无法从coredata获取数据

Question

我从照片库中获取图像并将其保存到核心数据,然后将其显示到图像视图.这是正确的工作.但是当我再次运行项目时,图像没有显示在我的图像视图上.

这是从照片库中获取图像的代码

   -(void)imagePickerController:(UIImagePickerController *)picker   didFinishPickingMediaWithInfo:(NSDictionary *)info


{

 [picker dismissModalViewControllerAnimated:YES];



   UIImage *img= [info objectForKey:@"UIImagePickerControllerOriginalImage"];


NSManagedObjectContext *context=[self managedObjectContext];

NSManagedObject *newContact=[[NSManagedObject alloc] initWithEntity:[NSEntityDescription entityForName:@"Contacts" inManagedObjectContext:context] insertIntoManagedObjectContext:context];
//newContact = [NSEntityDescription insertNewObjectForEntityForName:@"Images" inManagedObjectContext:context];

NSData *data=UIImageJPEGRepresentation(img,0.0);
[newContact setValue:data forKey:@"image"];
[self fetchData];

}

这是fetchData()方法的代码.

 -(void)fetchData
{
 NSManagedObjectContext *context=[self managedObjectContext];

    NSFetchRequest * request = [[NSFetchRequest alloc] init];
[request setEntity:[NSEntityDescription entityForName:@"Contacts"
                               inManagedObjectContext:context]];
NSError * error = nil;
NSArray * objects = [context executeFetchRequest:request error:&error];
if ([objects count] > 0) {
    NSManagedObject *managedObject = objects[0];
    data1 = [managedObject valueForKey:@"image"];
    image2 = [[UIImage alloc]initWithData:data1];
    _imageView.image=image2;
}

}

这是我的viewDidLoad()

- (void)viewDidLoad
{
[super viewDidLoad];
[self fetchData];

// Do any additional setup after loading the view.
}

Answer 1

首先,您应该将图像路径(不是uiimage)保存到Core Data,然后从Core Data获取路径并通过此路径将图像加载到imageView.

并使用Magical Record(https://github.com/magicalpanda/MagicalRecord)来管理核心数据,您将完全没有问题.