swift - Why is the slider not updating the label when I make the slider programmatically? -

i made slider , label programmatically. wanted label display value of slider, label displays value assigned.

code:

var num: cgfloat = 9  override func viewdidload() {     let label = uilabel(frame: cgrectmake(0, 0, 60, 40))     label.text = "\(num)"     self.view.addsubview(label)      let slider = uislider(frame:cgrectmake(0, 0, 60, 30))      slider.value = float(num)     slider.addtarget(self, action: "changedslidervalue:", forcontrolevents: .valuechanged)     self.view.addsubview(slider) }  func changedslidervalue(sender: uislider!){     num = cgfloat(sender.value)     label.text = "\(num)" } 

when did print(label.text!), showed me label.text changing changed slider value. then, why doesn't label change on view controller?

you have create ibaction slider shown in below code:

@ibaction func slidervaluechanged(sender: uislider) {      num = sender.value     label.text = "\(num)" } 

for more info refer this tutorial.

update:

below complete working code:

import uikit  class viewcontroller: uiviewcontroller {      var num: cgfloat = 9     let label = uilabel(frame: cgrectmake(0, 0, 60, 40))      override func viewdidload() {         super.viewdidload()          label.text = "\(num)"         self.view.addsubview(label)          let slider = uislider(frame:cgrectmake(0, 0, 60, 30))         slider.value = float(num)         slider.addtarget(self, action: "changedslidervalue:", forcontrolevents: .valuechanged)         self.view.addsubview(slider)     }      func changedslidervalue(sender: uislider!){         num = cgfloat(sender.value)         label.text = "\(num)"     } }