swift - Button to upload integer to Firebase database IOS -

when button pressed, need save rating of item in database. while slider works , variable 'currentvalue' works, have unable rating submitted database though crashes app. if i've made simple mistake, let me know.

import uikit import fbsdkcorekit import fbsdkloginkit import firebasedatabase  class secondviewcontroller: uiviewcontroller {  var ref:firdatabasereference!  @iboutlet weak var sliderlabel: uilabel!   @iboutlet weak var verticalslider: uislider!         {             didset{                 verticalslider.transform = cgaffinetransform(rotationangle: cgfloat(-m_pi_2))              }     }  @ibaction func verticalsliderchanged(_ sender: uislider) {          var currentvalue = int(sender.value);          sliderlabel?.text = "\(currentvalue)"  }   @ibaction func checkmarkbuttonpressed(_ sender: any) {       let img:uiimageview = uiimageview(frame: cgrect(x: 30, y: 180, width: 250, height: 320))      let randomimage = arc4random()      if (randomimage % 4 == 0) {         img.image = uiimage(named: "hero.jpg")     } else if (randomimage % 3 == 1) {         img.image = uiimage(named: "hillary.jpg")     } else {         img.image = uiimage(named: "thistimeisdifferent.png")      **self.ref.child(uuid).child("book info").child("book title").child("slider value").setvalue(currentvalue)**      }  } 

while not able give exact answer fix without seeing more of project, can suggest few things.

first, make sure of @iboutlets , @ibactions connected. sure cause crash if these objects , actions not connected. troubleshoot this, comment out code , set breakpoint on actions , see if able interact outlets , actions.

second, validate execution of code make sure working safe data. example,

@ibaction func verticalsliderchanged(_ sender: uislider) {     // allow safer way interact data     if let currentvalue = sender.value as? int {         sliderlabel?.text = "\(currentvalue)"     } }  @ibaction func checkmarkbuttonpressed(_ sender: any) {       let img:uiimageview = uiimageview(frame: cgrect(x: 30, y: 180, width: 250, height: 320))     self.view.addsubview(img)      guard img != nil else {         return     }      let randomimage = arc4random()      if (randomimage % 4 == 0) {         img.image = uiimage(named: "hero.jpg")     } else if (randomimage % 3 == 1) {         img.image = uiimage(named: "hillary.jpg")     } else {         img.image = uiimage(named: "thistimeisdifferent.png")          guard let currentval = currentvalue,                currentval.characters.count > 0 else {             return         }         self.ref.child(uuid).child("book info").child("book title").child("slider value").setvalue(currentval)      } 

validating data working each step of way should allow determine if issue data inserting firebase, outlets, or application logic.

hope helps.