2

I'm new using Core Data. I have the class Chat (subclass of NSManagedObject) and I need to create new objects with it.

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>

@interface Chat : NSManagedObject

@property (nonatomic, retain) NSString *chatID;
@property (nonatomic, retain) NSString *modified;
@property (nonatomic, retain) NSString *opponentID;
@property (nonatomic, retain) NSString *opponentFacebookID;
@property (nonatomic, retain) NSString *opponentName;
@property (nonatomic, retain) NSString *lastMessage;

@end

#import "Chat.h"

@implementation Chat

@dynamic chatID;
@dynamic modified;
@dynamic opponentID;
@dynamic opponentFacebookID;
@dynamic opponentName;
@dynamic lastMessage;

- (id)init {
    if (self = [super init])
    {
    }
    return self;
}

@end

I insert the objects like this:

Chat *chat = (Chat *)[NSEntityDescription insertNewObjectForEntityForName:@"Chat" inManagedObjectContext:[[DataManager sharedInstance] managedObjectContext]];
chat.chatID = [chatDict objectForKey:@"id"];
chat.modified = [chatDict objectForKey:@"modified"];
chat.lastMessage = [chatDict objectForKey:@"last_message"];

but my application crashes when setting chat.chatId. It shows me this error and can't figure out what to do to fix it!

2013-06-18 12:01:25.625 MyApp[5477:907] -[Chat setChatID:]: unrecognized selector sent to instance 0x1d8661d0
2013-06-18 12:01:25.627 MyApp[5477:907] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Chat setChatID:]: unrecognized selector sent to instance 0x1d8661d0'
4

2 回答 2

1

这可能意味着这chatID不是核心数据模型检查器中定义的属性的实际名称。

我总是建议让 Xcode（或“mogenerator”之类的工具）生成托管对象子类文件，而不是“手动”编写它们。

于 2013-06-18T15:16:19.620 回答
1

无法识别的选择器意味着应用程序试图告诉对象执行它没有的功能（例如，尝试修改标签的图像，它没有图像属性，因此它会抛出无法识别的选择器）。在错误消息中，它尝试使用不存在的 setChatID。我在这台计算机上没有我的 xcode 项目，所以我无法检查我的核心数据样本，但我建议重新制作 Chat 对象并使用 GUI 创建所需的属性，然后自动创建类。如果您希望我提供更多帮助，请告诉我，今天晚些时候，当我有另一台计算机时，我会再次检查。

于 2013-06-18T15:22:37.593 回答