ios - use activity indicator in many VC without duplicating code swift -

i have 2 viewcontrollers (a , b) in swift ios. both , b loads data internet (separately). want display activityindicator while loading. know can bad way declaring once in each vc follows

viewcontroller a

var activityindicator: uiactivityindicatorview = uiactivityindicatorview()  func activityindicatorbegin() {     activityindicator = uiactivityindicatorview(frame: cgrectmake(0,0,50,50))     activityindicator.center = self.view.center     activityindicator.hideswhenstopped = true     activityindicator.activityindicatorviewstyle = uiactivityindicatorviewstyle.gray     view.addsubview(activityindicator)     activityindicator.startanimating()     disableuserinteraction()      greyview = uiview()     greyview.frame = cgrectmake(0, 0, self.view.bounds.width, self.view.bounds.height)     greyview.backgroundcolor = uicolor.blackcolor()     greyview.alpha = 0.5     self.view.addsubview(greyview) }  func activityindicatorend() {     self.activityindicator.stopanimating()     enableuserinteraction()     self.greyview.removefromsuperview() } 

and exact same viewcontroller b , call activityindicatorbegin , activityindicatorend functions declared in b view controller. however, want make code cleaner. how done? trying make code cleaner these days.

thanks,

--update--

i imageing following code work. doesnt because cant declare variables in extensions

    var activityindicator: uiactivityindicatorview = uiactivityindicatorview()  extension uiviewcontroller {     func activityindicatorbegin() {     activityindicator = uiactivityindicatorview(frame: cgrectmake(0,0,50,50))     activityindicator.center = self.view.center     activityindicator.hideswhenstopped = true     activityindicator.activityindicatorviewstyle = uiactivityindicatorviewstyle.gray     view.addsubview(activityindicator)     activityindicator.startanimating()     disableuserinteraction()      greyview = uiview()     greyview.frame = cgrectmake(0, 0, self.view.bounds.width, self.view.bounds.height)     greyview.backgroundcolor = uicolor.blackcolor()     greyview.alpha = 0.5     self.view.addsubview(greyview) }  func activityindicatorend() {     self.activityindicator.stopanimating()     enableuserinteraction()     self.greyview.removefromsuperview()     } } 

create 1 baseviewcontroller , add these 2 method , declare activityindicator object inside baseviewcontroller. make baseviewcontroller parent class of viewcontroller. after if want add indicator call this

1) create baseviewcontroller

class baseviewcontroller: uiviewcontroller {     var activityindicator: uiactivityindicatorview = uiactivityindicatorview()      override func viewdidload() {         super.viewdidload()     }      override func didreceivememorywarning() {         super.didreceivememorywarning()         // dispose of resources can recreated.     }      func activityindicatorbegin() {         activityindicator = uiactivityindicatorview(frame: cgrectmake(0,0,50,50))         activityindicator.center = self.view.center         activityindicator.hideswhenstopped = true         activityindicator.activityindicatorviewstyle = uiactivityindicatorviewstyle.gray         view.addsubview(activityindicator)         activityindicator.startanimating()         disableuserinteraction()          greyview = uiview()         greyview.frame = cgrectmake(0, 0, self.view.bounds.width, self.view.bounds.height)         greyview.backgroundcolor = uicolor.blackcolor()         greyview.alpha = 0.5         self.view.addsubview(greyview)     }      func activityindicatorend() {         self.activityindicator.stopanimating()         enableuserinteraction()         self.greyview.removefromsuperview()     } } 

2) assign baseviewcontroller parent of viewcontroller this

class viewcontroller1: baseviewcontroller {      override func viewdidload() {         super.viewdidload()         //now if want add activityindicator call         self.activityindicatorbegin()         //or if want remove activityindicator          self.activityindicatorend()     }      override func didreceivememorywarning() {         super.didreceivememorywarning()         // dispose of resources can recreated.     }  }