ios - Creating App to create circles when users taps view -

i ask if figure out what's wrong code, can't seem create circle when there touch event.

override func viewdidload() {     super.viewdidload()     self.view.backgroundcolor = uicolor.lightgray     // additional setup after loading view, typically nib.  }  func touchesbegan(touches: set<nsobject>, withevent event: uievent) {     if let touch = touches as? set<uitouch> {          let circlecenter = touch.first!.location(in: view)          let circlewidth = cgfloat(25)         let circleheight = circlewidth          let circleview = circleview(frame: cgrect(x: circlecenter.x, y: circlecenter.y, width: circlewidth, height: circleheight))         view.addsubview(circleview)     } }  override func didreceivememorywarning() {     super.didreceivememorywarning()     // dispose of resources can recreated. } 

if need code subview circleview:

class circleview: uiview {  override init(frame: cgrect) {     super.init(frame: frame)     self.backgroundcolor = uicolor.clear }  required init(coder adecoder: nscoder) {     fatalerror("init(coder:) has not been implemented") }  func draw(rect: cgrect) {      var context = uigraphicsgetcurrentcontext();      context!.setlinewidth(5.0)      uicolor.red.set()      let center = cgpoint(x: round(frame.size.width)/(2), y: round(frame.size.height)/2)     let radius = (round(frame.size.width) - 10)/(2)      context!.addarc(center:center, radius:radius, startangle:0, endangle:cgfloat(double.pi) * 2, clockwise:true)      context!.strokepath();      } 

two of functions incorrect (as of in swift 3). change

func touchesbegan(touches: set<nsobject>, withevent event: uievent) 

to

override func touchesbegan(_ touches: set<uitouch>, event: uievent?) 

and change

func draw(rect: cgrect) 

to

override func draw(_ rect: cgrect)