Core Data Image with Custom TableViewCell in Swift - swift

Question

I am new to Swift and iOS Development, and have not found a specific answer to my question.
I am attempting to populate a custom tableview with 3 Labels and 2 Images using Core Data.
I read up on optionals and have even built something similar to what I am trying to do now using the Subtitle option when creating the cell in the storyboard. That works.
My Core Data set up looks like this at the top of the class:
// MARK: - Managed Object Context
var moc = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
// Initialize Fetch Results
var fetchedResultsController = NSFetchedResultsController()
func fetchRequest() -> NSFetchRequest {
let fetchRequest = NSFetchRequest(entityName: "Custom")
let sortDescriptor = NSSortDescriptor(key: "customFourImages", ascending: true)
fetchRequest.sortDescriptors = [sortDescriptor]
return fetchRequest
}
// MARK: - Retrieve Request
func getFetchRequest() -> NSFetchedResultsController {
fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest(), managedObjectContext: moc!, sectionNameKeyPath: nil, cacheName: nil)
return fetchedResultsController
}
My viewDidLoad and viewDidAppear look like this:
// MARK: - Fetch
fetchedResultsController = getFetchRequest()
fetchedResultsController.delegate = self
do {
try fetchedResultsController.performFetch()
} catch {
print("Failed to Perform Initial Fetch")
return
}
self.tableView.reloadData()
Finally, my cellForRowAtIndexPath looks like this:
// MARK: - Dequeue Reusable Cell
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! CustomTableViewCell
// MARK: - Initiate Fetch Results for Index Path
let custom = fetchedResultsController.objectAtIndexPath(indexPath) as! Custom
let customLabel = custom.customLabels
let customTwoLabel = custom.customTwoLabels
let customThreeLabel = custom.customThreeLabels
let image = UIImage(named: "Custom Food")
let imageData = UIImagePNGRepresentation(image!)
custom.customFourImages = imageData
let images = UIImage(named: "Custom Drink")
let imagesData = UIImagePNGRepresentation(images!)
custom.customFiveImages = imagesData
// MARK: - Set Items in Cell to Returned Fetched Results
cell.customLabel?.text = "\(customLabel)"
cell.customTwoLabel?.text = "\(customTwoLabel)"
cell.customThreeLabel?.text = "\(customThreeLabel)"
cell.imageView?.image = UIImage(data: custom.customFourImages!)
cell.imageView?.image = UIImage(data: custom.customFiveImages!)
return cell
}
I have tried every permutation that I can think of and have scoured the Internet and StackOverflow for a specific answer. I would also prefer not to use Strings. I am using imagePickerController. But even with images in my imageAssets, e.g. "Custom Food", "Custom Drink", image is still found nil.
I can't crack it!

Answer 1

From your comments I can't workout where you are actually saving your managed objects to Core Data. you mention that you use try.moc?.save() but are you saving your individual images to core data? Furthermore, if your images are stored locally in the device, and not fetched from an URL, then you don't really need core data for this.
In the case that you are fetching your images from a URL or whatever, and assuming that you have added an entity MyImage with a imageData property of type NSData, you need to save the object like so:
class func createInManagedObjectContext(moc: NSManagedObjectContext, imgData: NSData) ->MyImage {
let newItem = NSEntityDescription.insertNewObjectForEntityForName("MyImage", inManagedObjectContext: moc) as! MyImage
newItem.imageData = imagData
return newItem
}
Add that function to your MyImage.Swift file (generated by Core Data), so that when you need to save a new image to core data you just do:
func saveNewImage(data: {DATA}){
MyImage.createInManagedObjectContext(self.managedObjectContext, imgData: data);
}
Then, to fetch your objects:
func getSavedImages() -> [MyImage]? {
fetchRequest.sortDescriptors = [sortDescriptor]
do {
return try self.managedObjectContext.executeFetchRequest(fetchRequest) as? [MyImage]
} catch {
print("no records found")
return nil
}
}
If you are already doing this, can you please update your code with more details? pointing out where your error is happening (line number).
If your Image is failing here:
cell.imageView?.image = UIImage(data: custom.customFourImages!)
cell.imageView?.image = UIImage(data: custom.customFiveImages!)
Your fetch result is not getting records from Core Data, which is probably an issue with the above.
if your code is failing here:
let images = UIImage(named: "Custom Drink")
let imagesData = UIImagePNGRepresentation(images!)
You should be unwraping your images object with an if let img = images { ... } and most likely the error would be related to the name of the UIImage that you are getting from memory.
I hope this helps.
Cheers.
EDIT 1:
In reply to your comments:
try.moc.save will not save your images, it will persist any changes pending in the data model.
You need to actually create the managed object in core data, and you need to make sure that your fetch request is getting the relevant data out of Core Data.
Your code is failing because customFourImages is nil. Which in term comes from:
let image = UIImage(named: "Custom Food")
let imageData = UIImagePNGRepresentation(image!)
custom.customFourImages = imageData
....
let images = UIImage(named: "Custom Drink")
let imagesData = UIImagePNGRepresentation(images!)
custom.customFiveImages = imagesData
...
cell.imageView?.image = UIImage(data: custom.customFourImages!)
cell.imageView?.image = UIImage(data: custom.customFiveImages!)
This all seems a bit redundant.
Try this:
let image = UIImage(named: "Custom Food")
let imageData = UIImagePNGRepresentation(image!)
cell.imageView?.image = image
custom.createInManagedObjectContext(moc, imgData: imageData)
....
let images = UIImage(named: "Custom Drink")
let imagesData = UIImagePNGRepresentation(images!)
cell.imageView?.image = images //this is called in the same block? you are overwriting your imageView in the cell, maybe you have two?
custom.createInManagedObjectContext(moc, imgData: imagesData)
This will save the images to Core data and assign the right image to your cell view (I'm unsure if this will address your needs of saving images data to core data). Make sure you understand why you need to use core data and save the appropriate managed object that suits your requirements.