ios - Check for Saved IDs in Core Data database and show/hide button “Add to Fav” in Swift 3 -

i have profile view controller (vc1), , on vc1 have button says "add favourite". when tap button, able save details (id , profile name) in core data database , able see data/s in table list view inside fav view controller (vc2). now, when go vc2, can see favourites in table list , when click on 1 of record, show me details of profile.

but problem is, button have here "add favourite", need change "remove favourite" profile marked favourite.

i able understand concept, obj id needs check in database , if there match button.settitle change , required function. not able figure out correctly.

thanks time, appreciate!!!

my code saving data

 @iboutlet weak var fav_remove_fav_button_label: uibutton!   @ibaction func savefav(_ sender: any) {      var proid = saved_id     let context = (uiapplication.shared.delegate as! appdelegate).persistentcontainer.viewcontext     let task = favprofile(context: context) // link task & context     task.busname = bussinessname     task.profileid = int32(id!)!     print ("saved id is: - \(task.profileid)")     print ("saved profile name is: - \(task.busname)")     fav_remove_fav_button_label.settitle("remove favourite", for: .normal)      // save data coredata     (uiapplication.shared.delegate as! appdelegate).savecontext()      // let _ = navigationcontroller?.popviewcontroller(animated: true)      let alert = uialertcontroller(title: "alert", message: "added favourite list", preferredstyle: uialertcontrollerstyle.alert)     alert.addaction(uialertaction(title: "ok", style: uialertactionstyle.default, handler: nil))     self.present(alert, animated: true, completion: nil)   } 

my function fetch , check data

func isexist(id: int) -> bool {     var error: nserror?     var moc: nsmanagedobjectcontext!     var fetchrequest = nsfetchrequest<nsfetchrequestresult>(entityname: "favprofile")     if let results = try! moc.fetch(fetchrequest) as? [favprofile] {          if !results.isempty {             x in results {                 if x.profileid  == int32(id) {                     print("already exist")                     moc.delete(x)                 }             }         }     } else {         print(error)     }      return false } 

try ->

  func isexist(id: int) -> bool {       let context = (uiapplication.shared.delegate as! appdelegate).persistentcontainer.viewcontext      var error: error? = nil     let fetch = nsfetchrequest<nsfetchrequestresult>()     let entitydescription = nsentitydescription.entity(forentityname: "favprofile", in: context)     fetch.entity = entitydescription         as? nsentitydescription!         nsentitydescription()     fetch.predicate = nspredicate(format: "profileid == %d", id)     let fetchedobjects: [any]? = try? context.fetch(fetch)     if error != nil {         return false     }     else {         if (fetchedobjects?.count)! > 0 {               print("fetchedobjects--->found");              return true         }         else {              print("fetchedobjects--->nil");             return false         }     } }   override func viewdidload() {     super.viewdidload()   //  favbuttonlabel()   //   isexist(id: 182397)      let favcheck: bool = isexist(id:182397)     if favcheck == true {         print("favourite--->");     } }