Swift CoreData passing selected row value between UITableViews - ios

Question

I'm new to Swift and coding, only about a month in and I am trying to build some simple UItableViews to set up some CoreData attributes.
The structure of my CoreData entities is a many-to-many relationship between the Workouts Entity and the Exercises Entity. (I would post some images but I don't have a high enough rep!)
What I'm trying to achieve is a simple settings menu where users can create a Workout and then create a series of Exercises within that Workout by using tableViews with a navigationController at the top (just like the iOS settings menu)
Currently I've got it working so that you can add some Workouts and then you can go to the Excercises tableView to add some Exercises. However I haven't been able to do two things:
1) How can I ensure that when a user adds an Exercise that it is assigned to the correct Workout that they've selected from the previous tableView?
2) How can I ensure that the Exercise tableView only shows Exercises of the Workout that they've selected?
I've done a lot of reading around the subject and think the answer is something to do with the segue from Workouts to Exercises (to pass the workoutName to the Exercises tableView by using a delegate? And then using NSPredicate to limit the Exercises shown to the Workout selected?
I'm not 100% sure, but any help would be greatly appreciated!
Here's the code for the segue from Workouts to Exercises:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
if segue.identifier == "excerciseMaster" {
let ExcerciseMasterTableViewController = segue.destinationViewController as UIViewController
let indexPath = tableView.indexPathForSelectedRow()!
let workout = workouts[indexPath.row]
let destinationTitle = workout.workoutName
ExcerciseMasterTableViewController.title = destinationTitle
}
}
Here's the code for my Exercises tableViewController:
import UIKit
import CoreData
class ExcerciseMasterTableViewController: UITableViewController {
// Create an empty array of Excercises
var excercises = [Excercises]()
// Retreive the managedObjectContext from AppDelegate
let managedObjectContext = (UIApplication.sharedApplication().delegate as AppDelegate).managedObjectContext
override func viewDidLoad() {
super.viewDidLoad()
// Use optional binding to confirm the managedObjectContext
if let moc = self.managedObjectContext {
}
fetchExcercises()
}
func fetchExcercises() {
let fetchRequest = NSFetchRequest(entityName: "Excercises")
// Create a sort descriptor object that sorts on the "excerciseName"
// property of the Core Data object
let sortDescriptor = NSSortDescriptor(key: "excerciseName", ascending: true)
// Set the list of sort descriptors in the fetch request,
// so it includes the sort descriptor
fetchRequest.sortDescriptors = [sortDescriptor]
if let fetchResults = managedObjectContext!.executeFetchRequest(fetchRequest, error: nil) as? [Excercises] {
excercises = fetchResults
}
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// How many rows are there in this section?
// There's only 1 section, and it has a number of rows
// equal to the number of excercises, so return the count
return excercises.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = self.tableView.dequeueReusableCellWithIdentifier("Excercise Cell", forIndexPath: indexPath) as UITableViewCell
// Get the Excercises for this index
let excercise = excercises[indexPath.row]
// Set the title of the cell to be the title of the excercise
cell.textLabel!.text = excercise.excerciseName
cell.detailTextLabel!.text = "\(excercise.sets)x\(excercise.reps)"
cell.accessoryType = UITableViewCellAccessoryType.DisclosureIndicator
return cell
}
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
if(editingStyle == .Delete ) {
// Find the Excercise object the user is trying to delete
let excerciseToDelete = excercises[indexPath.row]
// Delete it from the managedObjectContext
managedObjectContext?.deleteObject(excerciseToDelete)
// Refresh the table view to indicate that it's deleted
self.fetchExcercises()
// Tell the table view to animate out that row
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Automatic)
save()
}
}
// MARK: UITableViewDelegate
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let excercise = excercises[indexPath.row]
}
let addExcerciseAlertViewTag = 0
let addExcerciseTextAlertViewTag = 1
#IBAction func addExcerciseButton(sender: AnyObject) {
var namePrompt = UIAlertController(title: "Add Excercise",
message: "Enter Name",
preferredStyle: .Alert)
var excerciseNameTextField: UITextField?
namePrompt.addTextFieldWithConfigurationHandler {
(textField) -> Void in
excerciseNameTextField = textField
textField.placeholder = "Title"
}
namePrompt.addAction(UIAlertAction(title: "Ok",
style: .Default,
handler: { (action) -> Void in
if let textField = excerciseNameTextField {
self.saveNewItem(textField.text, workoutName: "Workout A")
}
}))
self.presentViewController(namePrompt, animated: true, completion: nil)
}
func saveNewItem(excerciseName : String, workoutName: String) {
// Create the new excercise item
var newExcercise = Excercises.createExcerciseInManagedObjectContext(self.managedObjectContext!, name: excerciseName)
println(excerciseName)
println(workoutName)
// Update the array containing the table view row data
self.fetchExcercises()
// Animate in the new row
// Use Swift's find() function to figure out the index of the newExcercise
// after it's been added and sorted in our Excercises array
if let newExcerciseIndex = find(excercises, newExcercise) {
// Create an NSIndexPath from the newExcerciseIndex
let newExcerciseIndexPath = NSIndexPath(forRow: newExcerciseIndex, inSection: 0)
// Animate in the insertion of this row
tableView.insertRowsAtIndexPaths([ newExcerciseIndexPath ], withRowAnimation: .Automatic)
save()
}
}
func save() {
var error : NSError?
if(managedObjectContext!.save(&error) ) {
println(error?.localizedDescription)
}
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
if segue.identifier == "excerciseSettings" {
let ExcerciseSettingsDetailViewController = segue.destinationViewController as UIViewController
let indexPath = tableView.indexPathForSelectedRow()!
let excercise = excercises[indexPath.row]
let destinationTitle = excercise.excerciseName
ExcerciseSettingsDetailViewController.title = destinationTitle
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

Answer 1

1.The segue is close. Your ExcerciseMasterTableViewController doesn't have a property named workout. You need to add
var workout:Workout!
to your ExcerciseMasterTableViewController.
Your seque should look more like this
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
if segue.identifier == "excerciseMaster" {
let desitnationController = segue.destinationViewController as ExcerciseMasterTableViewController
let indexPath = tableView.indexPathForSelectedRow()!
let workout = workouts[indexPath.row]
destinationController.workout = workout
let destinationTitle = workout.workoutName
desitnationController.title = destinationTitle // Usually you would put this in the viewDidLoad method of the destinationController
}
}
Then in your when you add exercises in your ExcerciseMasterTableViewController simply set their workout property
workout.exercises = exercises // See note in #2
To make sure only the correct exercises are shown, in your viewDidLoad set your exercises array to workout.exercises. Note that workout.exercises should be an NSSet, so you either need to convert your set to an array, or have exercises be of type NSSet instead of an array.