1.继承链：UIviewcontroller：uiresponder：NSObject
2.如果你想使用一些动画转换，可以遵守 UINavigationControllerDelegate
3.创建导航控制器：
(1)- (instancetype)initWithRootViewController:(UIViewController *)rootViewController :使用系统默认的导航栏和工具栏，通过一个根视图创建导航控制器
(2)- (instancetype)initWithNavigationBarClass:(Class)navigationBarClass toolbarClass:(Class)toolbarClass :通过一个自定义的导航栏和工具栏创建导航控制器
4.访问导航栈的item
(1)@property(nonatomic, readonly, strong) UIViewController *topViewController :返回栈顶的controller
(2)@property(nonatomic, readonly, strong) UIViewController *visibleViewController :返回显示的controller
(3)@property(nonatomic, copy) NSArray <__kindof UIViewController *> *viewControllers :返回堆栈中所有的controller
(4)- (void)setViewControllers:(NSArray<UIViewController *> *)viewControllers animated:(BOOL)animated :设置管理的视图控制器
5.推出和压进栈item
(1)- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated :压入新的视图控制器
(2)- (UIViewController *)popViewControllerAnimated:(BOOL)animated :弹出一个视图控制器 返回的是栈顶的controller
(3)- (NSArray<__kindofUIViewController *> *)popToRootViewControllerAnimated:(BOOL)animated :rootviewcontroller将会成为栈顶视图,返回所有的视图
(4)- (NSArray<__kindofUIViewController *> *)popToViewController:(UIViewController *)viewController animated:(BOOL)animated ：弹出到某个视图控制器 返回所有弹出的controller
(5)@property(nonatomic, readonly) UIGestureRecognizer *interactivePopGestureRecognizer :iOS7之后，在导航中右划会进行pop操作，设置这个的enable可以控制设置手势是否失效
6.配置导航条
(1)@property(nonatomic, readonly) UINavigationBar *navigationBar :导航栏对象，只读属性
(2)- (void)setNavigationBarHidden:(BOOL)hidden animated:(BOOL)animated :设置隐藏导航栏
7.配置自定义的工具栏
(1)@property(nonatomic, readonly) UIToolbar *toolbar :获取工具栏对象
(2)- (void)setToolbarHidden:(BOOL)hidden animated:(BOOL)animated :隐藏工具栏
(3)@property(nonatomic, getter=isToolbarHidden) BOOL toolbarHidden :隐藏工具栏
8.隐藏导航条
(1)@property(nonatomic, readwrite, assign) BOOL hidesBarsOnTap :敲击屏幕可以隐藏与显示导航栏
(2)@property(nonatomic, readwrite, assign) BOOL hidesBarsOnSwipe :屏幕滑动的时候隐藏导航栏，常用于tableView,上滑隐藏导航栏，下滑显示，带动画效果
(3)@property(nonatomic, readwrite, assign) BOOL hidesBarsWhenVerticallyCompact :横屏的时候隐藏导航栏
(4)@property(nonatomic, readwrite, assign) BOOL hidesBarsWhenKeyboardAppears :当键盘出现的时候隐藏导航条
(5)@property(nonatomic, getter=isNavigationBarHidden) BOOL navigationBarHidden ：隐藏导航条
(6)@property(nonatomic, readonly, assign) UITapGestureRecognizer *barHideOnTapGestureRecognizer :获取敲击屏幕的手势
(7)@property(nonatomic, readonly, strong) UIPanGestureRecognizer *barHideOnSwipeGestureRecognizer :获取滑动屏幕的手势
(8)@property(nonatomic, weak) id< UINavigationControllerDelegate > delegate :设置委托
9.显示viewcontroller的动作方法
(1)- (void)showViewController:(UIViewController *)vc sender:(id)sender :这个方法是为了iOS方法的命名统一，在导航中，其作用和push一样