IOS Uinavgationcontroller, Uinavigationbar, uinavigationitem relationship analysis

The general navigation controller contains 4 objects, Uinavigationcontroller, Uinavigationbar, Uiviewcontroller, Uinavigationitem.

1:uinavigationcontroller

The parent class of Uinavigationcontroller is Uiviewcontroller (Uiviewcontroller, the base class for all controllers), as shown in the relationship:

Uinavigationcontroller is a view container, in the form of a stack manager multiple content Views (Uiviewcontroller) in the swap (press-in) and swap out (eject), itself provides a view to switch the dynamic

Drawing effect.

2:uinavigationbar

The parent class of Uinavigationbar is UIView

Navigaitonbar is the navigation bar, located above the screen, to manage the entire Navigationcontroller Navigationitem, like Navigationcontroller, provides a stack to pipe

Management Item.

3: Uinavigationitem

　　The parent class of Uinavigationitem is NSObject

It contains all the information that needs to be displayed on the navigation bar of the current page : Title,prompt,titleview,leftbarbuttonitem, , Rightbarbuttonitem,backbarbutonitem.

　　Note: There will be a lot of uiviewcontroller in the Uinavigationcontroller, each uiviewcontroller will correspond to one of their own uinavigationitem, to show

the difference between uiviewcontroller. So when we set each page title, we had to use self. Navigationitem.title this property.

IOS Uinavgationcontroller, Uinavigationbar, uinavigationitem relationship analysis