ios - Uploading music through parse return "fatal error: Array index out of range" -

import uikit import parse import bolts import avfoundation import avkit  public var audioplayer = avplayer() public var selectedsongnumber = int()  class tableviewcontroller: uitableviewcontroller, avaudioplayerdelegate{      var idarray = [string]()     var namearray = [string]()      override func viewdidload() {         super.viewdidload()         // additional setup after loading view, typically nib.          var objectidquery = pfquery (classname: "songs")         objectidquery.findobjectsinbackgroundwithblock({            (objectsarray: [anyobject]?, error: nserror?) -> void in            var objectids = objectsarray as! [pfobject]            nslog("\(objectids)")            in 0...objectids.count-1{                self.idarray.append(objectids[i].valueforkey("objectid") as! string)                self.namearray.append(objectids[i].valueforkey("songname") as! string)                self.tableview.reloaddata()             }        })      }      func grabsong(){          var songquery = pfquery(classname: "songs")          songquery.getobjectinbackgroundwithid(idarray[selectedsongnumber], block:  {          (object : pfobject?, error : nserror?) -> void in                    if let audiofileurltemp = object?.objectforkey("songfile")?.url{                     audioplayer = avplayer(url: nsurl(string: audiofileurltemp!))                    audioplayer.play()            }         })     }       override func tableview(tableview: uitableview, numberofrowsinsection section: int) -> int {         return idarray.count     }      override func tableview(tableview: uitableview, cellforrowatindexpath indexpath: nsindexpath) -> uitableviewcell {         var cell = tableview.dequeuereusablecellwithidentifier("cell") as! uitableviewcell         cell.textlabel?.text = namearray[indexpath.row]         return cell     }       override func tableview(tableview: uitableview, didselectrowatindexpath indexpath: nsindexpath) {         selectedsongnumber = indexpath.row         grabsong()     } }