John, an Android developer at Rakuten Viki, will give a presentation on Kotlin initialization. The presentation will cover primary and secondary constructors, initializer blocks, property initialization order, delaying initialization using lazy delegation, and initialization gotchas. It will end with a challenge problem about the legend of King Arthur and Excalibur.

1. Initialization
Kotlin Study Group
John

2. Hi, I am John
- Android Developer
- Work on Rakuten Viki
- Use Kotlin for 2 years
- Linkedin:
https://www.linkedin.com/in/chang-john-0a95237a/

3. Outline
- Preface
- Constructors
- Primary Constructor
- Secondary Constructor
- Initializer block
- Property Initialization
- Initialization Order
- Delaying mechanism for initialization
- Delaying Initialization vs Nullable Type
- Lazy Initialization
- Initialization Gotchas
- Challenge: The Riddle of Excalibur

4. Preface
- When you read, think what’s different syntax between Java and Kotlin.
- Kotlin is null safety rule.
- Kotlin is idiomatic language, meaning less boilerplate.
- The class in Kotlin contains class property, not only field(data)
- Property = field + accessor(get/set)
- Class Property must give initial value, except computed property

5. Constructors - similar with Java Constructor Syntax

6. Kotlin Primary Constructor - more than you think

7. Second Constructor - alternative constructed way

8. Default arguments and Named arguments support

9. Initializer block

10. Property Initialization

11. Initialization Order
- Primary Constructor
- Secondary Constructor
- Init Block
- Property Initialization

12. Initialization Order

13. Initialization Order
1. Primary constructor
2. Property initialization/Init order depend on who write first
3. Secondary constructor

14. Delaying Initialization

15. Nullable Property

16. Lazy initialization

17. What's mystery of lazy delegation?

18. Initialization Gotchas
1. Refer to property before at init block
2. Refer to property before at property initialization
3. Complexity assignment in the initialization

19. Challenge: The Riddle of Excalibur

20. Reference
- When to Use Lazy or Lateinit
- Programmer Dictionary: Delegation vs Composition
- Simple one-liner ViewBinding in Fragments and Activities with Kotlin