timer - I need a reliable StopWatch in Swift 3 -


i need reliable stopwatch in swift 3. came based on example found on ...

import foundation  class stopwatch {     public private(set) var seconds:double = 0     public var milliseconds: double { return seconds * 1000 }          private weak var timer:timer?     private var starttime:double = 0     public private(set) var started = false            public func start() {         if started { return }         started = true         starttime = date().timeintervalsincereferencedate         timer = timer.scheduledtimer(withtimeinterval: 0.05, repeats: true) {             timer in             if !self.started { return }             self.seconds = date().timeintervalsincereferencedate - self.starttime             print("seconds: \(self.seconds)")         }         print("started")     }      public func stop() {         if !started { return }         timer?.invalidate()         started = false         print("stopped")     } }

but doesn't seem work reliably. fetching seconds staying @ 0 or in other cases when accessing seconds don't start 0. wrong code?

it's threading issue. if ui involved have make sure ui related code runs on main thread.

the variable started redundant. checking timer nil same.

this code adds dispatchqueue.main block. put code update ui block

class stopwatch {     public private(set) var seconds:double = 0     public var milliseconds: double { return seconds * 1000 }     private weak var timer : timer?     private var starttime : double = 0     private var timerisrunning : bool { return timer != nil }      public func start() {         if timerisrunning { return }         starttime = date().timeintervalsincereferencedate         timer = timer.scheduledtimer(withtimeinterval: 0.05, repeats: true) { timer in             self.seconds = date().timeintervalsincereferencedate - self.starttime             print("seconds: \(self.seconds)")             dispatchqueue.main.async {                 // on main thread             }         }         print("started")     }      public func stop() {         if !timerisrunning { return }         timer!.invalidate()         timer = nil         print("stopped")     } }

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