错误在iPhone核心数据

Question

我AppDelegate.h：

#import <UIKit/UIKit.h> 
#import "Child.h" 

@interface AppDelegate : UIResponder <UIApplicationDelegate> { 
    NSManagedObjectModel *managedObjectModel; 
    NSManagedObjectContext *managedObjectContext; 
    NSPersistentStoreCoordinator *persistentStoreCoordinator; 
} 
@property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext; 
@property (readonly, retain, nonatomic) NSManagedObjectModel *managedObjectModel; 
@property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator; 
- (NSString *)applicationDocumentsDirectory; 
@property (strong, nonatomic) UIWindow *window; 
@end 

AppDelegate.m：

#import "AppDelegate.h" 
@implementation AppDelegate 

@synthesize managedObjectContext = __managedObjectContext; 
@synthesize managedObjectModel = __managedObjectModel; 
@synthesize persistentStoreCoordinator = __persistentStoreCoordinator; 
@synthesize window = _window; 

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 
    // Override point for customization after application launch. 
    NSManagedObjectContext *context = [self managedObjectContext]; 
    if (!context) { 
     NSLog(@"Error"); 
    } 
    return YES; 
} 
- (void)applicationWillTerminate:(UIApplication *)application { /* Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:. */ 
    NSError *error; 
    if (managedObjectContext != nil) { 
     if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) { 
     // Handle the error. 
     } 
    } 
} 
// 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; 
    } 
    managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil]; 
    return managedObjectModel; 
} 
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator { 
    if (persistentStoreCoordinator != nil) { 
     return persistentStoreCoordinator; 
    } 
    NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"iSalahProject.sqlite"]]; 
    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 { 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *basePath = ([paths count] > 0) ? [paths objectAtIndex:0] : nil; 
    return basePath; 
} 
@end 

我的控制器实现类在正在创建的实体，我得到的错误：

-(IBAction)addChildren:(id)sender{ 
    inputChildName = nameOfChild.text; 
    NSManagedObjectContext *context = [app managedObjectContext]; 
    Child * childrenName = [NSEntityDescription insertNewObjectForEntityForName:@"Child" inManagedObjectContext:context]; 
    childrenName.name = inputChildName; 
} 

我得到的错误是：

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '+entityForName: could not locate an NSManagedObjectModel for entity name 'Child'' 

我正在使用iOS-5 XCode 4.2 ARC。请帮我解决这个问题，我已经花了数小时解决它，但我找不到任何解决方案。

Answer 1

您的申请正在终止，因为您的managedObjectContext为零。检查它，如果它的零从委托复制它。您可以在-(IBAction)addChildren:(id)sender方法使用，如果条件

if (managedObjectContext == nil) 
{ 
    managedObjectContext = [(CoreDataBooksAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext]; 
    NSLog(@"After managedObjectContext: %@", managedObjectContext); 
} 

Answer 2

以下是该错误发生的可能性：

• 错别字的实体名称。
• 无管理的对象上下文对象。
• 无法将包含实体的模型添加到上下文使用的持久存储 。
• 未能将正确的持久存储添加到上下文本身。