当前控制器只需要实现2个代理方法
- (BOOL)navigationControllerShouldPop:(UINavigationController *)navigatonController;
- (BOOL)navigationControllerShouldStarInteractivePopGestureRecognizer:(UINavigationController *)navigatonController;在.h文件中定义了一个宏 MergeGestureToBackMethod ,控制点按钮返回和手势返回是否执行同一个代理方法,默认是YES,即不用实现
- (BOOL)navigationControllerShouldStarInteractivePopGestureRecognizer:(UINavigationController *)navigatonController;协议。