swift2 - Reorder UicollectioView items using RealmSwift on drag and drop -

i'm trying reorder uicollectionviewcell images on drag , drop using realmswift database, ui not updating on drag , drop , strange behaviour, images duplicating , code this

realmmodel as

class storyalbumdm: object {      dynamic var id = 0     dynamic var type = ""     dynamic var isimage: int = 0     dynamic var textdata = ""     dynamic var imagedata: nsdata? = nil     dynamic var rowid: int = 0     dynamic var position: int = 0     dynamic var storyid: int = 0     dynamic var iscoverimage: int = 0     dynamic var imagepath = ""      let allstories = list<storyalbumdm>() } 

on drag , drop i'm doing this

func collectionview(collectionview: uicollectionview, atindexpath: nsindexpath, didmovetoindexpath toindexpath: nsindexpath) {          print("moveitematindexpath")         let fromindexpath: int = atindexpath.row         print("from", fromindexpath)          let toindexpathint: int = toindexpath.row         print("to", toindexpath)         let fromdata: storyalbumdm!         fromdata = realm.objects(storyalbumdm.self).filter("position = %d , storyid = %d", fromindexpath, self.storyid).first!         let todata: storyalbumdm!         todata = realm.objects(storyalbumdm.self).filter("position = %d , storyid = %d", toindexpath, self.storyid).first!         var tempdata = storyalbumdm()          self.performselectoronmainthread(#selector(storyviewcontroller.updatesrtoryinrealm), withobject: self.collectionview, waituntildone: true)          dispatch_async(dispatch_get_main_queue(), {             self.collectionview.performbatchupdates({                 self.collectionview.reloaddata()                 }, completion: nil)         })   }  func updatesrtoryinrealm() {          self.tempdata.type = self.todata.type         self.tempdata.isimage = self.todata.isimage         self.tempdata.textdata = self.todata.textdata         self.tempdata.rowid = self.todata.rowid         self.tempdata.imagedata = self.todata.imagedata         self.tempdata.position = self.todata.position         self.tempdata.storyid = self.todata.storyid         self.tempdata.iscoverimage = self.todata.iscoverimage         self.tempdata.imagepath = self.todata.imagepath          {             try! realm.write {                  self.todata.type = self.fromdata.type                 self.todata.isimage = self.fromdata.isimage                 self.todata.textdata = self.fromdata.textdata                 self.todata.rowid = self.fromdata.rowid                 self.todata.imagedata = self.fromdata.imagedata                 self.todata.position = self.fromdata.position                 self.todata.storyid = self.fromdata.storyid                 self.todata.iscoverimage = self.fromdata.iscoverimage                 self.todata.imagepath = self.fromdata.imagepath                  // title.id = temp.id                 self.fromdata.type = self.tempdata.type                 self.fromdata.isimage = self.tempdata.isimage                 self.fromdata.textdata = self.tempdata.textdata                 self.fromdata.rowid = self.tempdata.rowid                 self.fromdata.imagedata = self.tempdata.imagedata                 self.fromdata.position = self.tempdata.position                 self.fromdata.storyid = self.tempdata.storyid                 self.fromdata.iscoverimage = self.tempdata.iscoverimage                 self.fromdata.imagepath = self.tempdata.imagepath             }             //}         }         catch {             print("printed error : ")         } 

problem: images duplicating, not updating on ui , reorder strange behaviour, please me on this

i answered a similar question recently, i'll re-explain here. :)

easily, best , quickest way re-order realm objects inside realm file make overarching list object holds of realm objects of given type.

for example in case, make object hold allstories value created:

// model class manages ordering of story album objects class storyalbumdmlist: object {    let allstories = list<storyalbumdm>() }  // model class actual story album objects class storyalbumdm: object {    dynamic var id = 0    dynamic var type = ""    dynamic var isimage: int = 0    dynamic var textdata = ""    dynamic var imagedata: nsdata? = nil    dynamic var rowid: int = 0    dynamic var position: int = 0    dynamic var storyid: int = 0    dynamic var iscoverimage: int = 0    dynamic var imagepath = "" } 

this way, when want re-order list, need re-order them inside array.

like said in other question, 1 other way can (which not good, doesn't require realm object) add property named orderedindex, contains number indicating numerical order of these objects. when want re-order them, it's matter of re-setting these numbers.

let me know if need more clarification!