Kotlin 101#1

Transcript

2. REACTIVE PROGRAMMING (ANDROID) KOTCHAPHAN MUANGSAN ▸ Software Developer Facebook: @werockstar Github: @werockstar Medium: @werockstar
3. Special Thanks @werockstar “คุณเอาหนังสือ Kotlin ไปอ่านนะ แล้วมาสอนผมด้วย”
4. @werockstar Kotlin is a statically typed programming language by Jetbrains
5. @werockstar
6. @werockstar Target Platforms Server-side, Android, anywhere Java runs, Native
7. @werockstar Now official on Android
8. @werockstar Functional and object-oriented
9. @werockstar Tools - IntelliJ IDEA - Eclipse - Android Studio - try.kotlinlang.org - Interactive shell (REPL)
10. @werockstar Basic fun main(args: Array<String>) { println("Hello, Kotlin world!”) }
11. @werockstar Declare a variable val kotlinString: String // Immutable var kotlinInt: Int // Mutable Recommend: declare all variable in Kotlin with val. var only necessary. Using immutable references, objects and functions without side effects.
12. @werockstar Declare a variable#2 Type inference val kotlin = 2010
13. @werockstar Expression body fun geekyBase() = "Computer Training School"
14. @werockstar Block body fun geekyBase(): String { return "Computer school training" }
15. @werockstar String templates val kotlin = "Kotlin" val java = "Java" println("Using $kotlin without $java”) // println("Using ${kotlin} without ${java}”)
16. @werockstar String templates#2 fun main(args: Array<String>) { println("${if (isBeKotlin()) "Kotlin" else "Java"}!") } Expression within string template
17. @werockstar Function fun keyword used to declare a function in Kotlin
18. @werockstar if-else expression if(kotlin > java) { println("Kotlin") }else { println(“Kotlin") }
19. @werockstar when expression when(isBestForAndroid()) { "kotlin" -> println("Kotlin") else -> println("Kotlin") }
20. @werockstar Extension Function fun View.toVisible() = View.VISIBLE
21. @werockstar Class open class Student { } final by default
22. @werockstar Null safety Safe Calls: "?." Elvis Operator: "?:" Safe-cast: "as?" Not-null assertions: "!!" function: ".let" Late-initialized properties: "lateinit" By default, all type parameters of functions and classes in Kotlin are nullable
23. @werockstar github.com/WeRockStar/Dagger2