第十三篇、Swift_Nav自定义返回按钮后或者隐藏导航栏，Pop返回手势失效的解决方法 Pop全局返回添加的方法

边缘的pop返回手势：

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.purple
        // 保留Pop手势
        navigationController?.interactivePopGestureRecognizer?.delegate = self
        navigationController?.interactivePopGestureRecognizer?.isEnabled = true
    }

这些代码主要实在UINavigationController上添加

Swift全屏pop返回手势：

class CustomNavigationController: UINavigationController {
    override func viewDidLoad() {
        super.viewDidLoad()
        // 1.取出手势&view
        guard let gesture = interactivePopGestureRecognizer else { return }
        gesture.isEnabled = false
        let gestureView = gesture.view
        // 2.获取所有的target
        let target = (gesture.value(forKey: "_targets") as? [NSObject])?.first
        guard let transition = target?.value(forKey: "_target") else { return }
        let action = Selector(("handleNavigationTransition:"))
        // 3.创建新的手势
        let popGes = UIPanGestureRecognizer()
        popGes.maximumNumberOfTouches =
        gestureView?.addGestureRecognizer(popGes)
        popGes.addTarget(transition, action: action)
    }
    override func pushViewController(_ viewController: UIViewController, animated: Bool) {
        viewController.hidesBottomBarWhenPushed = true
        super.pushViewController(viewController, animated: animated)
    }
}

OC POP手势返回：

- (void)viewDidLoad {
    [super viewDidLoad];

    id target = self.interactivePopGestureRecognizer.delegate;
    UIPanGestureRecognizer * pan = [[UIPanGestureRecognizer alloc]initWithTarget:target action:@selector(handleNavigationTransition:)];
    pan.delegate = self;
    [self.view addGestureRecognizer:pan];
    [self.interactivePopGestureRecognizer setEnabled:NO];
}

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
    return self.childViewControllers.count ==  ? NO : YES;
}