蛊毒传说
				您可以这样实现UINavigationControllerDelegate:较早的斯威夫特func navigationController(navigationController: UINavigationController, willShowViewController viewController: UIViewController, animated: Bool) {    let item = UIBarButtonItem(title: " ", style: .Plain, target: nil, action: nil)    viewController.navigationItem.backBarButtonItem = item}斯威夫特4.xclass MyNavigationController: UINavigationController, UINavigationControllerDelegate {    override func viewDidLoad() {        super.viewDidLoad()        self.delegate = self    }    func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {        let item = UIBarButtonItem(title: " ", style: .plain, target: nil, action: nil)        viewController.navigationItem.backBarButtonItem = item    }}backBarButtonItem是nil默认设置,它会影响下一个推送的控制器,因此您只需为所有控制器进行设置