ios - How to call timer one time in application using swift? -

hi developing app using swift 2 in app updating current location every x minutes using nstimer able update location , works fine.in app(first view controller) when user logged in , moves second view controller in(second view controller) wrote function updating location using nstimer works fine when user moves third view controller , return second view controller again start updating location cant able stop timer twice invalidate timer 1 time other 1 keep on updating location after users logged out.so please me out solve problem.

my second view controller:

class secondviewcontroller:uiviewcontroller{ 

in view did load method:

  var appdelegate:appdelegate = uiapplication.sharedapplication().delegate as! appdelegate              appdelegate.timer = nstimer.scheduledtimerwithtimeinterval(10.0, target: self, selector: #selector(timetomoveon), userinfo: nil, repeats: true)   //i declared var timer:nstimer! in appdelegate.swift , performed function using nstimer 

my third view controller:

i created button action logout code is:

  var appdelegate:appdelegate = (uiapplication.sharedapplication().delegate as?             appdelegate)!          appdelegate.timer.invalidate() 

thanks in advance

hi thank support found answer question

i kept timer.invalidate() in 2 different methods according project

i suggest this:

this singleton wrap location.

sorry, swift3 have this:

class lm: nsobject, cllocationmanagerdelegate {     //mark: public variable      var lat = 0.0     var lon = 0.0     var cast = "location_cast"     public static let : lm = {         let instance = lm()         return instance     }()      //mark: local variable      fileprivate var locationmanager: cllocationmanager?      //mark: init     public override init() {         super.init()         locationmanager = cllocationmanager()         locationmanager?.delegate = self     }     internal func start() {         locationmanager?.startupdatinglocation()     }     internal func stop() {         locationmanager?.startupdatinglocation()     }     func locationmanager(_ manager: cllocationmanager, didfailwitherror error: error) {         //code         print("\(error)")     }     func locationmanager(_ manager: cllocationmanager, didupdatelocations locations: [cllocation]) {         //code //        print("\(locations)")         if let loc = locations.last { //simple store retrieve later             lat = loc.coordinate.latitude             lon = loc.coordinate.longitude                   //cast here notification                 notificationcenter.default.post(name: nsnotification.name(rawvalue: cast), object: ["lat": lat, "lon": lon])         }      }     func locationmanager(_ manager: cllocationmanager, didchangeauthorization status: clauthorizationstatus) {         switch status {         case .notdetermined:             manager.requestalwaysauthorization()             break         case .authorizedwheninuse:             manager.startupdatinglocation()             break         case .authorizedalways:             manager.startupdatinglocation()             break         case .restricted:             // restricted e.g. parental controls. user can't enable location services             break         case .denied:             // user denied app access location services, can grant access settings.app             break         }     } } 

to start , stop locationmanager use this:

@uiapplicationmain class appdelegate: uiresponder, uiapplicationdelegate { //... var window: uiwindow?      func application(_ application: uiapplication, didfinishlaunchingwithoptions launchoptions: [uiapplicationlaunchoptionskey : any]? = nil) -> bool { // override point customization after application launch.         _  = lm.i         return true     }  func applicationwillresignactive(_ application: uiapplication) {         // sent when application move active inactive state. can occur types of temporary interruptions (such incoming phone call or sms message) or when user quits application , begins transition background state.         lm.i.stop()     }   func applicationdidbecomeactive(_ application: uiapplication) {         // restart tasks paused (or not yet started) while application inactive. if application in background, optionally refresh user interface.          lm.i.start()     } } 

you can add inside appdelegate custom timer casting variables each 1 second

let casttoviewcontroller = "casttoviewcontroller"  notificationcenter.default.post(name: nsnotification.name(rawvalue: casttoviewcontroller), object: ["lat": lm.i.lat, "lon": lm.i.lon]) 

or simple

 let casttoviewcontroller_ping = "casttoviewcontroller_ping" notificationcenter.default.post(name: nsnotification.name(rawvalue: casttoviewcontroller), object: nil) 

to catch new data casted values use this:

https://stackoverflow.com/a/38615219/1979882

if not manage .start() , .stop() ios kick background timer application each in several minutes if press 'home' button.