ViewController是App最基础的结构, 一个App由1到多个ViewController组成,
ViewController扮演MVC模式中的C(Controller), 展示并管理子视图树结构.
通过子类化UIViewController来实现实现自定义数据模型和视图之间的逻辑和通信
ViewController 分类
- Content ViewController 直接管理内容子View显示
- Container ViewController 以不同的方式管理和显示子ViewController
ViewController 展示和过渡
presenting view controller vs presented view controller
ViewController 显示
- segue
- showViewController:sender:
- presentViewControllerAnimated:completion:
ViewController 关闭
在presenting view controller中调用dismissViewControllerAnimated:completion:关闭一个presented view controller.
presented view controller返回数据用delegation模式, 参考UIImagePickerController和UIImagePickerControllerDelegate