UIBarButtonItem selector not working

Question

I have a MainViewController embed in a Navigation Controller, as shown below:

And in MainViewController.swift, I added two UIBarButtonItem(left and right) progr

Answer 1

You can also just add the lazy keyword to the rightButton and leftButton class properties. That way, the UIBarButtonItem won't be instantiated (and the action selectors won't attempt to be resolved) until they are used inside the class. Doing it this way allows you to use the barButtonItems anywhere in the class (not just in the function they are declared in).

lazy var rightButton = UIBarButtonItem(title: "Right", style: .plain, target: self, action: #selector(onRightClick))
lazy var leftButton = UIBarButtonItem(title: "Left", style: .plain, target: self, action: #selector(onLeftClick))