Inconsistent behavior from newly added UITableView cells in Swift - ios

Question

Update: Identified the first half of the problem as exerciseNameLabel not rendering the updated text until a app restart. I removed the label element and am using cell.textLabel.text only. Problem #1 solved. Problem #2 is more clean: every time a cell is selected to view details, the indexPath.row is set to the selection and the next added item overwrites the item. Not sure of the mechanics behind indexPath.row, so I'm still searching to figure this one out. Help there is appreciated.
Short Youtube video (0:48) of the below behavior: https://www.youtube.com/watch?v=Zr4lCbzrtLY
I followed Apple's MealTracker walkthrough pretty closely, but my TableView is behaving strangely. Usually the newly created elements will only appear on the TableView after I restart the app. However, the newly created, but invisible items can be clicked. It seems like the label isn't being populated with the name after creation, but the name takes after a restart of the app. (This is shown in the first half of the video above)
Additionally, sometimes there is really unexpected behavior where a newly created item overwrites an old item (~0:32 on the video). When this happens, the label is updated in real time as expected, so the only unexpected part of this is that an old item is getting overwritten.
I have a print statement inside the tableView method which shows the correct index, the right element name, and the right array size.
class MasterTableViewController: UITableViewController {
var exercises = ExerciseProgram(name: "temp", startDate: "temp", program: nil)
override func viewWillAppear(animated: Bool) {
// Load any saved program, otherwise load sample data.
if let savedProgram = loadProgram() {
exercises = savedProgram
} else {
// Load the sample data.
loadSampleProgram()
}
}
override func viewDidLoad() {
super.viewDidLoad()
self.navigationItem.leftBarButtonItem = self.editButtonItem()
}
func loadSampleProgram() {
// snip
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return exercises!.getCount()
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cellIdentifier = "ExerciseTableViewCell"
let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! ExerciseTableViewCell
// Fetches the appropriate exercise for the data source layout
let exercise = exercises?.getExercise(indexPath.row)
cell.exerciseNameLabel.text = exercise!.name
print("in tableView() indexPath.row: \(indexPath.row) exercise name: \(exercise!.name) exercises count: \(exercises!.getCount())")
// Configure the cell...
return cell
}
// Override to support conditional editing of the table view.
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
// Return false if you do not want the specified item to be editable.
return true
}
// Override to support editing the table view.
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
if editingStyle == .Delete {
// Delete the row from the data source
exercises!.removeExercise(indexPath.row)
saveProgram()
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
} //else if editingStyle == .Insert {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
// }
}
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
if segue.identifier == "ShowDetail" {
let exerciseDetailViewController = segue.destinationViewController as! ExerciseDetailViewController
// Get the cell that generated this segue
if let selectedExerciseCell = sender as? ExerciseTableViewCell {
let indexPath = tableView.indexPathForCell(selectedExerciseCell)!
let selectedExercise = exercises!.getExercise(indexPath.row)
exerciseDetailViewController.exercise = selectedExercise
}
}
}
#IBAction func unwindToExerciseList(sender: UIStoryboardSegue) {
if let sourceViewController = sender.sourceViewController as? AddExerciseViewController, exercise = sourceViewController.exercise {
if let selectedIndexPath = tableView.indexPathForSelectedRow {
// Update an existing exercise.
exercises!.updateExercise(selectedIndexPath.row, updatedExercise: exercise)
tableView.reloadRowsAtIndexPaths([selectedIndexPath], withRowAnimation: .None)
} else {
// Add a new exercise.
let newIndexPath = NSIndexPath(forRow: exercises!.getCount(), inSection: 0)
exercises!.addExercise(exercise)
tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Bottom)
}
// Save the program.
saveProgram()
}
}
// MARK: NSCoding
func saveProgram() {
let defaults = NSUserDefaults.standardUserDefaults()
defaults.setObject(NSKeyedArchiver.archivedDataWithRootObject(exercises!), forKey: "program")
defaults.synchronize()
}
func loadProgram() -> ExerciseProgram? {
let defaults = NSUserDefaults.standardUserDefaults()
guard let decodedNSData = defaults.objectForKey("program") as? NSData,
let exerciseProgram = NSKeyedUnarchiver.unarchiveObjectWithData(decodedNSData) as? ExerciseProgram
else {
print("Failed")
return nil
}
return exerciseProgram
}
}
Add Element:
class AddExerciseViewController: UIViewController, UINavigationControllerDelegate, UITextFieldDelegate {
#IBOutlet weak var exerciseNameTextField: UITextField!
#IBOutlet weak var doneButton: UIBarButtonItem!
var exercise: Exercise?
override func viewDidLoad() {
super.viewDidLoad()
doneButton.enabled = false
exerciseNameTextField.delegate = self
// Do any additional setup after loading the view.
}
// MARK: UITextFieldDelegate
func textFieldShouldReturn(textField: UITextField) -> Bool {
// Hide the keyboard.
textField.resignFirstResponder()
return true
}
func textFieldDidEndEditing(textField: UITextField) {
checkValidExerciseName()
}
func textFieldDidBeginEditing(textField: UITextField) {
// Disable the Save button while editing.
doneButton.enabled = false
}
func checkValidExerciseName() {
// Disable the Done button if the text field is empty.
let text = exerciseNameTextField.text ?? ""
doneButton.enabled = !text.isEmpty
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func cancelButtonTapped(sender: UIBarButtonItem) {
// Depending on style of presentation (modal or push presentation), this view controller needs to be dismissed in two different ways.
let isPresentingInAddExerciseMode = presentingViewController is UINavigationController
if isPresentingInAddExerciseMode {
dismissViewControllerAnimated(true, completion: nil)
} else {
navigationController!.popViewControllerAnimated(true)
}
}
// MARK: - Navigation
// This method lets you configure a view controller before it's presented.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if doneButton === sender {
let name = exerciseNameTextField.text ?? ""
let notes = "test form notes"
let weight = 135
// Set the meal to be passed to MealListTableViewController after the unwind segue.
exercise = Exercise(name: name, notes: notes, workoutLog: nil, weight: weight)
}
}
}
ExeciseProgram:
class ExerciseProgram: NSObject, NSCoding {
var name = "Allpro Auto Regulated"
var startDate = "16-04-20"
var program: [Exercise]? = []
init?(name: String, startDate: String, program: [Exercise]?) {
self.name = name
self.startDate = startDate
if program != nil {
self.program = program
} else {
self.program = []
}
if name.isEmpty || startDate.isEmpty {
return nil
}
}
// MARK: Types
struct PropertyKey {
static let nameKey = "name"
static let startDateKey = "startDate"
static let programKey = "program"
}
// MARK: Methods
func addExercise(newExercise: Exercise) {
program!.append(newExercise)
}
func getExercise(index: Int) -> Exercise {
return program![index]
}
func getCount() -> Int {
return program!.count
}
func updateExercise(index: Int, updatedExercise: Exercise) {
program![index] = updatedExercise
}
func removeExercise(index: Int) {
program!.removeAtIndex(index)
}
// MARK: NSCoder
func encodeWithCoder(aCoder: NSCoder) {
aCoder.encodeObject(name, forKey: PropertyKey.nameKey)
aCoder.encodeObject(startDate, forKey: PropertyKey.startDateKey)
aCoder.encodeObject(program, forKey: PropertyKey.programKey)
}
required convenience init?(coder aDecoder: NSCoder) {
let name = aDecoder.decodeObjectForKey(PropertyKey.nameKey) as! String
let startDate = aDecoder.decodeObjectForKey(PropertyKey.startDateKey) as! String
let program = aDecoder.decodeObjectForKey(PropertyKey.programKey) as! [Exercise]?
// Must call designated initializer.
self.init(name: name, startDate: startDate, program: program)
Exercise:
class Exercise: NSObject, NSCoding {
var name: String
var formNotes: String?
private var workoutLog: [[String:AnyObject]]?
var currentWeights = Weights(heavy: 0)
init?(name: String, notes: String?, workoutLog: [[String:AnyObject]]?, weight: Int?) {
self.name = name
self.formNotes = notes
if (workoutLog != nil) {
self.workoutLog = workoutLog
} else {
self.workoutLog = []
}
self.currentWeights.heavy = weight!
if name.isEmpty {
return nil
}
}
// MARK: Types
// weights of the exercise
struct Weights {
var heavy = 0
var warmup25: Int { return roundToFives(Double(heavy) * 0.25) }
var warmup50: Int { return roundToFives(Double(heavy) * 0.50) }
}
struct PropertyKey {
static let nameKey = "name"
static let formNotesKey = "formNotes"
static let workoutLogKey = "workoutLog"
static let currentWeightsHeavyKey = "currentWeightsHeavy"
}
func recordWorkout(date: String, weight: Int, repsFirstSet: Int, repsSecondSet: Int) {
let newWorkoutLogEntry = ["date": date, "weight": weight, "repsFirstSet": repsFirstSet, "repsSecondSet": repsSecondSet]
workoutLog!.append(newWorkoutLogEntry as! [String : AnyObject])
}
func getLastWorkout() -> [String:AnyObject]? {
return workoutLog?.last
}
func getBarWeightsString(targetWeight: Int) -> String {
if targetWeight < 54 {
return "Bar"
} else {
return calculatePlates(roundToFives(Double(targetWeight)))
}
}
// MARK: NSCoder
func encodeWithCoder(aCoder: NSCoder) {
aCoder.encodeObject(name, forKey: PropertyKey.nameKey)
aCoder.encodeObject(formNotes, forKey: PropertyKey.formNotesKey)
aCoder.encodeObject(workoutLog, forKey: PropertyKey.workoutLogKey)
aCoder.encodeInteger(currentWeights.heavy, forKey: PropertyKey.currentWeightsHeavyKey)
}
required convenience init?(coder aDecoder: NSCoder) {
let name = aDecoder.decodeObjectForKey(PropertyKey.nameKey) as! String
let formNotes = aDecoder.decodeObjectForKey(PropertyKey.formNotesKey) as! String
let workoutLog = aDecoder.decodeObjectForKey(PropertyKey.workoutLogKey) as! [[String : AnyObject]]
let currentWeights = aDecoder.decodeIntegerForKey(PropertyKey.currentWeightsHeavyKey)
// Must call designated initializer.
self.init(name: name, notes: formNotes, workoutLog: workoutLog, weight: currentWeights)
}
}

Answer 1

Problem 1: missing cell labels for newly added exercises until app restart
The cell.exerciseNameLabel.text inside tableView() is not consistently rendering. I don't know why, but changing this to cell.labelText.text works 100% of the time.
Problem 2: newly added exercises overwriting previously selected cells
The copied code from Apple's MealTracker exercise has a case for updating an item, which is essentially overwriting its old entry. I fixed this by removing the conditional inside unwindToExerciseList(). Everything is working now.
#IBAction func unwindToExerciseList(sender: UIStoryboardSegue) {
if let sourceViewController = sender.sourceViewController as? AddExerciseViewController, exercise = sourceViewController.exercise {
// Add a new exercise.
let newIndexPath = NSIndexPath(forRow: exercises!.getCount(), inSection: 0)
exercises!.addExercise(exercise)
tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Bottom)
saveProgram()
}
}