ios - Swift 1.2 and Parse: Issue with retrieving images to populate PFQueryCollectionViewController -

i'm working on application displays images @ locations. issue following:

when user clicks on location in mapview goes empty collection view. if user pulls refresh, spinner active images not load. however, if user goes mapview , clicks on location again, images loaded in collection view. of course trying images loaded when user first goes collection view.

i think small issue, after hours of trying different various recommendations different sources cannot work properly.

any appreciated.

thank you.

here code pfquerycollectionviewcontroller:

import uikit  class photogridcollectionviewcontroller: pfquerycollectionviewcontroller {    var savedpics: [uiimage]?    func loadimages() -> pfquery {      var query = pfquery(classname: "userphoto")     query.orderbydescending("timetaken")      return query    }     override func viewdidappear(animated: bool) {    }    override func viewdidload() {     super.viewdidload()      loadimages()    }     override func didreceivememorywarning() {     super.didreceivememorywarning()     // dispose of resources can recreated.   }     /*   // mark: - navigation    // in storyboard-based application, want little preparation before navigation   override func prepareforsegue(segue: uistoryboardsegue, sender: anyobject?) {   // new view controller using segue.destinationviewcontroller.   // pass selected object new view controller.   }   */    // mark: uicollectionviewdatasource    override func numberofsectionsincollectionview(collectionview: uicollectionview) -> int {     //#warning incomplete method implementation -- return number of sections     return 1   }     override func collectionview(collectionview: uicollectionview, numberofitemsinsection section: int) -> int {     //#warning incomplete method implementation -- return number of items in section     return self.objects.count   }     override func collectionview(collectionview: uicollectionview, cellforitematindexpath indexpath: nsindexpath, object: pfobject?) -> pfcollectionviewcell? {      let cell = collectionview.dequeuereusablecellwithreuseidentifier("venuephotothumb", forindexpath: indexpath) as! photogridcollectionviewcell      if let pfobject = object {       cell.imageview.file = pfobject["imagefile"] as? pffile       cell.imageview.loadinbackground({ (img, err) -> void in         println("download complete")       })     }        return cell   } } 

edit: have updated code , bit cleaner, i'm still having exact same issue.

in previous answer used plain old uicollectionviewcontroller solve issue, after lot of digging figured out how correctly implement pfquerycollectionviewcontroller.

there must placeholder image in the pfquerycollectionviewcontroller or images not load when user first loads the pfquerycollectionviewcontroller.

here bit of code illustrate this:

import uikit import parse import parseui  class photocollectionviewcontroller: pfquerycollectionviewcontroller {  ...  var parseobject: pfobject! var placeholderview: uiview!  ...    override func viewdidload() {     super.viewdidload()      if let layout = collectionviewlayout as? uicollectionviewflowlayout {         layout.sectioninset = uiedgeinsetsmake(5.0, 10.0, 5.0, 10.0)         layout.minimuminteritemspacing = 5.0     } }  ...  // mark: pfquery override func queryforcollection() -> pfquery {     let query = super.queryforcollection()     query.wherekey("name", equalto: parseobject!)     query.orderbydescending("date")      return query }  override func collectionview(collectionview: uicollectionview,         cellforitematindexpath indexpath: nsindexpath,         object: pfobject?) -> pfcollectionviewcell? {      let cell = collectionview.dequeuereusablecellwithreuseidentifier("cell",         forindexpath: indexpath) as? customcollectionviewcell      ...              // here must have placeholder image     var initialthumbnail = uiimage(named: "thumbnail")     cell?.collectionimageview.image = initialthumbnail     if let imagefile = object?["image"] as? pffile {         cell?.collectionimageview.file = imagefile         cell?.collectionimageview.loadinbackground()     }      return cell }  ... } 

the answer quite simple, relatively new ios development took time figure out. necessity placeholder image applies both pfquerycollectionviewcontroller , pfquerytableviewcontroller.