Lets talk in / Dilo en Kotlin

Talk about Kotlin basics for:

- http://pataconf.com/
- Meetup Medellin Java https://www.meetup.com/es-ES/medellin-java/events/235359537

Transcript

1. Lets talk in / Dilo en Daniel Gomez Rico Android Lead Developer at Barista Ventures +danielgomezrico @aquicaipivara https://github.com/JetBrains/kotlin v 1.0.4
2. Designed to avoid common problems NullPointerException Transactions Ceremonies 
 (begin(), do(t), finish()) Casting hashCode(), equals(), Y toString() default arguments named arguments Inmutable
 Mutable
 Collections StringBuilder
3. Tools
4. Communities for help
5. Release History february 15 1.0.0 September 22 1.0.4 June 30 1.0.3 May 13 1.0.2 March 16 1.0.1 2010 2016 Nov 8 1.0.5
6. Lets see some code…
7. var name: String = "Nana" Variables
8. var name: String = null
9. var name: String? = null
10. Elvis operator
 o null-coalescing operator If left is null then use right value ?: fun showDialog(text: String?) = print(text ?: "Empty")
11. Elvis operator
 o null-coalescing operator If left is null then use right value ?: fun showDialog(text: String?) = print(text ?: "Empty")
12. Elvis operator
 o null-coalescing operator If left is null then use right value ?: fun showDialog(text: String?) = print(text ?: "Empty")
13. Elvis operator
 o null-coalescing operator If left is null then use right value ?: fun showDialog(text: String?) = print(text ?: "Empty")
14. class Person(val name: String, var age: Int) Classes
15. class Person(val name: String, var age: Int)
 
 val person = Person("Clark Kent", age = 1)
 print("${person.name} ${person.age}") Clark Kent 1
16. data class Person(val name: String, var age: Int)
 
 val person = Person("Clark Kent", age = 1)
 print(person) Person(name=Clark Kent, age=1)
17. var numbers = listOf(1, 2, 3, 4)
 numbers.add(1) Collections
18. var numbers = mutableListOf(1, 2, 3, 4)
 numbers.add(1)
19. interface Operation
 
 interface Transactor {
 fun begin()
 fun finish()
 fun add(operation: Operation)
 } Ceremonies…
20. interface Operation
 
 interface Transactor {
 fun begin()
 fun finish()
 fun add(operation: Operation)
 } val transactor = TransactorImpl()
 
 transactor.begin()
 transactor.add(Operation())
 transactor.finish()
21. interface Operation
 
 interface Transactor {
 fun begin()
 fun finish()
 fun add(operation: Operation)
 } val transactor = TransactorImpl()
 
 transactor.begin()
 transactor.add(Operation())
 transactor.finish()
22. interface Operation
 
 interface Transactor {
 fun begin()
 fun finish()
 fun add(operation: Operation)
 } val transactor = TransactorImpl()
 
 transactor.begin()
 transactor.add(Operation())
 transactor.finish()
23. fun Transactor.safeRun(func: () -> Unit) {
 begin()
 func()
 finish()
 } val transactor = TranstorImpl()
 transactor.safeRun({ transactor.add(Operation()) })
24. fun Transactor.safeRun(func: () -> Unit) {
 begin()
 func()
 finish()
 } val transactor = TranstorImpl()
 transactor.safeRun { transactor.add(Operation()) }
25. fun Transactor.safeRun(func: () -> Unit) {
 begin()
 func()
 finish()
 } val transactor = TranstorImpl()
 transactor.safeRun { transactor.add(Operation()) }
26. fun Transactor.safeRun(func: () -> Unit) {
 begin()
 func()
 finish()
 } val transactor = TranstorImpl()
 transactor.safeRun { transactor.add(Operation()) }
27. fun Transactor.safeRun(func: Transactor.() -> Unit) {
 begin()
 func()
 finish()
 } val transactor = TranstorImpl()
 transactor.safeRun { add(Operation()) }
28. fun main(args: Array<String>) {
 val age = 2
 val name = "Superman"
 val text = "$name $age"
 
 print(text)
 } Kotlin
29. fun main(args: Array<String>) {
 val age = 2
 val name = "Superman"
 val text = "$name $age"
 
 print(text)
 } Kotlin
30. L3 LINENUMBER 43 L3 NEW java/lang/StringBuilder DUP INVOKESPECIAL java/lang/StringBuilder.<init> ()V ALOAD 2 INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/ StringBuilder; LDC " " INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/ StringBuilder; ILOAD 1 INVOKEVIRTUAL java/lang/StringBuilder.append (I)Ljava/lang/StringBuilder; INVOKEVIRTUAL java/lang/StringBuilder.toString ()Ljava/lang/String; ASTORE 3 ByteCode fun main(args: Array<String>) {
 val age = 2
 val name = "Superman"
 val text = "$name $age"
 
 print(text)
 } Kotlin
31. import kotlin.Metadata;
 import kotlin.jvm.internal.Intrinsics;
 import org.jetbrains.annotations.NotNull;
 
 public final class LiveKt {
 public static final void main(@NotNull String[] args) {
 Intrinsics.checkParameterIsNotNull(args, "args");
 byte age = 2;
 String name = "Superman";
 (new StringBuilder()).append(name).append(" ").append(age).toString();
 }
 } Java fun main(args: Array<String>) {
 val age = 2
 val name = "Superman"
 val text = "$name $age"
 
 print(text)
 } Kotlin
32. Interoperable with java 100% JVM
33. “Type Match” MutableCollection<String> Collection<String> Int Integer int Collection<String> Kotlin Java
34. Caution 1 Kotlin val list = findNames()
 list.add("thing") fun findNames(): List<String> {
 //...
 }
35. Caution 1 Kotlin Java List<String> list = findNames();
 list.add("thing"); fun findNames(): List<String> {
 //...
 } val list = findNames()
 list.add("thing")
36. Caution 2 Kotlin fun findNames(): MutableList<String> {
 //...
 } val list = findNames()
 list.add(null)
37. Caution 2 Kotlin fun findNames(): MutableList<String> {
 //...
 } Java List<String> list = findNames();
 list.add(null); val list = findNames()
 list.add(null)
38. And more but ajá…
39. Try without installs try.kotlinlang.org Kotlin Koans Online
40. MVP App List of services Apk: 4 MB with proguard
41. Internal Library for testing Debug artist
42. Banjen - Brasilian Banjo Tunner github Apk 1.93 MB with proguard
43. Reference Google images… iconfinder.com Jake Wharton - Android Development with Kotlin Jake Wharton - Advancing Android Development with the Kotlin Language Better Android Development with Kotlin and Gradle by Ty Smith & Yohan Hartanto
44. Thanks to , and everyone! https://www.meetup.com/es-ES/coltlin/ Anímense a Col-tlin We are hiring -> david@barista-v.com or +danielgomezrico
45. Thanks to , and everyone! https://www.meetup.com/es-ES/coltlin/ Anímense a Col-tlin We are hiring -> david@barista-v.com or +danielgomezrico