Swift 错误

转载自http://blog.csdn.net/longhai0long/article/details/38379247

刚看swift开发IOS，在使用Core Data框架时遇到了一个问题，控制台打出的log 如下：

CoreData: warning: Unable to load class named 'CollectNews' for entity 'CollectNews'.  Class not found, using default NSManagedObject instead.

百思不得其解，后来在StackOverFlow上找到了一种解决办法，就是在Model类的开关加上这个的注解：

@objc(CollectNews) 

Demo的部分代码分享给大家，仅做参考：
Model类

import Foundation    
import CoreData  

@objc(CollectNews)    
class CollectNews: NSManagedObject {      
    @NSManaged var date: NSNumber    
    @NSManaged var newsId: NSNumber    
} 

AppDelegate类：

func application(application: UIApplication!, didFinishLaunchingWithOptions launchOptions: NSDictionary!) -> Bool {      
    insertData()    
    selectData()      
    return true    
}    
    
//插入数据    
func insertData(){      
    //取Entity对象    
    var collectNews = NSEntityDescription.insertNewObjectForEntityForName("CollectNews", inManagedObjectContext: self.managedObjectContext) as CollectNews    
    
    //对属性进行修改    
    collectNews.newsId = 12    
    collectNews.date = 20140805    
    
    //保存    
    if self.managedObjectContext.hasChanges{    
        self.managedObjectContext.save(nil)    
    }    
}    
    
//查询    
func selectData(){    
    //得request对象    
    var request = NSFetchRequest()    
    var entityQueue = NSEntityDescription.entityForName("CollectNews", inManagedObjectContext: self.managedObjectContext)    
    request.entity = entityQueue    
    var errorInfo:NSError?    
    //取结果集    
    var resultArr = self.managedObjectContext.executeFetchRequest(request, error: &errorInfo) as NSArray    
    
    println("----》(resultArr.count)")    
    
    var temp = resultArr[0] as CollectNews    
    
    println("--->(temp.newsId)")    
}