100% Kotlin and Anko

Overview of alternatives to Java in Android, focusing on Kotlin and taking a sneak peek at Anko.

Transcript

1. 100% Kotlin 100% Anko
2. @goncalossilva j.mp/100ka-slides
6. Java?
7. Alternatives?
8. 1 Modern
9. 1 Modern 2 Fast
10. 1 Modern 2 Fast 3 Small
11. 1 Modern 2 Fast 3 Small 4 Interoperable
12. Scala
13. 1 Modern Scala
14. 1 Modern 2 Fast Scala
15. 1 Modern 2 Fast 3 Small Scala
16. 1 Modern 2 Fast 3 Small 4 Interoperable Scala
17. Clojure
18. 1 Modern Clojure
19. 1 Modern 2 Fast Clojure
20. 1 Modern 2 Fast 3 Small Clojure
21. 1 Modern 2 Fast 3 Small 4 Interoperable Clojure
22. Groovy
23. 1 Modern Groovy
24. 1 Modern 2 Fast Groovy
25. 1 Modern 2 Fast 3 Small Groovy
26. 1 Modern 2 Fast 3 Small 4 Interoperable Groovy
27. Swift
28. Swift Modern Fast Small Interoperable
29. Java 10
30. Java 10 Modern Fast Small Interoperable
31. Kotlin
32. 1 Modern 2 Fast 3 Small 4 Interoperable Kotlin
33. class Purchase constructor(value: Int, success: Boolean) { val value = value val success = success }
34. class Purchase(val value: Int, val success: Boolean)
35. data class Purchase(val value: Int, val success: Boolean)
36. data class Customer(val name: String, val purchases: List<Purchase>) data class Purchase(val value: Int, val success: Boolean)
37. data class Customer(val name: String, val purchases: List<Purchase>) data class Purchase(val value: Int, val success: Boolean) object Dataset { val customers: MutableList<Customer> = ArrayList() init { customers.add(Customer( "Gonçalo”, arrayListOf(Purchase(42, true), Purchase(9000, false)))) } }
38. fun successfulPurchases(name: String) : List<Purchase> { val successfulPurchases: MutableList<Purchase> = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }
39. fun successfulPurchases(name: String) : List<Purchase> { val successfulPurchases: MutableList<Purchase> = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }
40. fun successfulPurchases(name: String) : List<Purchase> { val successfulPurchases: MutableList<Purchase> = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }
41. fun successfulPurchases(name: String) : List<Purchase> { val successfulPurchases: MutableList<Purchase> = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }
42. fun successfulPurchases(name: String) : List<Purchase> { val successfulPurchases: MutableList<Purchase> = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }
43. fun successfulPurchases(name: String) : List<Purchase> { val successfulPurchases: MutableList<Purchase> = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }
44. fun successfulPurchases(name: String) : List<Purchase> { val successfulPurchases: MutableList<Purchase> = ArrayList() // Find the customer. val customer = Dataset.customers.find { it.name == name } // Gather successful purchases. if (customer != null) { successfulPurchases.addAll(customer.purchases.filter { it.success } } return successfulPurchases }
45. fun successfulPurchases(name: String) : List<Purchase> { return Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList() }
46. fun successfulPurchases(name: String) : List<Purchase> { return Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList() }
47. fun successfulPurchases(name: String) : List<Purchase> { return Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList() }
48. fun successfulPurchases(name: String) : List<Purchase> { return Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList() }
49. fun successfulPurchases(name: String) : List<Purchase> = Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList()
50. fun successfulPurchases(name: String) : List<Purchase>? = Dataset.customers.find { it.name == name }?.purchases?.filter { it.success }
51. fun Customer.successfulPurchases() : List<Purchase> = purchases.filter { it.success } customer.successfulPurchases() // Works!
52. fun successfulPurchases(name: String) : List<Purchase> { val successfulPurchases: MutableList<Purchase> = ArrayList() var customer: Customer? = null for (c in Dataset.customers) { if (c.name == name) { customer = c break } } if (customer != null) { for (purchase in customer.purchases) { if (purchase.success) successfulPurchases.add(purchase) } } return successfulPurchases }
53. fun successfulPurchases(name: String) : List<Purchase> = Dataset.customers.find { it.name == name }?.purchases? .filter { it.success } ?: emptyList()
54. Higher-order functions, properties, mixins and delegation, extension functions, static nullability checking, automatic casts, reified generics, declaration-site variance, modules and build infrastructure, inline functions, operator overloading, String interpolation, pattern matching, first class IDE support, Java converter, default parameters, infix methods, destructuring declarations, and more...
55. Modern 2 Fast 3 Small 4 Interoperable Kotlin
56. Statically typed byte code Inlined lambdas https://github.com/JetBrains/kotlin-benchmarks Kotlin
57. Modern Fast 3 Small 4 Interoperable Kotlin
58. 5k methods 1MB Smaller and smaller Kotlin
59. Modern Fast Small 4 Interoperable Kotlin
60. 100% interoperable Idiomatic Kotlin with idiomatic Java Annotations for customization Kotlin
61. Modern Fast Small Interoperable Kotlin
62. Modern Fast Small Interoperable Kotlin 5 Android APIs
63. db.beginTransaction() try { db.delete("hackathon", "name = ?", arrayOf("Pixels Camp")) db.setTransactionSuccessful() } finally { db.endTransaction() }
64. inline fun SQLiteDatabase.inTransaction(func: SQLiteDatabase.() -> Unit) { beginTransaction() try { func() setTransactionSuccessful() } finally { endTransaction() } } db.inTransaction { delete("hackathon", "name = ?", arrayOf("Pixels Camp")) }
65. inline fun SQLiteDatabase.inTransaction(func: SQLiteDatabase.() -> Unit) { beginTransaction() try { func() setTransactionSuccessful() } finally { endTransaction() } } db.inTransaction { delete("hackathon", "name = ?", arrayOf("Pixels Camp")) }
66. inline fun SQLiteDatabase.inTransaction(func: SQLiteDatabase.() -> Unit) { beginTransaction() try { func() setTransactionSuccessful() } finally { endTransaction() } } db.inTransaction { delete("hackathon", "name = ?", arrayOf("Pixels Camp")) }
67. inline fun SQLiteDatabase.inTransaction(func: SQLiteDatabase.() -> Unit) { beginTransaction() try { func() setTransactionSuccessful() } finally { endTransaction() } } db.inTransaction { delete("hackathon", "name = ?", arrayOf("Pixels Camp")) }
68. fun Cursor.getStringOrNull(columnName: String): String? { val index = getColumnIndexOrThrow(columnName) return if (isNull(index)) null else getString(index) } fun View.setPaddingTop(top: Int) { setPadding(paddingLeft, top, paddingRight, paddingBottom) } fun View.toBitmap() : Bitmap? { if (width > 0 && height > 0) { val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888) val canvas = Canvas(bitmap) draw(canvas) return bitmap } else { return null } }
69. fun Cursor.getStringOrNull(columnName: String): String? { val index = getColumnIndexOrThrow(columnName) return if (isNull(index)) null else getString(index) } fun View.setPaddingTop(top: Int) { setPadding(paddingLeft, top, paddingRight, paddingBottom) } fun View.toBitmap() : Bitmap? { if (width > 0 && height > 0) { val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888) val canvas = Canvas(bitmap) draw(canvas) return bitmap } else { return null } }
70. fun Cursor.getStringOrNull(columnName: String): String? { val index = getColumnIndexOrThrow(columnName) return if (isNull(index)) null else getString(index) } fun View.setPaddingTop(top: Int) { setPadding(paddingLeft, top, paddingRight, paddingBottom) } fun View.toBitmap() : Bitmap? { if (width > 0 && height > 0) { val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888) val canvas = Canvas(bitmap) draw(canvas) return bitmap } else { return null } }
71. fun Cursor.getStringOrNull(columnName: String): String? { val index = getColumnIndexOrThrow(columnName) return if (isNull(index)) null else getString(index) } fun View.setPaddingTop(top: Int) { setPadding(paddingLeft, top, paddingRight, paddingBottom) } fun View.toBitmap() : Bitmap? { if (width > 0 && height > 0) { val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888) val canvas = Canvas(bitmap) draw(canvas) return bitmap } else { return null } }
72. fun Cursor.getStringOrNull(columnName: String): String? { val index = getColumnIndexOrThrow(columnName) return if (isNull(index)) null else getString(index) } fun View.setPaddingTop(top: Int) { setPadding(paddingLeft, top, paddingRight, paddingBottom) } fun View.toBitmap() : Bitmap? { if (width > 0 && height > 0) { val bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888) val canvas = Canvas(bitmap) draw(canvas) return bitmap } else { return null } }
73. Modern Fast Small Interoperable Kotlin Android APIs
74. Anko?
75. Anko XML is not typesafe nor null-safe XML is parsed at runtime XML makes code reuse hard Kotlin DSL
76. verticalLayout { val name = editText() button("Say Hello") { onClick { toast("Hello, ${name.text}!") } } }
77. override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) verticalLayout { val name = editText() button("Say Hello") { onClick { toast("Hello, ${name.text}!") } } } }
78. fun _LinearLayout.inputField(name: String): TextView { textView("$name:") { textSize = 18f }.lparams { verticalMargin = dip(4) } return editText() } override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) verticalLayout { padding = dip(16) val login = inputField("Username") val email = inputField("E-mail") button("Sign up") { textSize = 14f onClick { login(login.text) } }.lparams { topMargin = dip(8) } } }
79. fun _LinearLayout.inputField(name: String): TextView { textView("$name:") { textSize = 18f }.lparams { verticalMargin = dip(4) } return editText() } override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) verticalLayout { padding = dip(16) val login = inputField("Username") val email = inputField("E-mail") button("Sign up") { textSize = 14f onClick { login(login.text) } }.lparams { topMargin = dip(8) } } }
80. fun _LinearLayout.inputField(name: String): TextView { textView("$name:") { textSize = 18f }.lparams { verticalMargin = dip(4) } return editText() } override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) verticalLayout { padding = dip(16) val login = inputField("Username") val email = inputField("E-mail") button("Sign up") { textSize = 14f onClick { login(login.text) } }.lparams { topMargin = dip(8) } } }
81. Anko DSL More than a DSL
82. Anko Business logic / UI Limited to Java API No theme support in 0.8.3
83. Anko Fast (~2x)
84. Kotlin now Anko maybe
85. @goncalossilva j.mp/100ka-slides Thank you