Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Kotlin is here
Search
Iñaki Villar
July 09, 2017
Technology
0
110
Kotlin is here
Intro to Kotlin.
Google IO Extended Cebu
Iñaki Villar
July 09, 2017
Tweet
Share
More Decks by Iñaki Villar
See All by Iñaki Villar
Scaling Android Builds in Pandemic Times
cdsap
1
150
Building Android Projects with kts
cdsap
2
280
The Build Shrugged
cdsap
1
82
State of Testing in Kotlin
cdsap
0
260
Dexs, R8 and 3.3
cdsap
0
360
Deep Dive Work Manager
cdsap
0
340
Advanced Topics Android
cdsap
0
110
Kotlin: Server-Client
cdsap
0
99
Droidcon Dubai : Kotlin - Server - Client
cdsap
0
64
Other Decks in Technology
See All in Technology
Tableau API連携の罠!?脱スプシを夢見たはずが、逆に依存を深めた話
cuebic9bic
3
210
ロールが細分化された組織でSREと協働するインフラエンジニアは何をするか? / SRE Lounge #18
kossykinto
0
200
Claude Codeは仕様駆動の夢を見ない
gotalab555
22
5k
UDDのススメ - 拡張版 -
maguroalternative
1
120
AI関数が早くなったので試してみよう
kumakura
0
170
【OptimizationNight】数理最適化のラストワンマイルとしてのUIUX
brainpadpr
1
360
大規模イベントに向けた ABEMA アーキテクチャの遍歴 ~ Platform Strategy 詳細解説 ~
nagapad
0
190
2時間で300+テーブルをデータ基盤に連携するためのAI活用 / FukuokaDataEngineer
sansan_randd
0
130
마라톤 끝의 단거리 스퍼트: 2025년의 AI
inureyes
PRO
1
690
✨敗北解法コレクション✨〜Expertだった頃に足りなかった知識と技術〜
nanachi
1
590
Kiroでインフラ要件定義~テスト を実施してみた
nagisa53
3
310
【CEDEC2025】大規模言語モデルを活用したゲーム内会話パートのスクリプト作成支援への取り組み
cygames
PRO
2
780
Featured
See All Featured
Practical Tips for Bootstrapping Information Extraction Pipelines
honnibal
PRO
21
1.4k
Java REST API Framework Comparison - PWX 2021
mraible
32
8.8k
Fireside Chat
paigeccino
38
3.6k
VelocityConf: Rendering Performance Case Studies
addyosmani
332
24k
StorybookのUI Testing Handbookを読んだ
zakiyama
30
6k
Code Reviewing Like a Champion
maltzj
524
40k
How STYLIGHT went responsive
nonsquared
100
5.7k
Making Projects Easy
brettharned
117
6.3k
Understanding Cognitive Biases in Performance Measurement
bluesmoon
29
1.8k
Practical Orchestrator
shlominoach
190
11k
How to Think Like a Performance Engineer
csswizardry
25
1.8k
Designing for Performance
lara
610
69k
Transcript
Kotlin is here Too much fun
None
None
None
None
None
.java java compiler .class .jar dex
.kt .java java compiler .class .jar dex kotlin compiler
class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) }
class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) }
class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) }
class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) }
override fun onResume() { super.onResume() mAutofillManager?.registerCallback(mAutofillCallback) } override fun onPause()
{ super.onPause() mAutofillManager?.unregisterCallback(mAutofillCallback) }
None
var index = structure.addChildCount(chidrenSize) val context : Context = request.getContext()
Variables
var index = structure.addChildCount(chidrenSize) val context : Context = request.getContext()
Variables
var index = structure.addChildCount(chidrenSize) val context : Context = request.getContext()
Variables
var index = structure.addChildCount(chidrenSize) val context : Context = request.getContext()
Variables var index : Int = structure.addChildCount(chidrenSize)
var textValue : String = "" textValue = "alo" var
index = structure.addChildCount(chidrenSize) val context : Context = request.getContext() Variables
var textValue : String = "" textValue = "alo" var
index = structure.addChildCount(chidrenSize) val context : Context = request.getContext() Variables val textValue : String = "" textValue = "alo"
var textValue : String = "" textValue = "alo" var
index = structure.addChildCount(chidrenSize) val context : Context = request.getContext() Variables val textValue : String = "" textValue = "alo"
class SimpleClass Classes/Objects
class SimpleClass open class SimpleClass Classes/Objects
class SimpleClass open class SimpleClass class SimpleClass : BaseClass() Classes/Objects
class SimpleClass open class SimpleClass class SimpleClass : BaseClass() class
SimpleClass : SimpleInterface Classes/Objects
class SimpleClass open class SimpleClass class SimpleClass : BaseClass() class
SimpleClass : SimpleInterface object SimpleClass Classes/Objects
class SimpleClass(value: String) Classes/Objects
class SimpleClass(value: String) Classes/Objects class Team { val player :
String var goals : Int }
class SimpleClass(value: String) Classes/Objects class Team { val player :
String var goals : Int }
class SimpleClass(value: String) Classes/Objects class Team { val player :
String = “Rivaldo” var goals : Int = 0 }
class SimpleClass(value: String) Classes/Objects val myPlayer = Team(“Rivaldo”,0) class Team(player:
String, goals: Int)
class SimpleClass(value: String) Classes/Objects val myPlayer = Team(“Rivaldo”,0) class Team(player:
String) { var goals: Int = 0 } class Team(player: String, goals: Int)
class SimpleClass(value: String) Classes/Objects val myPlayer = Team(“Rivaldo”,0) class Team(player:
String) { var goals: Int = 0 } val myPlayer = Team("Rivaldo") myPlayer.goals = 3 class Team(player: String, goals: Int)
Classes/Objects var goals: Int = 0 set(value) { if (goals
> 5) { log(“$player has scored multiple goals") field = value } }
Classes/Objects var goals: Int = 0 set(value) { if (goals
> 5) { log(“$player has scored multiple goals") field = value } } val isEmpty get() = this.size == 0
class SimpleClass(value: String){ init { log() } } Classes/Objects
class SimpleClass(value: String){ init { log() } } Classes/Objects class
Button : View { constructor(ctx: Context) : super(ctx) constructor(ctx: Context, attr: AttributeSet) : super(ctx, attr) }
Classes/Objects data class Team (val name : String, val goals
: Int)
Classes/Objects data class Team (val name : String, val goals
: Int) hashCode - toString - equals
Classes/Objects class A { companion object { fun bar() {
println("Companion Object") } } } data class Team (val name : String, val goals : Int) hashCode - toString - equals
Classes/Objects class A { companion object { fun bar() {
println("Companion Object") } } } data class Team (val name : String, val goals : Int) hashCode - toString - equals A.bar()
Smart Casts public void printTypeProperty(Object object) { if (object instanceof
String) { System.out.print(((String) object).isEmpty()); } else if (object instanceof Integer){ System.out.print(((Integer) object).intValue()); } else if (object instanceof Boolean){ System.out.print(((Boolean) object).booleanValue()); } }
fun printTypeProperty(any: Any) { if (any is String) { println(any.length)
} else if (any is Int) { println(any.plus(1)) } else if (any is Boolean) { println(any.not()) } } Smart Casts public void printTypeProperty(Object object) { if (object instanceof String) { System.out.print(((String) object).isEmpty()); } else if (object instanceof Integer){ System.out.print(((Integer) object).intValue()); } else if (object instanceof Boolean){ System.out.print(((Boolean) object).booleanValue()); } }
fun printTypeProperty(any: Any) { if (any is String) { println(any.length)
} else if (any is Int) { println(any.plus(1)) } else if (any is Boolean) { println(any.not()) } } Smart Casts public void printTypeProperty(Object object) { if (object instanceof String) { System.out.print(((String) object).isEmpty()); } else if (object instanceof Integer){ System.out.print(((Integer) object).intValue()); } else if (object instanceof Boolean){ System.out.print(((Boolean) object).booleanValue()); } }
sealed class Expr data class Const(val number: Double) : Expr()
data class Sum(val e1: Expr, val e2: Expr) : Expr() object NotANumber : Expr() Sealed Classes
sealed class Expr data class Const(val number: Double) : Expr()
data class Sum(val e1: Expr, val e2: Expr) : Expr() object NotANumber : Expr() Sealed Classes
sealed class Expr data class Const(val number: Double) : Expr()
data class Sum(val e1: Expr, val e2: Expr) : Expr() object NotANumber : Expr() Sealed Classes
sealed class Expr data class Const(val number: Double) : Expr()
data class Sum(val e1: Expr, val e2: Expr) : Expr() object NotANumber : Expr() fun eval(expr: Expr): Double = when(expr) { is Const -> expr.number is Sum -> eval(expr.e1) + eval(expr.e2) NotANumber -> Double.NaN } Sealed Classes
sealed class Expr data class Const(val number: Double) : Expr()
data class Sum(val e1: Expr, val e2: Expr) : Expr() object NotANumber : Expr() fun eval(expr: Expr): Double = when(expr) { is Const -> expr.number is Sum -> eval(expr.e1) + eval(expr.e2) NotANumber -> Double.NaN } Sealed Classes
sealed class Expr data class Const(val number: Double) : Expr()
data class Sum(val e1: Expr, val e2: Expr) : Expr() object NotANumber : Expr() fun eval(expr: Expr): Double = when(expr) { is Const -> expr.number is Sum -> eval(expr.e1) + eval(expr.e2) NotANumber -> Double.NaN } Sealed Classes
Interfaces class SimpleClass : SimpleInterface
interface SimpleInterface { fun doSomething() } Interfaces class SimpleClass :
SimpleInterface
interface SimpleInterface { fun doSomething() } interface SimpleInterface { fun
doSomething() fun doAnotherThing() = println("default") } Interfaces class SimpleClass : SimpleInterface
int strLen(String s){ return s.length(); } Nullability
fun strLen(s: String) = s.length int strLen(String s){ return s.length();
} Nullability
fun strLen(s: String) = s.length int strLen(String s){ return s.length();
} fun strLen(s: String?) = … Nullability
fun strLen(s: String) = s.length int strLen(String s){ return s.length();
} fun strLen(s: String?) = … fun strLen(s: String?): Int = if (s != null) s.length else 0 Nullability
fun toUpperCase(s: String?): String? Nullability
fun toUpperCase(s: String?): String? fun toUpperCase(s: String?): String? = s?.toUpperCase()
Nullability
fun toUpperCase(s: String?): String? fun toUpperCase(s: String?): String? = s?.toUpperCase()
Nullability
fun toUpperCase(s: String?): String? fun toUpperCase(s: String?): String? = s?.toUpperCase()
fun length(s: String?): Int Nullability
fun toUpperCase(s: String?): String? fun toUpperCase(s: String?): String? = s?.toUpperCase()
fun length(s: String?): Int fun length(s: String?): Int = s?.length ?: 0 Nullability
fun toUpperCase(s: String?): String? fun toUpperCase(s: String?): String? = s?.toUpperCase()
fun length(s: String?): Int fun length(s: String?): Int = s?.length ?: 0 Nullability
fun toUpperCase(s: String?): String? fun toUpperCase(s: String?): String? = s?.toUpperCase()
fun length(s: String?): Int fun length(s: String?): Int = s?.length ?: 0 Nullability
this as? PageObjectKt Nullability
this as? PageObjectKt Nullability email?.let { email -> sendEmailTo()}
fun max(a: Int, b: Int): Int { return if (a
> b) a else b } Functions
fun max(a: Int, b: Int): Int { return if (a
> b) a else b } Functions
fun max(a: Int, b: Int): Int { return if (a
> b) a else b } Functions
fun max(a: Int, b: Int): Int { return if (a
> b) a else b } Functions
fun createPlayer(name: String, lastName: String, nickName: String?, city: String?) {
Functions - Named Arguments
fun createPlayer(name: String, lastName: String, nickName: String?, city: String?) {
createPlayer("Inaki", "Villar", null, null) Functions - Named Arguments
fun createPlayer(name: String, lastName: String, nickName: String?, city: String?) {
createPlayer("Inaki", "Villar", null, null) createPlayer("Inaki", "Villar", nickName = null, city = null) Functions - Named Arguments
fun createPlayer(name: String, lastName: String, nickName: String = “", city:
String = "Cebu") Functions - Default Arguments
fun createPlayer(name: String, lastName: String, nickName: String = “", city:
String = "Cebu") createPlayer("Inaki", "Villar") Functions - Default Arguments createPlayer("Inaki", "Villar", "Nine")
fun lengthIsGreaterThanFive(s : String) = s.length > 5 val va
= "myVeryLongString" val isGreaterThanFive = lengthIsGreaterThanFive(va) Extension Functions
fun lengthIsGreaterThanFive(s : String) = s.length > 5 val va
= "myVeryLongString" val isGreaterThanFive = lengthIsGreaterThanFive(va) Extension Functions fun String.lengthIsGreaterThanFive() = this.length > 5
fun lengthIsGreaterThanFive(s : String) = s.length > 5 val va
= "myVeryLongString" val isGreaterThanFive = lengthIsGreaterThanFive(va) Extension Functions fun String.lengthIsGreaterThanFive() = this.length > 5
fun lengthIsGreaterThanFive(s : String) = s.length > 5 val va
= "myVeryLongString" val isGreaterThanFive = lengthIsGreaterThanFive(va) val va = "myVeryLongString" val isGreaterThanFive = va.lengthIsGreaterThanFive() Extension Functions fun String.lengthIsGreaterThanFive() = this.length > 5
Infix Functions infix fun Int.minus(value: Int) = this - value
Infix Functions infix fun Int.minus(value: Int) = this - value
Infix Functions infix fun Int.minus(value: Int) = this - value
val result = 4 minus 2
Infix Functions infix fun Int.minus(value: Int) = this - value
val result = 4 minus 2
Infix Functions infix fun Int.minus(value: Int) = this - value
val result = 4 minus 2 4.minus(2)
Infix Functions infix fun Int.minus(value: Int) = this - value
val result = 4 minus 2 infix fun String.repeat(times: Int) = { var result = "" for (i in 1..times) { result += this } }
Infix Functions infix fun Int.minus(value: Int) = this - value
val result = 4 minus 2 infix fun String.repeat(times: Int) = { var result = "" for (i in 1..times) { result += this } }
Infix Functions infix fun Int.minus(value: Int) = this - value
val result = 4 minus 2 infix fun String.repeat(times: Int) = { var result = "" for (i in 1..times) { result += this } } val multipleA = "a" repeat 10
Lambdas
buttonSend.setOnClickListener(new View.OnClickListener(){ @Override public void onClick(View v){ send(); } });
Lambdas
buttonSend.setOnClickListener(new View.OnClickListener(){ @Override public void onClick(View v){ send(); } });
buttonSend.setOnClickListener(object :OnClickListener{ override fun onClick(view : View){ send(); } }) Lambdas
buttonSend.setOnClickListener(new View.OnClickListener(){ @Override public void onClick(View v){ send(); } });
buttonSend.setOnClickListener(object :OnClickListener{ override fun onClick(view : View){ send(); } }) buttonSend.setOnClickListener(View.OnClickListener { view : View -> doSomething() }) Lambdas
{ x : Int, y: Int -> x + y
} Lambdas
{ x : Int, y: Int -> x + y
} Lambdas
{ x : Int, y: Int -> x + y
} Lambdas
data class Team (val name : String, val goals :
Int) val myLeague = listOf(Team("Sakuvic", 12), Team("Rivaldo",10)) Lambdas
data class Team (val name : String, val goals :
Int) val myLeague = listOf(Team("Sakuvic", 12), Team("Rivaldo",10)) myLeague.maxBy({ p: Team -> p.goals }) Lambdas
data class Team (val name : String, val goals :
Int) val myLeague = listOf(Team("Sakuvic", 12), Team("Rivaldo",10)) myLeague.maxBy({ p: Team -> p.goals }) myLeague.maxBy { p: Team -> p.goals } Lambdas
myLeague.maxBy { it.goals } data class Team (val name :
String, val goals : Int) val myLeague = listOf(Team("Sakuvic", 12), Team("Rivaldo",10)) myLeague.maxBy({ p: Team -> p.goals }) myLeague.maxBy { p: Team -> p.goals } Lambdas
None
private val mOnNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item -> when (item.itemId)
{ R.id.navigation_home -> { message.setText(R.string.title_home) return@OnNavigationItemSelectedListener true } R.id.navigation_dashboard -> { message.setText(R.string.title_dashboard) return@OnNavigationItemSelectedListener true } R.id.navigation_notifications -> { message.setText(R.string.title_notifications) return@OnNavigationItemSelectedListener true } } false Future is here
Much more Type System Delegation High Order Functions & FP
Operator Generics DSL
None
[email protected]
@inyaki_mwc Thanks