大佬教程收集整理的这篇文章主要介绍了ios – 实体(null)不是密钥值编码兼容的密钥“标题”，大佬教程大佬觉得挺不错的，现在分享给大家，也给大家做个参考。
CoreData: error: Failed to call designated initializer on NsmanagedObject class 'Book' *** TerminaTing app due to uncaught exception 'NSUnkNownKeyException',reason: '[<Book 0x8454560> valueForUndefinedKey:]: the entity (null) is not key value coding-compliant for the key "title".'
在我看来,它成功地找到了我的Book类,并且它有一个title属性.我究竟做错了什么？
Books.xcdatamodel
Book title: String
我在localhost有一个网址：3000 / books / initial返回以下内容(JSON)
[{title:"one"},{title:"two"}]
我正在使用mogenerator来创建我的课程.我没有在Book中添加任何东西,但是_Book显然已经定义了title属性.
最后,这是我用来加载请求的代码.
RKObjectManager* objectManager = [RKObjectManager managerWithBaseURL:[NSURL URLWithString:@"http://localhost:3000/"]]; RKManagedObjectStore* objectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:self.model]; objectManager.managedObjectStore = objectStore; // Mappings RKEntitymapping *bookMapping = [RKEntitymapping mappingForEntityForName:@"Book" inManagedObjectStore:objectStore]; [bookMapping addAttributeMappingsFromArray:@[@"title"]]; RKResponseDescriptor * responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:bookMapping pathPattern:@"books/initial/" keyPath:nil statusCodes:rKStatusCodeIndexSetForClass(RKStatusCodeClasssuccessful)]; [objectManager addResponseDescriptor:responseDescriptor]; // Send request [objectManager getObjectsAtPath:@"/books/initial/" parameters:nil success:^(RKObjectrequestOperation * operation,RKMappingResult *mappingResult) { NSLog(@"succesS"); } failure: ^(RKObjectrequestOperation * operation,NSError * error) { NSLog(@"FAILURE %@",error); }];
编辑：我在RKTwitterCoreData应用程序中找到//发送请求部分之前添加了以下行,但我仍然得到相同的错误
// Other Initialization (move this to app delegatE) [objectStore createPersistentStoreCoordinator]; [objectStore createManagedObjectContexts]; objectStore.managedObjectCache = [[RKInMemorymanagedObjectCache alloc] initWithManagedObjectContext:objectStore.persistentStoreManagedObjectContext];
见RestKit 0.20 — CoreData: error: Failed to call designated initializer on NSManagedObject class
我也忘了创建持久性商店.这是完整的工作示例：
// Core Data Example // Initialize RestKIT RKObjectManager* objectManager = [RKObjectManager managerWithBaseURL:[NSURL URLWithString:@"http://localhost:3000"]]; RKManagedObjectStore* objectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:self.model]; objectManager.managedObjectStore = objectStore; // Mappings RKEntitymapping *bookMapping = [RKEntitymapping mappingForEntityForName:@"Book" inManagedObjectStore:objectStore]; [bookMapping addAttributeMappingsFromArray:@[@"title"]]; RKResponseDescriptor * responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:bookMapping pathPattern:@"/books/initial/" keyPath:nil statusCodes:rKStatusCodeIndexSetForClass(RKStatusCodeClasssuccessful)]; [objectManager addResponseDescriptor:responseDescriptor]; // Other Initialization (move this to app delegatE) [objectStore createPersistentStoreCoordinator]; NSString *storePath = [RKApplicationDataDirectory() StringByAppendingPathComponent:@"RKTwitter.sqlite"]; NSString *seedPath = [[NSBundle mainBundle] pathForresource:@"RKSeedDatabase" ofType:@"sqlite"]; NSError *error; NSPersistentStore *persistentStore = [objectStore addsqlitePersistentStoreAtPath:storePath fromSeedDatabaseAtPath:seedPath withConfiguration:nil options:nil error:&error]; NSAssert(persistentStore,@"Failed to add persistent store with error: %@",error); [objectStore createManagedObjectContexts]; objectStore.managedObjectCache = [[RKInMemorymanagedObjectCache alloc] initWithManagedObjectContext:objectStore.persistentStoreManagedObjectContext]; // Send request [objectManager getObjectsAtPath:@"/books/initial/" parameters:nil success:^(RKObjectrequestOperation * operation,error); }];
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