swift - I need two timers working in the same View Controller ios -

i have problem 2 timers running in same view controller. need 1 of them launch when other invalidated , go on after start button first tapped again. tried creating 2 variables , builds successfully, behavior erratic. right approach? thanks

@ibaction func start(_ sender: anyobject) {     timer2.invalidate()     timer = timer.scheduledtimer(timeinterval: 1.0, target: self, selector: #selector(viewcontroller.update), userinfo: nil, repeats: true) }     @ibaction func pausetimer(_ sender: anyobject) {      timer.invalidate()      timer2 = timer.scheduledtimer(timeinterval: 1.0, target: self, selector: selector(("increasetimer")), userinfo: nil, repeats: true)    } 

so need sort of "flip flop" timer effect?

hav thought replacing var timerhasfinishedrunning: bool = false checking invalidation?

e.g.

// when invalidate, rather timer1.invalidate() timer1 = nil  // goes timer2 timer2.invalidate() timer2 = nil 

that way, can have timer checking done view computed properties:

var timer1hasfinishedrunning: bool {     return self.timer1 == nil }  var timer1hasfinishedrunning: bool {     return self.timer2 == nil } 

also mention behave "erratically", elaborate? timer interval 1 second, if erratic happens, "within 1 second" it's because of long interval. e.g. checking of each done once per second, take long 1.999999 seconds notice timer invalidated.

personally, i'd have interval @ 0.1 rather 1.0 greater accuracy.