How to fix timer for drawing initiated stopwatch? - ios

Question

Hi there I am completing some research for Alzheimers - I want to be able to record the time it takes to complete a drawing. Both the time spend with apple pencil on tablet and the time spent overall to complete a drawing (time on tablet plus time in between strokes).
I have created this application so far but can't get the timer to work.
I have the drawing/scribble board down pat.
I have tried many different approaches but I am just not experienced enough in code to work out why it is not starting the timer when the apple pencil hits the tablet. The code below is for the ViewController script.
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var canvasView: CanvasView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
#IBAction func clearCanvas(_ sender: Any) { //this button will clear canvas and clear timers!
canvasView.clearCanvas()
timer.invalidate()
seconds = 0 //Here we manually enter the restarting point for the seconds, but it would be wiser to make this a variable or constant.
timeDrawing.text = "\(seconds)"
}
#IBOutlet weak var timeDrawing: UILabel! //This is one of the label used to display the time drawing (i have yet to add the label to display the time inbetween strokes)
var seconds = 0
var timer = Timer()
var isTimerRunning = false //This will be used to make sure only one timer is created at a time.
var resumeTapped = false
var touchPoint:CGPoint!
var touches:UITouch!
func runTimer() {
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: (#selector(ViewController.updateTimer)), userInfo: nil, repeats: true)
}
#objc func updateTimer() {
seconds += 1
timeDrawing.text = "\(seconds)" //This will update the label.
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
guard let touch = touches.first else { return }
let touches = touch.location(in: canvasView) // or maybe ...(in: self)
if touch.type == .pencil {
if !isTimerRunning {
runTimer()
} else {
timer.invalidate()
}
}
}
}
I was hoping when the apple pencil touched the tablet it would start the timer. And then when the pencil left the tablet it would stop one of the timers. (i have yet to add another timer for the time inbetween strokes, any help with that would be appreciated too.)

Answer 1

As #ElTomato said you're looking for touchesEnded.
You have to move timer.invalidate() from touchesBegan to touchesEnded.
Also you should change your updateTimer logic for more high accuracy.
private(set) var from: Date?
#objc func updateTimer() {
let to = Date()
let timeIntervalFrom = (from ?? to).timeIntervalSince1970
let time = to.timeIntervalSince1970 - timeIntervalFrom
timeDrawing.text = "\(round(time))" //This will update the label.
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesBegan(touches, with: event)
guard let touch = touches.first else { return }
let touches = touch.location(in: canvasView) // or maybe ...(in: self)
if touch.type == .pencil {
if !isTimerRunning {
from = Date()
runTimer()
}
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesEnded(touches, with: event)
if !isTimerRunning {
timer.invalidate()
timer = nil
from = nil
timeDrawing.text = "0"
}
}

Answer 2

Here is how it works for the code below. 1. Drag a UIView control from the object library onto the storyboard. While this control is selected, enter 'TouchView' in the class field under the identity inspector. Make an IBOutlet connection to the view controller, naming it touchView.
import UIKit
class ViewController: UIViewController, TouchViewDelegate {
// MARK: - Variables
// MARK: - IBOutlet
#IBOutlet weak var touchView: TouchView!
// MARK: - IBAction
// MARK: - Life cycle
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
/* delegate */
touchView.touchViewDelegate = self
}
// MARK: - Protocol
var startDate: Date?
func touchBegan(date: Date) {
startDate = date
}
func touchEnd(date: Date) {
if let myDate = startDate {
let components = Calendar.current.dateComponents([.second], from: myDate, to: date)
if let secs = components.second {
print(secs)
}
}
}
}
import UIKit
protocol TouchViewDelegate: class {
func touchBegan(date: Date)
func touchEnd(date: Date)
}
class TouchView: UIView {
weak var touchViewDelegate: TouchViewDelegate?
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let touch = event?.allTouches?.first
if let touchPoint = touch?.location(in: self) {
if self.bounds.contains(touchPoint) {
Swift.print("You have started a session")
touchViewDelegate?.touchBegan(date: Date())
}
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
Swift.print("You have ended the session.")
touchViewDelegate?.touchEnd(date: Date())
}
}
So when the user touches the touch view, TouchView will make a delegate call to the view controller. When the user gets his finger off off the touch view, it will make another call to the view controller. And the view controller will calculate the difference between two dates. So you don't need a timer. It's my person opinion, but you should stay away from Timer unless you have no alternatives.