我正在使用一个未记录的 API (Osirix),我对我在这里发布的那个有一个姐妹问题。
我在从托管对象上下文加载对象时遇到问题。
从 API 加载,使用它们的 _context 和 _model 实例
2010-05-28 14:05:13.588 OsiriX[44012:a0f] Entity: Study
2010-05-28 14:05:13.589 OsiriX[44012:a0f] EntityClassName: DicomStudy
2010-05-28 14:05:13.589 OsiriX[44012:a0f] ClassName: DicomStudy
从 Fetch Request 加载(以及我自己的 _context 和 _model 实例)
2010-05-28 14:19:09.956 rcOsirix[44431:7a03] Entity: Study
2010-05-28 14:19:09.957 rcOsirix[44431:7a03] EntityClassName: DicomStudy
2010-05-28 14:19:09.958 rcOsirix[44431:7a03] ClassName: NSManagedObject
输出由:
NSLog(@"Entity: %@",[[item entity] name]);
NSLog(@"EntityClassName: %@", [[item entity] managedObjectClassName]);
NSLog(@"ClassName: %s", class_getName(object_getClass([item class])));
所以很明显,即使实体认为它是一个 DicomSeries - 它不是。它只是一个 NSManagedObject。DicomSeries 有一些“硬编码”的 KVC 内容,我在另一个问题中遇到了问题。
我在这个线程中追求不同的推理方式——加载对象。
以下是他们的代码:
- (NSManagedObjectModel *)managedObjectModel
{
if (managedObjectModel) return managedObjectModel;
NSMutableSet *allBundles = [[NSMutableSet alloc] init];
[allBundles addObject: [NSBundle mainBundle]];
[allBundles addObjectsFromArray: [NSBundle allFrameworks]];
managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL: [NSURL fileURLWithPath: [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"/OsiriXDB_DataModel.mom"]]];
[allBundles release];
return managedObjectModel;
}
- (NSManagedObjectContext *) managedObjectContextLoadIfNecessary:(BOOL) loadIfNecessary
{
NSError *error = nil;
NSString *localizedDescription;
NSFileManager *fileManager;
if( currentDatabasePath == nil)
return nil;
if (managedObjectContext)
return managedObjectContext;
if( loadIfNecessary == NO) return nil;
fileManager = [NSFileManager defaultManager];
[persistentStoreCoordinator release];
persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: self.managedObjectModel];
managedObjectContext = [[NSManagedObjectContext alloc] init];
[managedObjectContext setPersistentStoreCoordinator: persistentStoreCoordinator];
NSURL *url = [NSURL fileURLWithPath: currentDatabasePath];
if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:url options:nil error:&error])
{
NSLog(@"********** managedObjectContextLoadIfNecessary FAILED: %@", error);
localizedDescription = [error localizedDescription];
error = [NSError errorWithDomain:@"OsiriXDomain" code:0 userInfo:[NSDictionary dictionaryWithObjectsAndKeys:error, NSUnderlyingErrorKey, [NSString stringWithFormat:@"Store Configuration Failure: %@", ((localizedDescription != nil) ? localizedDescription : @"Unknown Error")], NSLocalizedDescriptionKey, nil]];
}
[[managedObjectContext undoManager] setLevelsOfUndo: 1];
[[managedObjectContext undoManager] disableUndoRegistration];
// This line is very important, if there is NO database.sql file
[self saveDatabase: currentDatabasePath];
return managedObjectContext;
}
这是我的代码:
NSManagedObjectModel* DataModule::managedObjectModel()
{
if (_managedObjectModel) return _managedObjectModel;
NSMutableSet *allBundles = [[NSMutableSet alloc] init];
[allBundles addObject: [NSBundle mainBundle]];
[allBundles addObjectsFromArray: [NSBundle allFrameworks]];
_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL: [NSURL fileURLWithPath: [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"/OsiriXDB_DataModel.mom"]]];
[allBundles release];
return [_managedObjectModel retain];
}
...
NSError *error = nil;
[_storeCoordinator release];
_storeCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: managedObjectModel()];
_context = [[NSManagedObjectContext alloc] init];
[_context setPersistentStoreCoordinator: _storeCoordinator];
NSURL *url = [NSURL fileURLWithPath: [[NSString alloc] initWithCString:_DBPath.c_str()]];
if (url == nil) { [pool release]; _loadLock = false; return nil; }
if (![_storeCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:url options:nil error:&error])
{
NSLog(@"********** managedObjectContextLoadIfNecessary FAILED: %@", error);
NSString *localizedDescription = [error localizedDescription];
error = [NSError errorWithDomain:@"OsiriXDomain" code:0 userInfo:[NSDictionary dictionaryWithObjectsAndKeys:error, NSUnderlyingErrorKey, [NSString stringWithFormat:@"Store Configuration Failure: %@", ((localizedDescription != nil) ? localizedDescription : @"Unknown Error")], NSLocalizedDescriptionKey, nil]];
//Exit Failure
[pool release]; _loadLock = false; return nil;
}
[[_context undoManager] setLevelsOfUndo: 1];
[[_context undoManager] disableUndoRegistration];
...
我包括所有相同的框架....但_allBundles
甚至不用于创建,managedObjectModel
所以我不知道它应该做什么,除了将它们加载到内存中以便mom
在加载时可以查看它们。
完全迷失了。
帮助!
为什么我的 FetchRequest 返回的具有相同实体的对象会出现NSManagedObjects
而不是DicomStudy
s?我包括 DicomStudy.h,因此它应该在创建模型、上下文和获取请求期间看到对象。
[request setEntity: [[managedObjectModel() entitiesByName] objectForKey:@"Study"]];
提前致谢,
-斯蒂芬