将核心数据添加到现有的iPhone项目中

Question

我想将核心数据添加到现有的iPhone项目中，但我仍然遇到很多编译错误：- NSManagedObjectContext undeclared - Expected specifier-qualifier-list before 'NSManagedObjectModel' - ...我已经将核心数据框架添加到目标（右键单击我的项目“Targets”，“Add” - “Existing Frameworks”，“CoreData.framework”）。我的头文件：NSManagedObjectModel *managedObjectModel;NSManagedObjectContext *managedObjectContext;       NSPersistentStoreCoordinator *persistentStoreCoordinator;[...]@property (nonatomic, retain, readonly) NSManagedObjectModel *managedObjectModel;@property (nonatomic, retain, readonly) NSManagedObjectContext *managedObjectContext;@property (nonatomic, retain, readonly) NSPersistentStoreCoordinator *persistentStoreCoordinator;我错过了什么？开始一个新项目不是一个选择......非常感谢！编辑 对不起，我确实有这些实现...但似乎缺少库...实现方法已满，编译错误如“ managedObjectContext undeclared”，“ NSPersistentStoreCoordinator undeclared”，但也有“预期”）'之前NSManagedObjectContext“（虽然它似乎括号是正确的）...#pragma mark -#pragma mark Core Data stack/** 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;}/** Returns the managed object model for the application. If the model doesn't already exist, it is created by merging all of the models found in     application bundle. */- (NSManagedObjectModel *)managedObjectModel {    if (managedObjectModel != nil) {        return managedObjectModel;    }    managedObjectModel = [[NSManagedObjectModel mergedModelFromBundles:nil] retain];        return managedObjectModel;}