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
370
Deep Dive Work Manager
cdsap
0
340
Advanced Topics Android
cdsap
0
120
Kotlin: Server-Client
cdsap
0
100
Droidcon Dubai : Kotlin - Server - Client
cdsap
0
67
Other Decks in Technology
See All in Technology
テストを軸にした生き残り術
kworkdev
PRO
0
210
自作JSエンジンに推しプロポーザルを実装したい!
sajikix
1
190
未経験者・初心者に贈る!40分でわかるAndroidアプリ開発の今と大事なポイント
operando
5
730
TS-S205_昨年対比2倍以上の機能追加を実現するデータ基盤プロジェクトでのAI活用について
kaz3284
1
210
研究開発と製品開発、両利きのロボティクス
youtalk
1
530
RSCの時代にReactとフレームワークの境界を探る
uhyo
10
3.5k
「どこから読む?」コードとカルチャーに最速で馴染むための実践ガイド
zozotech
PRO
0
540
スマートファクトリーの第一歩 〜AWSマネージドサービスで 実現する予知保全と生成AI活用まで
ganota
2
270
ハードウェアとソフトウェアをつなぐ全てを内製している企業の E2E テストの作り方 / How to create E2E tests for a company that builds everything connecting hardware and software in-house
bitkey
PRO
1
160
COVESA VSSによる車両データモデルの標準化とAWS IoT FleetWiseの活用
osawa
1
350
はじめてのOSS開発からみえたGo言語の強み
shibukazu
3
890
Django's GeneratedField by example - DjangoCon US 2025
pauloxnet
0
150
Featured
See All Featured
Rebuilding a faster, lazier Slack
samanthasiow
83
9.2k
Keith and Marios Guide to Fast Websites
keithpitt
411
22k
Java REST API Framework Comparison - PWX 2021
mraible
33
8.8k
GitHub's CSS Performance
jonrohan
1032
460k
What's in a price? How to price your products and services
michaelherold
246
12k
Optimising Largest Contentful Paint
csswizardry
37
3.4k
Stop Working from a Prison Cell
hatefulcrawdad
271
21k
Testing 201, or: Great Expectations
jmmastey
45
7.7k
The Cult of Friendly URLs
andyhume
79
6.6k
For a Future-Friendly Web
brad_frost
180
9.9k
Art, The Web, and Tiny UX
lynnandtonic
303
21k
Fantastic passwords and where to find them - at NoRuKo
philnash
52
3.4k
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