我第一次接触Core Data时,在设备上运行代码时遇到以下错误,但在模拟器上工作正常。
我的一些可能导致此问题的方法:
- (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:@"RugbyOnTv" 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;
}
NSString *storePath = [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"RugbyOnTV.sqlite"];
NSURL *storeUrl = [NSURL fileURLWithPath:storePath];
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];
__persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];
NSError *error = nil;
__persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:options error:&error]) {
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
return __persistentStoreCoordinator;
}
- (NSString *)applicationDocumentsDirectory {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *basePath = ([paths count] > 0) ? [paths objectAtIndex:0] : nil;
return basePath;
}
编辑
我从Apple的CoreDataBooks复制并粘贴了ManagedObjectContext方法(如下),现在可以使用了。
- (NSManagedObjectModel *)managedObjectModel {
if (managedObjectModel != nil) {
return managedObjectModel;
}
managedObjectModel = [[NSManagedObjectModel mergedModelFromBundles:nil] retain];
return managedObjectModel;
}
最佳答案
我有与原始帖子完全相同的错误消息。我为此花了好几个小时。
这是我的AppDelegate.m中的这一行。
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"[same with name of xcdatamodeld]" withExtension:@"momd"];
对于在那里搜索此错误消息并找到该线程的任何人。
您必须确保它说的是[与xcdatamodeld的名称相同]...。
由于某种原因,我的项目名称在那里,而不是数据模型名称。
更改它,它立即起作用.....
感谢Rock&Muller的贡献....您救了我几天!!
加兹
关于objective-c - 无法使用nil模型创建NSPersistentStoreCoordinator,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/7361187/