“Hello Kotlin” Kotlin

2017.08.22 Kenichi Kambara (@korodroid)

Kotlin LT

Kotlin

…

# !!!

…

About me

• •

• Droidcon Stockholm 2014 • Droidcon Spain 2014 • Droidcon Amsterdam 2013 • Droidcon Paris 2013 • Smartphone & Tablet 2014 Spring Tokyo • Developers Summit 2013 Summer & 2015

•

• Mobile Dev Blog

• Android

• NTT

(@korodroid)

Introduction

• Kotlin

• “Hello Kotlin”

Kotlin

http://www.iplatform.org/blog/sekai-phone

“Hello Kotlin”

Android Studio

[Menu]Code->Convert Java File to Kotlin File

*.kt Java Copy&Paste

Smart Cast

fun demo1(x: Any) { if (x is String) { print(x.length) // Kotlin }

fun demo2() { val y: String? = “Hoge" if(y != null ) { print(y.length) // Not-Null } }

fun orderPizza(size: Size, egg: Boolean, tuna: Boolean, ham: Boolean, pine: Boolean)

orderPizza(Size.L, true, false, true, false)

// 3 …

Java

orderPizza(size = Size.L, egg = true, tuna = false, ham = true, pine = false)

Kotlin

( )

fun orderPizza(size: Size, egg: Boolean = false, tuna: Boolean = false, ham: Boolean = false, pine: Boolean = false)

// 3 …

Java

orderPizza(size = Size.L)Kotlin

//

( )

fun String.appendHonorific(): String = "${this} "

“ ”.appendHonorific() // “ ”

String

Kotlin

• fun • var,val ( ) • ?, !!

• data ( ) • object ( ) • it ( 1 ) • lazy, lateinit ( ) • when (if, else if )

ref. Kotlin Official Site / Idioms https://kotlinlang.org/docs/reference/idioms.html

Conclusion

Appendix( )

- Please let me know if you have any requests such as technical speeches, technical writings and so on.

Facebook:http://fb.com/kanbara.kenichi Google+:+Kenichi Kambara LinkedIn:http://www.linkedin.com/in/korodroid Twitter:@korodroid

Thank you so much.