UItableview Cell changes data and attributes randomly or while scrolling - ios

Question

I've been trying to tackle this issue for hours, I know my code isn't the fanciest but i just can't seem to pin point the problem. I have an array of NSmanagedobject that has attributes in it. if the attribute of "isComplete" is true i want the background color of my cell to be green. I have a custom view that creates a new nsmanaged object and adds it to the tableview. where by default it should add a white background cell. I know there's a lot of code to explain but it's been hours and i just can't figure out why my tableview is loading the cells data and configuration incorrectly. this is my view controller with the tableview inside.
import CoreData
import UIKit
var coreTasks: [NSManagedObject] = []
var taskAdditionView:TaskAdditionView!
let appDel : AppDelegate = UIApplication.shared.delegate as! AppDelegate
let context: NSManagedObjectContext = appDel.persistentContainer.viewContext
class HomeViewController: UIViewController {
#IBOutlet var addTaskFunction: UIBarButtonItem!
#IBOutlet var homeTableView: UITableView!
var todaysdeadlineLabel: UILabel!
#IBAction func addTaskFunctions(_ sender: UIBarButtonItem) {
animateIn()
addTaskFunction.isEnabled = false
}
func animateIn(){
taskAdditionView = TaskAdditionView() // the view where i create a new nsmanaged object
view.addSubview(taskAdditionView)
view.bringSubviewToFront(taskAdditionView)
}
func tableviewsConstraints(){
homeTableView.translatesAutoresizingMaskIntoConstraints = false
homeTableView.layer.cornerRadius = 4
homeTableView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 20).isActive = true
homeTableView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: -20).isActive = true
homeTableView.topAnchor.constraint(equalTo: self.view.topAnchor, constant: 120).isActive = true
homeTableView.heightAnchor.constraint(equalToConstant: homeTableView.rowHeight * 3).isActive = true
homeTableView.layer.borderWidth = 0.5
homeTableView.layer.borderColor = UIColor
.black.cgColor
}
override func viewDidLoad() {
super.viewDidLoad()
loadTasks()
tableviewsConstraints()
NotificationCenter.default.addObserver(self, selector: #selector(reloadTable), name: NSNotification.Name(rawValue: "reloadTableNotification"), object: nil)
homeTableView.delegate = self
homeTableView.dataSource = self
UNUserNotificationCenter.current().requestAuthorization(options: [.alert,.sound,.badge]) { (didallow, error) in
}
}
#objc func reloadTable(notification:Notification){
animateOut()
DispatchQueue.main.async {
self.homeTableView.reloadData()
self.addTaskFunction.isEnabled = true
print("reloadTable() fired!")
}
}
}
extension HomeViewController: UITableViewDelegate,UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return coreTasks.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let task = coreTasks[indexPath.row] // creating a new task from the already stored task depending on the indexpath.row if indexPath.row is 3 then the task is tasks[3]
let cell = tableView.dequeueReusableCell(withIdentifier: "taskCell") as! CustomCell // setting the identifier ( we have already set in the storyboard, the class of our cells to be our custom cell)
cell.setTask(task: task) // this changes the label and date text since an instance of the task contains both the task and the date
print("CellData Task :", task.value(forKey: "isComplete") as! Bool, task.value(forKey: "name") as! String)
if (task.value(forKey: "isComplete") as! Bool == true){
cell.labelsToYellow()
cell.backgroundColor = Colors.greencomplete
cell.selectionStyle = .none
}
return cell
}
// Leading Swipe Action
func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
let task = coreTasks[indexPath.row]
let complete = markComplete(at: indexPath)
if !(task.value(forKey: "isComplete") as! Bool){
return UISwipeActionsConfiguration(actions: [complete])
} else {
return UISwipeActionsConfiguration(actions: [])
}
}
// Mark as Completed Task
func markComplete(at: IndexPath) -> UIContextualAction {
let df = DateFormatter()
df.dateFormat = "dd-MM-yyyy" // assigning the date format
let now = df.string(from: Date()) // extracting the date with the given format
let cell = homeTableView.cellForRow(at: at) as! CustomCell
let task = coreTasks[at.row]
let completeActionImage = UIImage(named: "AddTask")?.withTintColor(.white)
let action = UIContextualAction(style: .normal, title: "Complete") { (action, view, completion) in
task.setValue(!(task.value(forKey: "isComplete") as! Bool), forKey: "isComplete")
self.homeTableView.cellForRow(at: at)?.backgroundColor = task.value(forKey: "isComplete") as! Bool ? Colors.greencomplete : .white
cell.backgroundColor = Colors.greencomplete
cell.labelsToYellow()
task.setValue("Finished " + now, forKey: "date")
do {
try
context.save()
self.homeTableView.reloadData()
} catch {
print("Markcomplete save error")
}
// cell.displayIcons(task: task)
completion(true)
}
//action.image = #imageLiteral(resourceName: "AddTask")
action.image = completeActionImage
action.backgroundColor = Colors.greencomplete
return action
}
// Trailing Swipe Actions
func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
let task = coreTasks[indexPath.row]
let important = importantAction(at: indexPath)
let delete = deleteAction(at: indexPath)
if task.value(forKey: "isComplete") as? Bool == true {
return UISwipeActionsConfiguration(actions: [delete])
} else {
return UISwipeActionsConfiguration(actions: [delete,important])
}
}
// Delete Action
func deleteAction(at: IndexPath) -> UIContextualAction {
// remove !!!! from coredata memory as well not just array
let deleteActionImage = UIImage(named: "Delete")?.withTintColor(.white)
let action = UIContextualAction(style: .destructive , title: "Delete") { (action, view, completion) in
let objectToDelete = coreTasks.remove(at: at.row)
context.delete(objectToDelete)
self.homeTableView.deleteRows(at: [at], with: .automatic)
do {
try
context.save()
} catch {
print("Problem while saving")
}
completion(true)
}
action.image = deleteActionImage
action.backgroundColor = Colors.reddelete
return action
}
func loadTasks(){
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Tasks")
do {
coreTasks = try context.fetch(request) as! [NSManagedObject]
print("loadTasks() fired!")
} catch let error as NSError {
print("Could not fetch. \(error), \(error.userInfo)")
}
}
}
and this is my taskAddition view
import UserNotifications
import UIKit
import CoreData
class TaskAdditionView: UIView {
var importanceSegmentControl: CustomSegmentControl!
var headerLabel:UILabel!
var taskTextField: CustomTextField!
var submitButton:CustomButton!
var reminderSwitch: UISwitch!
var datePicker: UIDatePicker!
var dateSelected: Date?
var importanceValue: Int16 = 0
override init(frame: CGRect) {
super.init(frame: frame)
} // initiliaze the view like this TaskAdditionView()
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
func setupSwitchPicker(){
reminderSwitch = UISwitch()
reminderSwitch.transform = CGAffineTransform(rotationAngle: CGFloat.pi/2)
datePicker = UIDatePicker()
datePicker.minimumDate = Date()
datePicker.addTarget(self, action: #selector(pickingDate(sender:)), for: .valueChanged)
}
#objc func pickingDate(sender: UIDatePicker){
self.dateSelected = sender.date
print("Date selected: \(dateSelected)")
}
func setupLabel(){
headerLabel = UILabel()
headerLabel?.text = "Add Task"
headerLabel.textAlignment = .center
headerLabel.textColor = .black
headerLabel?.font = UIFont(name: "AvenirNext-Bold", size: 30.0)
headerLabel?.backgroundColor = UIColor.clear
}
#objc func indexChanged(control : CustomSegmentControl) {
// This all works fine and it prints out the value of 3 on any click
switch control.selectedIndex {
case 0:
importanceValue = 0
print(importanceValue)
case 1:
importanceValue = 1
print(importanceValue)
case 2:
importanceValue = 2
print(importanceValue)
default:
break;
} //Switch
} // indexChanged for the Segmented Control
func setupSegmentControl(){
importanceSegmentControl = CustomSegmentControl()
importanceSegmentControl.addTarget(self, action: #selector(indexChanged(control:)),for: UIControl.Event.valueChanged)
}
func setupButton(){
let myAttributes = [ NSAttributedString.Key.font: UIFont(name: "AvenirNext-DemiBold", size: 18.0)! , NSAttributedString.Key.foregroundColor: UIColor.white ]
let myTitle = "Add"
let myAttributedTitle = NSAttributedString(string: myTitle, attributes: myAttributes)
submitButton = CustomButton()
submitButton.setAttributedTitle(myAttributedTitle, for: .normal)
submitButton.addTarget(self, action: #selector(submitFunction(sender:)), for: .touchUpInside)
}
// Submit Function
#objc func submitFunction(sender: CustomButton){
print("Worked")
submitButton.shake()
NotificationCenter.default.post(name: NSNotification.Name("reloadTableNotification") , object: nil)
addTask()
if (reminderSwitch.isOn){
setupNotification()
print(dateSelected)
}
NSLayoutConstraint.deactivate(self.constraints)
removeFromSuperview()
}
func setupTextField(){
taskTextField = CustomTextField()
}
func setupConstraints(){
setupLabel()
setupTextField()
setupSegmentControl()
setupButton()
setupSwitchPicker()
addSubview(headerLabel!)
addSubview(importanceSegmentControl!)
addSubview(taskTextField)
addSubview(submitButton)
reminderSwitch.transform = reminderSwitch.transform.rotated(by: -(.pi/2))
addSubview(reminderSwitch)
addSubview(datePicker)
}
override func didMoveToSuperview() {
setupConstraints()
}
override func removeFromSuperview() {
for view in self.subviews{
view.removeFromSuperview()
}
NSLayoutConstraint.deactivate(self.constraints)
removeAllConstraintsFromView(view: self)
}
func addTask(){
let df = DateFormatter()
df.dateFormat = "dd-MM-yyyy" // assigning the date format
let now = reminderSwitch.isOn ? "Deadline " + df.string(from: dateSelected!) : df.string(from: Date()) // extracting the date with the given format
print("Reminder Switch is ON: ", reminderSwitch.isOn)
// Adding a task to the array
let entity =
NSEntityDescription.entity(forEntityName: "Tasks",
in: context)!
let newTask = NSManagedObject(entity: entity, insertInto: context)
newTask.setValue(taskTextField.text!, forKey: "name")
newTask.setValue(false, forKey: "isComplete")
newTask.setValue(now, forKey: "date")
newTask.setValue(importanceValue, forKey: "importValue")
do {
try
context.save()
coreTasks.append(newTask)
print("addTask() fired!")
} catch {
print("Problem while saving")
}
}
func setupNotification(){
let currentDate = Date()
let interval = dateSelected?.timeIntervalSince(currentDate)
print(interval)
let notifcation = UNMutableNotificationContent()
notifcation.title = "Task Reminder"
notifcation.subtitle = taskTextField.text ?? "Empty"
notifcation.badge = 1
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: interval!, repeats: false)
let request = UNNotificationRequest(identifier: "taskReminder", content: notifcation, trigger: trigger)
UNUserNotificationCenter.current().add(request, withCompletionHandler: nil)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
taskTextField.endEditing(true)
}
}
func removeAllConstraintsFromView(view: UIView) { for c in view.constraints { view.removeConstraint(c) } }
extension UIView {
func removeAllConstraints() {
let superViewConstraints = superview?.constraints.filter{ $0.firstItem === self || $0.secondItem === self } ?? []
superview?.removeConstraints(superViewConstraints + constraints)
}
}
and this is my custom tableview cell
import UIKit
import CoreData
class CustomCell: UITableViewCell {
#IBOutlet var taskLabel: UILabel!
#IBOutlet var dateLabel: UILabel!
func setTask(task: NSManagedObject ){
taskLabel.text = task.value(forKey: "name") as? String
dateLabel.text = task.value(forKey: "date") as? String
}
func labelsToYellow() {
taskLabel.textColor = .white
dateLabel.textColor = .white
}
func labelsToBlack() {
taskLabel.textColor = .black
dateLabel.textColor = .black
}
Ideally When i create a new task of type nsmanaged object via the task addition. my tableview that is populate by an array of nsmanagedobject should add the task in a cell with a background color white and the task labels accordingly. I have a contextual action that marks a task complete and makes the cell background green. weirdly enough it was working at some point. Now randomly sometimes the task cell is created with a green background and sometime the labels are blank or when i scroll down or up all the labels turn green. I'd really appreciate some help.

Answer 1

I've had this issue before, because TableViewCells are re-used you need to ensure you set the background regardless of if it is default or not.
So when you are adding in the code to set the background to green, add an else statement or before the query set the cell background to white/your default color Issue with UITableViewCells Repeating Content