Uitextview Add placeholder (Swift)

uitextview Add placeholder (Swift)by Wusheying
add Uilabel and initialize
Public  LetPlaceholderlabel:UILabel = UILabel()
@IBInspectable Publicvarplaceholder:String ="" {
        Didset {
            Placeholderlabel.text =placeholder
        }
    }
    
@IBInspectable PublicvarPlaceholdercolor:Uicolor =Uicolor(red:0.0, Green:0.0, Blue:0.0980392, Alpha:0.22) {
        Didset {
            Placeholderlabel.TextColor =Placeholdercolor
        }
    }
Override Publicvarfont:Uifont! {
        Didset {
            Placeholderlabel.Font =Font
        }
    }
    
Override Publicvartextalignment:nstextalignment {
        Didset {
            Placeholderlabel.TextAlignment =TextAlignment
        }
    }
Addsubview Addup
Override Init(frame:CGRect, TextContainer:Nstextcontainer?) {
        Super.Init(Frame:frame, Textcontainer:textcontainer)
        Commoninit()
    }
    
    Required PublicInit(coder Adecoder:Nscoder) {
        Super.Init(Coder:adecoder)
        Commoninit()
    }
    
    funcCommoninit () {
        Nsnotificationcenter.Defaultcenter().Addobserver( Self,
selector:"Textdidchange",
Name:uitextviewtextdidchangenotification,
object:Nil)
        
        Placeholderlabel.Font =Font
        Placeholderlabel.TextColor =Placeholdercolor
        Placeholderlabel.TextAlignment =TextAlignment
        Placeholderlabel.text =placeholder
        Placeholderlabel.NumberOfLines =0
        Placeholderlabel.BackgroundColor =Uicolor.Clearcolor()
        Placeholderlabel.settranslatesautoresizingmaskintoconstraints(false)
        Addsubview(Placeholderlabel)
    }

Enter the event that the text disappears
Override PublicvarText:String! {
        Didset {
            Textdidchange()
        }
    }

funcTextdidchange () {
        Placeholderlabel.Hidden = !text.IsEmpty
    }

Uitextview Add placeholder (Swift)