save images to core data using magical record - image

Question

I'm using magical record with Core Data.
In my app I have just one entity with some string attributes. Now, I would like to add an image to this entity, but I don't have any idea of how to do that using magical record. I searched but haven't found anything on the web. In my app all the data is inserted by the user, so also the image, by the camera or the photo library.
How do I store images using Magical Record and Core Data?

Answer 1

Just store the image in the documents folder of the app and save a string with the file url in the core data entity.

Answer 2

What you're trying above can be done easily. Best advice i can give you is make a new sample project just to save and retrieve image from the CoreData database. That way you know exactly how the process works. If you try to embed this functionality in your current project you might loose track of what happening where.
This is very quick example, i'll expect you to import the Delegates in your .h files yourself etc.
First initiate the UIImagePicker via button
-(IBAction)pickImage:(id)sender
{
UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
imagePicker.delegate = self;
[self presentModalViewController:imagePicker animated:YES];
}
Once the image is selected, you can display it on the button using one of the delegate methods
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)selectedImage editingInfo:(NSDictionary *)editingInfo
self.imageButton.imageView.image = selectedImage;
To save it to CoreData assign your UIImage type to a Transformable type in your attribute in your database and then save the managedObjectContext
Links to help you:
UIImagePicker Class Reference
Magical Record Docs
CoreData Recipes Sample Project
Hope this help, good luck!

Answer 3

I found my answer:
to save:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString*nomeImmagine = [[NSString alloc] initWithFormat:#"%#", self.fieldName.text];
NSString *pngFilePath = [NSString stringWithFormat:#"%#/%#.png",documentsDirectory, nomeImmagine];
UIImage *image = self.showSelectedImage.image; // imageView is my image from camera
NSData *data1 = [NSData dataWithData:UIImagePNGRepresentation(image)];
[data1 writeToFile:pngFilePath atomically:NO];
to load:
-(void) loadImageFromPathInsideView
{
// [self loadImageFromPathInsideView];
Ricetta* contact =[[DataManager sharedClass]dammiTuttaLaRicetta:self.indice];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString*nomeImmagine = [[NSString alloc] initWithFormat:#"%#", contact.nome2];
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString* path = [NSString stringWithFormat:#"%#/%#.png",documentsDirectory, nomeImmagine];;
UIImage* image = [UIImage imageWithContentsOfFile:path];
self.image.image = image;
}

Answer 4

a word of advice. storing images as transformable (aka NSImage) type in core data is easy, but leads to overall slow app performance for even a low number (over 20) that range from 50k to 200kb with an average of 100k. even having those files linked via a relationship is slow, considering that one controller is often bound to another.
the above method of storing a local path name as a NSString pointing to Documents folder is heaps better for the overall experience.
that being said, creating a thumbnail image (of around 150x150) can be advantageous to create once and store that as a transient transformable NSImage, rather than loading the biggy and doing an on-the-fly resize a number of times. that performance can be observed easily scrolling up and down in a Table holding 50+ thumbnail images.