Documentation URL
https://developer.apple.com/documentation/uikit/core_app/managing_your_app_s_life_cycle?language=objc
APP生命周期状态
管理生命周期事件
https://developer.apple.com/documentation/uikit/core_app/managing_your_app_s_life_cycle?language=objc
-
Launch
初始化APP准备启动；
- APP启动时序
- 执行一次APP配置
-
Activation
APP显示到前台
- 准备
- [ApplicationDelegate applicationDidBecomeActive:]
当APP处于active状态时，回调
- [ApplicationDelegate applicationWillEnterForeground:]
如果APP已经处于background，怎会先调用该方法，之后再回调applicationDidBecomeActive:方法；
- [ViewController viewWillAppear:]
更新视图内容
- [ViewController viewDidAppear:]
在视图出现在屏幕上后回调；
- [ApplicationDelegate applicationDidBecomeActive:]
- 准备
-
Deactivation
APP处于background，被阻塞；
- [ApplicationDelegate applicationWillResignActive:]
首先调用该方法 ；在该过程中会中断app操作和保存用户关键数据；
- [ApplicationDelegate applicationDidEnterBackground:]
APP进入background回调该方法；
- [ApplicationDelegate applicationWillResignActive:]
- Background execution
- Termination
