ios - Pass request data from UIPageViewController to child views -

i have mainviewcontroller uipageviewcontroller. ther 2 views firstdataviewcontroller , seconddataviewcontroller want show.

i want execute request updates items in mainviewcontrollre , pass 2 child views.

getdata function contains data request , updates mainviewcontroller's items

extension mainviewcontroller {     func getdata() {         getbasicdata() { [weak self] (basicmodel) in             guard let strongself = self else { return }             strongself.getexperiencedata() { [weak self] (experiencemodel) in                 guard let strongself = self else { return }                  let items = requestitems(basicdata: basicmodel,                                          experiencedata: experiencemodel)                  strongself.updateitems(items: items)             }         }     } } 

mainviewcontroller:

class mainviewcontroller: uipageviewcontroller {      var items: requestitems      let firstdataviewcontroller: firstdataviewcontroller     let seconddataviewcontroller: seconddataviewcontroller      let basicdatamanager: apimanagerprotocol     let experiencedatamanager: apimanagerprotocol      private(set) lazy var orderedviewcontrollers: [uiviewcontroller] = {         return [self.firstdataviewcontroller, self.seconddataviewcontroller]     }()      convenience init() {         self.init(with: requestitems())     }      init(with items: requestitems) {          self.items = items          let apimanager = apimanager()         basicdatamanager = apimanager.createbasicdatamanager()         experiencedatamanager = apimanager.createexperiencedatamanager()          self.firstdataviewcontroller = firstdataviewcontroller(with: items)         self.seconddataviewcontroller = seconddataviewcontroller(with: items)          super.init(transitionstyle: .scroll, navigationorientation: .horizontal, options: nil)          self.edgesforextendedlayout = []     }      func updateitems(items: requestitems) {         self.items = items     } } 

how use getdata() function update mainviewcontroller items first , pass data child views? or maybe there better option this?

it's not solution. "getdata" method needs time execute should:

• execute "getdata" before load mainviewcontroller, pass "request items" , update yours views.

but assume mainviewcontroller first controller in application should:

1. add completion block "getdata" method:

   func getdata(_ completion: [requestitems] -> ()) {      getbasicdata() { [weak self] (basicmodel) in          guard let strongself = self else { return }          strongself.getexperiencedata() { [weak self] (experiencemodel) in              guard let strongself = self else { return }              let items = requestitems(basicdata: basicmodel,                                  experiencedata: experiencemodel)              completion(items)         }     } } 

2. add "updateitems" method yours view controllers (instead of passing in init method)

3. call "getdata" method completion handler outside of mainviewcontroller init

   init(with items: requestitems) {     ...     self.items = items      self.firstdataviewcontroller = firstdataviewcontroller()     self.seconddataviewcontroller = seconddataviewcontroller()     ... }  func viewdidload() {     super.viewdidload()      getbasicdata { [weak self] (items) in          guard let strongself = self else { return }           strongself.updateitems(items)         strongself.firstdataviewcontroller.updateitems(with: items)         strongself.seconddataviewcontroller.updateitems(with: items)     } }  func updateitems(items: requestitems) {     self.items = items }