当自定义leftBarButtonItem(s)左边缘滑动失效时

如何开启：

1.ViewController实现 UIGestureRecognizerDelegate 协议

class YourViewController: UIGestureRecognizerDelegate {

    func viewDidLoad() {
        navigationItem.setLeftBarButtonItems([...,...])   // swipe back 失效了
        self.navigationController?.interactivePopGestureRecognizer.delegate = self    // 启用 swipe back

    }

}

override func viewDidAppear(animated: Bool) {
        
        navigationController?.interactivePopGestureRecognizer.enabled = false // disable pop gesture

    }

当自定义leftBarButtonItem(s)左边缘滑动失效时

原文：http://blog.csdn.net/tounaobun/article/details/42012661