swift - takePicture() with cameraOverlayView -

i'm using cameraoverlayview create custom camera. however, i'm not sure how make button shoot photo. apple docs takepicture() function use. not compile:

neither attempt works:

let shootpicture = uibarbuttonitem(barbuttonsystemitem: uibarbuttonsystemitem.camera, target: self, action: takepicture())  let shootpicture = uibarbuttonitem(barbuttonsystemitem: uibarbuttonsystemitem.camera, target: self, { action -> void in             takepicture()         }) 

updated attempt:

let shootpicture = uibarbuttonitem(barbuttonsystemitem: uibarbuttonsystemitem.camera,  style: uibarbuttonitemstyle.plain, target: self, action: "takepicture")  // separate function func takepicture() {         imagepicker.takepicture() } 

still getting syntax error: missing argument parameter 'landscapeimagephone' in call

but when add landscapeimagephone: uibarbuttonsystemitem.camera, "extra argument 'landscapeimagephone' in call"

for else stuck on this:

set bar item:

let shootpicture = uibarbuttonitem(barbuttonsystemitem: uibarbuttonsystemitem.camera,  target: self, action: "takepicture") 

create function

func takepicture() {     imagepicker.takepicture() }