- (NSURL*)modelURL
{
return [[NSBundle mainBundle] URLForResource:#"myApp" withExtension:#"momd"];
}
#end
Using multiple persistent stores is really the only option for excluding specific entity types from iCloud. You do that by calling addPersistentStoreWithType more than once on the same persistent store coordinator but with different persistent store files (it's called a coordinator because it can coordinate between multiple persistent stores). Use iCloud options for one of the stores but not for the other.
You can either use two separate managed object models with different entities, or you can use a single model with different configuration options. Either is effective.
The problem you'll probably have with this is that you can't create relationships between instances in different persistent store files. (Technically you can create them, you just can't save them, which in most cases makes them useless). Your CertificateType entity sounds like it would have relationships to other instances, but that's not going to work with multiple stores.
What you can do instead is sync every object but add code to detect the duplicates and deal with them. There was a good example of this in Apple's "SharedCoreData" sample app from the "Using iCloud with Core Data" session at WWDC 2012, but I can't find a copy of that online right now. You'd do something like
Wait on NSPersistentStoreDidImportUbiquitousContentChangesNotification
When it arrives, look at the notification's userInfo to see if any of your CertificateType objects are included.
If so, do a fetch for that entity to find and match up duplicates
Clean up those duplicates in whatever way makes sense for your app.
Update: I forgot that I had done a blog post which covers this in more detail. I also found a link to the WWDC 2012 sample code bundle (link requires current developer account) which includes SharedCoreData. A lot of what's in that demo is obsolete, but the duplicate removal code is as valid as ever.

Multiple xcdatamodel files in Xcode

My project(for managing students' attendance in various classes) contains 2 xkcddatamodel files, one for the semester start/end dates and the other for the course data. If you look at AppDelegate.m, I've set the modelURL to the second model. How am I supposed to create a second context for the first xkcddatamodel? I've tried the solution given here. But no dice. Xcode isn't even recognising it and is asking me to replace managedObjectContext2 with managedObjectContext. How do I fix this?
Dropbox link to the project: https://www.dropbox.com/sh/ivl6nw6nw8p9j1y/MDwYDaHVH_
Here's the AppDelegate.m
//
// AppDelegate.m
// timetable app
//
// Created by Robin Malhotra on 22/12/13.
// Copyright (c) 2013 Robin's code kitchen. All rights reserved.
//
#import "AppDelegate.h"
#import <CoreData/CoreData.h>
#implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Override point for customization after application launch.
return YES;
}
// Explicitly write Core Data accessors
- (NSManagedObjectContext *) managedObjectContext {
if (managedObjectContext != nil) {
return managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
managedObjectContext = [[NSManagedObjectContext alloc] init];
[managedObjectContext setPersistentStoreCoordinator: coordinator];
}
return managedObjectContext;
}
- (NSManagedObjectModel *)managedObjectModel {
if (managedObjectModel != nil) {
return managedObjectModel;
}
// removed some code about retain here as ARC hates that
return managedObjectModel;
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
if (persistentStoreCoordinator != nil) {
return persistentStoreCoordinator;
}
NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory]
stringByAppendingPathComponent: #"Courses.sqlite"]];
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:#"ClassesAttended" withExtension:#"momd"];
managedObjectModel=[[NSManagedObjectModel alloc]initWithContentsOfURL:modelURL];
NSError *error = nil;
persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc]
initWithManagedObjectModel:[self managedObjectModel]];
if(![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType
configuration:nil URL:storeUrl options:nil error:&error]) {
/*Error for store creation should be handled in here*/
}
return persistentStoreCoordinator;
}
- (NSString *)applicationDocumentsDirectory {
return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
}
/* (...Existing Application Code...) */
-(NSArray *)getAllCourses
{
NSFetchRequest *request=[[NSFetchRequest alloc]init];
NSEntityDescription *entitydesc=[NSEntityDescription entityForName:#"Course" inManagedObjectContext:managedObjectContext];
[request setEntity:entitydesc];
NSError *error;
NSArray *fetchedCourses=[self.managedObjectContext executeFetchRequest:request error:&error];
return fetchedCourses;
}
#end
and here's the AppDelegate.h
#import <UIKit/UIKit.h>
#interface AppDelegate : UIResponder <UIApplicationDelegate>
{
NSManagedObjectModel *managedObjectModel;
NSManagedObjectContext *managedObjectContext;
NSPersistentStoreCoordinator *persistentStoreCoordinator;
}
#property (strong, nonatomic) UIWindow *window;
#property (nonatomic, readonly) NSManagedObjectModel *managedObjectModel;
#property (nonatomic, readonly) NSManagedObjectContext *managedObjectContext;
#property (nonatomic, readonly) NSPersistentStoreCoordinator *persistentStoreCoordinator;
#property (nonatomic, readonly) NSManagedObjectModel *managedObjectModel2;
#property (nonatomic, readonly) NSManagedObjectContext *managedObjectContext2;
#property (nonatomic, readonly) NSPersistentStoreCoordinator *persistentStoreCoordinator2;
- (NSString *)applicationDocumentsDirectory;
- (NSArray *)getAllCourses;
#end

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