This document discusses the view controller life cycle in iOS. It includes diagrams showing the different states a view controller can be in like loaded, appeared, disappeared, and not loaded. It also lists the methods called during transitions between states, such as viewWillAppear and viewDidDisappear. The document explains that understanding the view controller life cycle is important and provides an example lab activity to practice tracking the order of life cycle events.

1. Unit 3—Lesson 8:
View Controller Life Cycle

2. View controller life cycle
Not Loaded
Disappeared
Appear
viewWillDisappear(_:)
viewWillAppear(_:)
viewDidLoad()
View Loaded
View Not Loaded
viewDidDisappear(_:) viewDidAppear(_:)

3. viewDidLoad( )
View controller life cycle
Not Loaded
Disappeared
Appear
viewWillDisappear(_:)
viewWillAppear(_:)
viewDidLoad()
View Loaded
View Not Loaded
viewDidDisappear(_:) viewDidAppear(_:)

4. View event management
viewWillAppear(_:)
viewDidAppear(_:)
viewWillDisappear(_:)
viewDidDisappear(_:)
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
// Add your code here
}

5. viewWillAppear(_:)
View event management
Not Loaded
Disappeared
Appear
viewWillDisappear(_:)
viewWillAppear(_:)
viewDidLoad()
View Loaded
View Not Loaded
viewDidDisappear(_:) viewDidAppear(_:)

6. viewDidAppear(_:)
View event management
Not Loaded
Disappeared
Appear
viewWillDisappear(_:)
viewWillAppear(_:)
viewDidLoad()
View Loaded
View Not Loaded
viewDidDisappear(_:) viewDidAppear(_:)

7. viewWillDisappear(_:)
View event management
Not Loaded
Disappeared
Appear
viewWillDisappear(_:)
viewWillAppear(_:)
viewDidLoad()
View Loaded
View Not Loaded
viewDidDisappear(_:) viewDidAppear(_:)

8. viewDidDisappear(_:)
View event management
Not Loaded
Disappeared
Appear
viewWillDisappear(_:)
viewWillAppear(_:)
viewDidLoad()
View Loaded
View Not Loaded
viewDidDisappear(_:) viewDidAppear(_:)

9. View Controller Life Cycle
Unit 3—Lesson 8
This lesson will explain more about the view controller life cycle so you can
understand the infinite potential of this important class

10. Lab: Order of Events
Unit 3—Lesson 8
Further your understanding of the view's life cycle by creating an app that adds to
a label’s text based on the events in the view controller life cycle

11. © 2017 Apple Inc.
This work is licensed by Apple Inc. under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International license.