ios - How to imitate stock back button -

this question has answer here:

• setting action button in navigation controller 27 answers

i want add action standard back-button, won't work found below link:

add-target-to-stock-back-button-in-navigationbar

so created custom button action.

uibarbuttonitem(title: "❮ back", style: .bordered, target: self, action: "back:") 

but how can set standard left wing title?

the character '❮' way smaller standard button. use standard button throughout app, , want keep optic.

if want "add" functionality button can use uinavigationcontrollerdelegate.

when press button, navigation controller call navigationcontroller(willshowviewcontroller:) can use whatever want do. example shown below:

using uinavigationcontrollerdelegate:

class viewcontroller: uiviewcontroller, uinavigationcontrollerdelegate {      override func viewdidload() {         super.viewdidload()          navigationcontroller?.delegate = self     }      func navigationcontroller(navigationcontroller: uinavigationcontroller, willshowviewcontroller viewcontroller: uiviewcontroller, animated: bool) {         // add whatever want here     } }