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
81
State of Testing in Kotlin
cdsap
0
250
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
95
Droidcon Dubai : Kotlin - Server - Client
cdsap
0
61
Other Decks in Technology
See All in Technology
AWS Summit Japan 2025 Community Stage - App workflow automation by AWS Step Functions
matsuihidetoshi
1
160
プロダクトエンジニアリング組織への歩み、その現在地 / Our journey to becoming a product engineering organization
hiro_torii
0
120
菸酒生在 LINE Taiwan 的後端雙刀流
line_developers_tw
PRO
0
1.1k
VISITS_AIIoTビジネス共創ラボ登壇資料.pdf
iotcomjpadmin
0
150
Model Mondays S2E02: Model Context Protocol
nitya
0
200
TechLION vol.41~MySQLユーザ会のほうから来ました / techlion41_mysql
sakaik
0
160
OAuth/OpenID Connectで実現するMCPのセキュアなアクセス管理
kuralab
5
910
ハノーバーメッセ2025座談会.pdf
iotcomjpadmin
0
150
Welcome to the LLM Club
koic
0
150
データプラットフォーム技術におけるメダリオンアーキテクチャという考え方/DataPlatformWithMedallionArchitecture
smdmts
5
590
Witchcraft for Memory
pocke
1
150
AWS アーキテクチャ作図入門/aws-architecture-diagram-101
ma2shita
29
9.6k
Featured
See All Featured
Speed Design
sergeychernyshev
31
1k
It's Worth the Effort
3n
184
28k
Responsive Adventures: Dirty Tricks From The Dark Corners of Front-End
smashingmag
252
21k
We Have a Design System, Now What?
morganepeng
53
7.6k
Balancing Empowerment & Direction
lara
1
350
Performance Is Good for Brains [We Love Speed 2024]
tammyeverts
10
920
The Myth of the Modular Monolith - Day 2 Keynote - Rails World 2024
eileencodes
26
2.8k
What’s in a name? Adding method to the madness
productmarketing
PRO
22
3.5k
StorybookのUI Testing Handbookを読んだ
zakiyama
30
5.8k
Become a Pro
speakerdeck
PRO
28
5.4k
How to Think Like a Performance Engineer
csswizardry
24
1.7k
For a Future-Friendly Web
brad_frost
179
9.8k
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