首先是navigationcontroller的结构图。可以有n多个子控制器，每一个子控制器都包含一个默认的navigationitem，navigationitem中又包括了常用到的title，backbarbuttonitem，left和right barbuttonitem，titleview
//隐藏navigationbar的方法
self.navigationController?.hidesBarsOnTap = true //动态点击隐藏和展示
self.navigationController?.hidesBarsOnSwipe = true //动态滑动隐藏和展示，还比如tableview等滑动的时候
self.navigationController?.hidesBarsWhenVerticallyCompact = true //当屏幕发生横向旋转的时候动态隐藏掉导航栏
self.navigationController?.hidesBarsWhenKeyboardAppears = true //当键盘弹出时动态隐藏掉导航栏
self.navigationController?.hidesBottomBarWhenPushed = true //当视图被push（就是nav的push）完之后是否隐藏底层的bar，YES表示隐藏，NO表示不隐藏。
self.navigationController?.isNavigationBarHidden // 判断是否navigationbar已经被隐藏了
//隐藏navigationbar的手势回调方法单击
lazy var barHideOnTap = self.navigationController?.barHideOnTapGestureRecognizer
//隐藏navigationbar的手势回调方法滑动
lazy var barHideOnSwipe = self.navigationController?.barHideOnSwipeGestureRecognizer
barHideOnTap?.addTarget(self, action: #selector(onTapGestureRecognizerSelect(gender:)))
barHideOnSwipe?.addTarget(self, action: #selector(onSwipeGestureRecognizerSelect(gender:)))
@objc func onSwipeGestureRecognizerSelect(gender: UISwipeGestureRecognizer) {
//isNavigationBarHidden 判断navigationbar是否被隐藏了
if self.navigationController?.isNavigationBarHidden == true {
print("navigation bar 被隐藏了")
} else {
print("navigation bar 显示了")
}
}
@objc func onTapGestureRecognizerSelect(gender: UITapGestureRecognizer) {
//isNavigationBarHidden 判断navigationbar是否被隐藏了
if self.navigationController?.isNavigationBarHidden == true {
print("navigation bar 被隐藏了")
} else {
print("navigation bar 显示了")
}
}
lazy var topViewController = self.navigationController?.topViewController
//当前可见的viewcontroller
lazy var visibleViewController = self.navigationController?.visibleViewController
//当前在栈中存在的所有view controller
lazy var viewControllers = self.navigationController?.viewControllers
