Question

This code should save am uiimage to core data. The image is stored in it’s own entity and liked to another entity (relationship)

   NSEntityDescription *imageEntity = [ NSEntityDescription insertNewObjectForEntityForName:kImage inManagedObjectContext:self.context];
    [imageEntity setValue:self.image forKey:kPicture];

    [newPerson setValue:imageEntity forKey:kPicture];

    NSError *error;
    if (![self.context save:&error]) {
        NSLog(@"Whoops, couldn't save new associate: %@", [error localizedDescription]);
    }

Here I try to get it back , to put it in an uiimageview on a custom cell

  Person *crt = [self.fetchController objectAtIndexPath:indexPath];
    cell.name.text = crt.name;
    Image *img = crt.picture;
    cell.image.image = img.picture;

This only works when the picture is first added … after restarting the app the image does not show again.. Why is that? It’s set as a transformable attribute

Answer 1

You can add an UIImage only as binary data. So what you need to do it set your entity’s attribute type to Binary Data, and the use the CoreGraphics' method UIImagePNGRepresentation(UIImage *image), which returns NSData and save it this way. And if you want to extract it from the database, you get the NSData and create an image with [UIimage imageWithData:(NSData *data)] method.
But I think the best implementation is to store only the local path to the image in your database, but the actual file is stored in a folder in your app’s Documents folder… just a suggestion.