ios - set button image as setSelected -

i want change image of button on click.i have question in application , answer given app user in yes , no format .for have taken 2 button checkbox empty image .i want change image of button in checkbox_fill if clicked , button set empty checkbox image.how check if button have selected or not ?.my code below.

@ibaction func btnpainclicked(sender: anyobject) {       var selected   : uiimage = uiimage(named:"checkbox_fill.png")!     var deselected : uiimage = uiimage(named: "checkbox.png")!     if (sender.tag == 1){          if(!sender.setselected){              btnno.setimage(deselected, forstate:.normal)             btnyes.setimage(selected, forstate:.normal)          }else if(!sender.setselected){              btnyes.setimage(deselected, forstate: .normal)             btnno.setimage(selected, forstate: .normal)         }      }    } 

i want 1 button selected , empty checkbox image.

i have simpler solution this. in viewdidload, add following code:

var selected   : uiimage = uiimage(named:"checkbox_fill.png")! var deselected : uiimage = uiimage(named: "checkbox.png")! btnno.setimage(deselected, forstate:.normal) btnno.setimage(selected, forstate:.selected) btnyes.setimage(deselected, forstate:.normal) btnyes.setimage(selected, forstate:.selected) 

and in func, btnpainclicked

replace code :

 sender.selected=true    // sender.selected = yes     if(sender == btnyes) {         btnno.selected = false     }     else {         btnyes.selected = false     } 

try this.. work radio button want... let me know :)