ios - Swift: Cannot get correct height of header cell's label after sizetofit -

i have add sizetofit() uilabel, cannot correct height cannot show text. show "academic, administrative, teaching and"

testing target: iphone 6

coding:

class eventsviewcontroller: uitableviewcontroller {      var headername: array<string> = ["academic, administrative, teaching , learning support units"]     override func viewdidload() {        self.tableview = uitableview(frame: self.tableview.frame, style: .grouped)        self.view.backgroundcolor = uicolor(white: 0.9, alpha: 1.0)        self.tableview.estimatedrowheight = 102     }    override func tableview(tableview: uitableview, viewforheaderinsection section: int) -> uiview? {       var headercell = tableview.dequeuereusablecellwithidentifier("eventsheadercell") as! uitableviewcell!      if headercell == nil {         headercell = uitableviewcell(style: uitableviewcellstyle.default, reuseidentifier: "eventsheadercell")     }     headercell!.backgroundcolor = uicolor(white: 0.9, alpha: 1.0)     headercell!.textlabel?.text = headername[section]     headercell!.textlabel?.numberoflines = 0     headercell!.textlabel?.linebreakmode = .bywordwrapping     headercell!.textlabel?.sizetofit()     headercell!.userinteractionenabled = false;     headercell!.sizetofit()     return headercell!    }     override func numberofsectionsintableview(tableview: uitableview) -> int {         return headername.count     }      override func tableview(tableview: uitableview, heightforheaderinsection section: int) -> cgfloat {             var headerlabel:uilabel = uilabel()             headerlabel.text = headername[section]             headerlabel.numberoflines = 0             headerlabel.linebreakmode = .bywordwrapping             headerlabel.sizetofit()              return headerlabel.frame.size.height          }  } 

the problem non-break long text cause getting non-break uilabel height after sizetofit(). but, shows text has been break in iphone 6 ios 8.

override func tableview(tableview: uitableview, heightforheaderinsection section: int) -> cgfloat {     var headerlabel:uilabel = uilabel()     var newline: cgfloat = 1     headerlabel.text = headername[section]     headerlabel.numberoflines = 0     headerlabel.linebreakmode = .bywordwrapping     headerlabel.sizetofit()      if self.view.frame.width <= headerlabel.frame.width     {         newline = ceil(headerlabel.frame.width/self.view.frame.width)     }      let tblheaderheight = (headerlabel.frame.size.height * newline) + ios7_8info.geteventheadercellspacingheight() cgfloat     return tblheaderheight }