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POHandle CoreData not in RootViewController(migration of vanilla coredata-project)
 

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  1. POHandle CoreData not in RootViewController(migration of vanilla coredata-project)
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    <p>First, I'm really new to CoreData.</p> <p>Now I've created a vanilla CoreData-project and have copied all the code to my project in which I want to implement CoreData.</p> <p>In the CoreData-vanilla project, the first viewcontroller(MasterViewController), is the controller who handles the managedObjectContext:</p> <pre><code>- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after application launch. UINavigationController *navigationController = (UINavigationController *)self.window.rootViewController; BilderViewController *controller = (BilderViewController *)navigationController.topViewController; controller.managedObjectContext = self.managedObjectContext; return YES; } </code></pre> <p>But I want my second ViewController, to handle CoreData:</p> <p><img src="https://i.stack.imgur.com/G0gUO.png" alt="enter image description here"></p> <p>As you see here, I want the "Bilder"-Viewcontroller to handle/use Core Data. Every method is in that controller, so it should work. I've already tried to change the method to:</p> <pre><code>- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after application launch. BilderViewController *controller = [[BilderViewController alloc] init]; controller.managedObjectContext = self.managedObjectContext; return YES; } </code></pre> <p>But than, I receive the error:</p> <blockquote> <p>Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+entityForName: nil is not a legal NSManagedObjectContext parameter searching for entity name 'Event''</p> </blockquote> <p>My managedObjectContext-method:</p> <pre><code>// 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; } </code></pre> <p>How can I fix this?</p> <p>Btw: Eventually, somebody also knows, why the prototype-cell isn't at the top of my tableview. Thx.</p>
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    1. USChristian
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    1. COI suspect you're just passing nil around for the managed object context. Does your app delegate initialize the Core Data stack? That's how the context gets a value.
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      1. POHandle CoreData not in RootViewController(migration of vanilla coredata-project)
      1. USbilobatum
    2. COI've edited my question and added the managedObjectContext method
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      1. POHandle CoreData not in RootViewController(migration of vanilla coredata-project)
      1. USChristian
 

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