Coredata错误“数据：<故障>”

Question

我尝试使用以下代码从CoreData中提取数据NSFetchRequest *request = [[NSFetchRequest alloc] init];request.entity = [NSEntityDescription entityForName:@"Cave" inManagedObjectContext:self.context];request.predicate = [NSPredicate predicateWithFormat:@"(latitude > 0) AND (longitude > 0)"];NSError *error;NSLog(@"%@",[self.context executeFetchRequest:request error:&error]);NSLog(@"%@",[error localizedDescription]);CoreData应该具有9个匹配的对象，并找到9个对象。所以谓词应该起作用，但是我在控制台中得到了2011-09-05 07:41:42.267 CaveConditions[6930:11903] (    "<NSManagedObject: 0x7368060> (entity: Cave; id: 0x7367880 <x-coredata://C825FC9D-3490-4D8A-A811-979B819A2EB6/Cave/p31> ; data: <fault>)",    "<NSManagedObject: 0x73547e0> (entity: Cave; id: 0x7356e20 <x-coredata://C825FC9D-3490-4D8A-A811-979B819A2EB6/Cave/p40> ; data: <fault>)",    "<NSManagedObject: 0x73681e0> (entity: Cave; id: 0x7363e60 <x-coredata://C825FC9D-3490-4D8A-A811-979B819A2EB6/Cave/p42> ; data: <fault>)",    "<NSManagedObject: 0x7368280> (entity: Cave; id: 0x7356be0 <x-coredata://C825FC9D-3490-4D8A-A811-979B819A2EB6/Cave/p72> ; data: <fault>)",    "<NSManagedObject: 0x7368320> (entity: Cave; id: 0x733ad80 <x-coredata://C825FC9D-3490-4D8A-A811-979B819A2EB6/Cave/p73> ; data: <fault>)",    "<NSManagedObject: 0x73683c0> (entity: Cave; id: 0x7333e70 <x-coredata://C825FC9D-3490-4D8A-A811-979B819A2EB6/Cave/p91> ; data: <fault>)",    "<NSManagedObject: 0x7368480> (entity: Cave; id: 0x7361810 <x-coredata://C825FC9D-3490-4D8A-A811-979B819A2EB6/Cave/p101> ; data: <fault>)",)在我对Cave.m（即实体）进行以下更改之前，它一直运行良好我在Cave.h中将MKAnnotation添加为委托，并在Cave.m中添加了此代码。- (CLLocationCoordinate2D)coordinate{    CLLocationCoordinate2D location;    location.latitude = [self.latitude doubleValue];    location.longitude = [self.longitude doubleValue];    return location;}有办法调试吗？

Answer 1

从CoreData提取数据时，我遇到了同样的问题！因此，我按照@jrturton的指示在Swift 3中实现了它：

步骤1：新增 import CoreData

步骤2：添加以下代码。。

let context = ( UIApplication.shared.delegate as! AppDelegate ).persistentContainer.viewContext

var request = NSFetchRequest<NSFetchRequestResult>()

request = Your_Entity_Name.fetchRequest()

request.returnsObjectsAsFaults = false

do {

    let arrayOfData = try context.fetch(request)

} catch {

    // Handle the error! 

}

希望会对您有帮助。:)