1. What the iOS App Lifecycle is
2. App states in iOS
3. Difference between foreground, inactive, background, suspended, and terminated
4. AppDelegate responsibilities
5. SceneDelegate responsibilities
6. Relationship between app lifecycle and UI lifecycle
7. When lifecycle callbacks are triggered
8. Where to pause work
9. Where to resume work
10. Memory behavior in different app states
11. Real-world scenarios where app lifecycle matters

1. What the iOS App Lifecycle Is

The iOS App Lifecycle describes how an app transitions between different states as it launches, becomes active, moves to the background, and is eventually terminated.

These transitions are controlled by the system and are communicated to the app via AppDelegate and SceneDelegate callbacks.

2. App States in iOS

An iOS app can be in one of the following states:

• Active (Foreground)