Unable to pass NSManagedObjectContext to my view controller - ios

Question

Ok, I may be in well over my head here, but suspect I am missing something quite fundamental. I have searched on stack and other forums for help on finding a solution. I've tried all the solutions I have found but none work for my situation and I cannot see what I am missing.
I have created a CoreData app. All works fine in reading and writing data to the CoreData store using NSManagedObjectContext within my appDelegate. I have checked to see if the NSManagedObjectContext is set in my AppDelegate and it is. After passing it to my only viewController I check to see if it is set and it isn't. So that is clearly my issue. I have tried everything and cannot fathom the solution, now tired and want to go to bed. I'm pretty new to iOS, so I am sure it's something fundamental.
Here's my code as it stands.
AppDelegate.m
#import "AppDelegate.h"
#import "ViewController.h"
#import "Recipe.h"
#interface AppDelegate()
#property (nonatomic, strong) NSManagedObjectContext *managedObjectContext;
#property (nonatomic, strong) NSManagedObjectModel *managedObjectModel;
#property (nonatomic, strong) NSPersistentStoreCoordinator *persistentStoreCoordinator;
#property (nonatomic, strong) ViewController *viewController;
#end
#implementation AppDelegate
#synthesize managedObjectModel, managedObjectContext, persistentStoreCoordinator, viewController;
#synthesize window = _window;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSManagedObjectContext *context = [self managedObjectContext];
if (!context) {
NSLog(#"There is an error!!!");
}
if (context == nil) {
NSLog(#"Context is nil in appdelegate");
}
else {
NSLog(#"Context is set in appdelegate");
}
viewController.managedObjectContext = self.managedObjectContext;
// Override point for customization after application launch.
return YES;
}
#pragma mark - Core Data
- (NSManagedObjectModel *)managedObjectModel
{
if (managedObjectModel == nil) {
NSString *modelPath = [[NSBundle mainBundle] pathForResource:#"RecipeBook" ofType:#"momd"];
NSURL *modelURL = [NSURL fileURLWithPath:modelPath];
managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
}
return managedObjectModel;
}
- (NSString *)documentsDirectory
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
return documentsDirectory;
}
- (NSString *)dataStorePath
{
return [[self documentsDirectory] stringByAppendingPathComponent:#"DataStore.sqlite"];
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
if (persistentStoreCoordinator == nil) {
NSURL *storeURL = [NSURL fileURLWithPath:[self dataStorePath]];
persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:self.managedObjectModel];
NSError *error;
if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
NSLog(#"Error adding persistent store %#, %#", error, [error userInfo]);
abort();
}
}
return persistentStoreCoordinator;
}
- (NSManagedObjectContext *)managedObjectContext
{
if (managedObjectContext == nil) {
NSPersistentStoreCoordinator *coordinator = self.persistentStoreCoordinator;
if (coordinator != nil) {
managedObjectContext = [[NSManagedObjectContext alloc] init];
[managedObjectContext setPersistentStoreCoordinator:coordinator];
}
}
return managedObjectContext;
}
#end
ViewController.h
#import <UIKit/UIKit.h>
#interface ViewController : UITableViewController {
NSArray *recipes;
NSManagedObjectContext *managedObjectContext;
}
#property (nonatomic, retain) NSArray *recipes;
#property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;
#end
ViewController.m
#import "ViewController.h"
#import "Recipe.h"
#interface ViewController ()
#end
#implementation ViewController
#synthesize recipes;
#synthesize managedObjectContext;
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(#"View Did Load");
NSManagedObjectContext *context = [self managedObjectContext];
if (!context) {
NSLog(#"There is an error!!!");
}
if (context == nil) {
NSLog(#"Context is nil in viewController");
}
else {
NSLog(#"Context is set in viewController");
}
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
} else {
return YES;
}
}
- (void)viewDidUnload {
[super viewDidUnload];
}
#end
I know the NSManagedObjectContext is nil in my ViewController. The question is how do I pass my context from AppDelegate into ViewController? I don't want to have to question the AppDelegate from my viewControllers (More will hopefully be added) every time I want to query CoreData, I'm looking to pass the managedObjectContext around.
I hope that all makes sense. :)

Answer 1

I have discovered the answer to my issue. The managedObjectContext wasn't being passed correctly to my viewController.
I was using:
viewController.managedObjectContext = self.managedObjectContext;
When I should have been using:
ViewController *viewController = (ViewController *)self.window.rootViewController;
viewController.managedObjectContext = self.managedObjectContext;
Thanks user523234 for putting me on the right lines.