NavigationDemo

展示三种popViewController的效果，例如淘宝、京东的“整体返回”效果

效果图：

实现思路：

1. 创建Pan手势识别器

2. 实现手势的相应事件

3. 创建截图所需的backgroundView和blackMask作为遮罩，以及存放截图所需数组的类

4. 在push之前截图并保存

5. 重写常用的pop方法，在pop之前删除相应的截图

override func popViewController(animated: Bool) -> UIViewController?
override func popToViewController(_ viewController: UIViewController, animated: Bool) -> [UIViewController]?
override func popToRootViewController(animated: Bool) -> [UIViewController]?

到此处可以实现手势整体返回的效果，要实现点击返回按钮也能整体返回，需要自定义返回动画。实现协议UIViewControllerAnimatedTransitioning。

6. 让navigationController遵守UINavigationControllerDelegate并实现以下方法，在方法中可以根据operation判断需要自定义的类型(pop/push)

 func navigationController(_ navigationController: UINavigationController, 
 animationControllerFor operation: UINavigationControllerOperation, 
 from fromVC: UIViewController,
  to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning?

7. 使用一个类实现UIViewControllerAnimatedTransitioning协议

func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval

//定义动画
func animateTransition(using transitionContext: UIViewControllerContextTransitioning)

K UINavigationController 1.0.1

K UINavigationController 1.0.1

K UINavigationController 1.0.1

NavigationDemo