Java?.Kotlin!!

Platica para el meetup de Kotlin nights en la CDMX

Transcript

1. Java?.Kotlin!! Sebastian Tellez @gorrotowi github.com/gorrotowi
2. Java?.Kotlin!! Kotlin es un lenguaje de programación desarrollado por JetBrains. Es funcional, esta diseñado para correr sobre la JVM, Android y Web
3. Java?.Kotlin!! Funcional Lambdas 100% interoperable con Java (JVM) NullSafety
4. Java?.Kotlin!! Ryan (James) Gosling a.k.a Java father
5. Java?.Kotlin!!
6. Java?.Kotlin!!
7. Java?.Kotlin!!
8. Java?.Kotlin!! private String numberString; int number = Integer.parseInt(numberString); //java
9. Java?.Kotlin!!
10. Java?.Kotlin!! private String numberString; if(numberString != null){ int number = Integer.parseInt(numberString); } private String numberString; int number = Integer.parseInt(numberString); //java
11. Java?.Kotlin!! var a: String = "abc" a = null // compilation error var b: String? = "abc" b = null // ok
12. Java?.Kotlin!! var a: String = "abc" val sizeA = a.length var b: String? = "abc" b = null // ok var sizeB = b.length //error: variable 'b' can be null
13. Java?.Kotlin!! if (b != null && b.length > 0) { print("String of length ${b.length}") } else { print("Empty string") }
14. Java?.Kotlin!! var a: String = "abc" val sizeA = a.length var b: String? = "abc" b = null // ok var sizeB = b.length //error: variable 'b' can be null
15. Java?.Kotlin!! var sizeB = b?.length
16. Java?.Kotlin!! ?:
17. Java?.Kotlin!! val l = if (b != null) b.length else -1
18. Java?.Kotlin!! val l = b?.length ?: -1
19. Java?.Kotlin!! fun foo(node: Node): String? { val parent = node.getParent() ?: return null val name = node.getName() ?: throw IllegalArgumentException("name expected") // ... }
20. Java?.Kotlin!! private String numberString; if(numberString != null){ int number = Integer.parseInt(numberString); } private String numberString; int number = Integer.parseInt(numberString); //java //Kotlin
21. Java?.Kotlin!! val aInt: Int? = numberString as? Int //Kotlin
22. Java?.Kotlin!! val listWithNulls: List<String?> = listOf("A", null) for (item in listWithNulls) { item?.let { println(it) } // prints A and ignores null }
23. Java?.Kotlin!! val fooFighters = b!!.length
24. Java?.Kotlin!!
25. Java?.Kotlin!! https://kotlinlang.org/docs/reference/ https://fabiomsr.github.io/from-java-to-kotlin/index.html https://try.kotlinlang.org/
26. Java?.Kotlin!! Sebastian Tellez @gorrotowi github.com/gorrotowi GRACIAS!!