안드로이드로 코틀린을 개발하기 위한 가장 기본적인 내용을 정리하였습니다.

1. KOTLIN으로 안드로이드 개발
TAEHWAN

2. KOTLIN
저는
http://thdev.tech/
http://thdev.net
4년차 안드로이드 개발자

3. JetBrains 개발
JVM위에서 동작하는 정적 언어
100% interoperable with Java

4. KOTLIN
KOTLIN??
Null Safety(http://thdev.tech/kotlin/2016/08/04/Kotlin-Null-Safety.html)
DTO(Data Transfer Object)
Lambdas and Stream
Infix notation

5. KOTLIN
ANDROID STUDIO KOTLIN INSTALL

6. KOTLIN
ANDROID STUDIO KOTLIN INSTALL

7. KOTLIN
CONVERT JAVA FILE TO KOTLIN FILE

8. KOTLIN
KOTLIN DEPENDENCIES
buildscript {
ext.kotlin_version = '1.0.3'
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}
}
apply plugin: ‘kotlin-android’
dependencies {
compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
}

9. KOTLIN
KOTLIN DEPENDENCIES
buildscript {
ext.kotlin_version = '1.0.3'
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}
}
apply plugin: ‘kotlin-android’
dependencies {
compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
}

10. KOTLIN
KOTLIN DEPENDENCIES
buildscript {
ext.kotlin_version = '1.0.3'
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}
}
apply plugin: ‘kotlin-android’
dependencies {
compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
}

11. KOTLIN
KOTLIN 개발 폴더
android {
sourceSets {
main.java.srcDirs += 'src/main/kotlin'
}
}

12. KOTLIN
KOTLIN 개발 폴더
android {
sourceSets {
main.java.srcDirs += 'src/main/kotlin'
}
}

13. KOTLIN
KOTLIN 주요 코드
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action”, Snackbar.LENGTH_LONG).setAction("Action", null).show();
}
});
}
}

14. KOTLIN
KOTLIN 주요 코드
class KotlinActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
val fab = findViewById(R.id.fab) as FloatingActionButton
fab.setOnClickListener {
view -> Snackbar.make(view, "Replace with your own action”, Snackbar.LENGTH_LONG)
.setAction("Action", null).show() }
}
}

15. class KotlinActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
val fab = findViewById(R.id.fab) as FloatingActionButton
fab.setOnClickListener {
view -> Snackbar.make(view, "Replace with your own action”, Snackbar.LENGTH_LONG)
.setAction("Action", null).show() }
}
}
KOTLIN
KOTLIN 주요 코드
Java : onClick(View view) {}
Kotlin Lambda : { view -> }

16. KOTLIN
KOTLIN VALUE
val : Read-only
var : Read/Write

17. KOTLIN
KOTLIN VALUE
val : Read-only
var : Read/Write

18. KOTLIN
KOTLIN VALUE
val : Read-only
var : Read/Write

19. KOTLIN
KOTLIN VALUE
val : Read-only
var : Read/Write

20. KOTLIN
KOTLIN VALUE
val : Read-only
var : Read/Write

21. KOTLIN
KOTLIN VALUE
val : Read-only
var : Read/Write

22. KOTLIN
KOTLIN CLASS

23. KOTLIN
KOTLIN CLASS

24. KOTLIN
KOTLIN CLASS

25. KOTLIN
KOTLIN NULL SAFETY

26. KOTLIN
KOTLIN NULL SAFETY

27. KOTLIN
KOTLIN NULL SAFETY

28. KOTLIN
KOTLIN NULL SAFETY

29. KOTLIN
KOTLIN NULL SAFETY

30. KOTLIN
KOTLIN NULL SAFETY

31. KOTLIN
KOTLIN NULL SAFETY

32. KOTLIN
KOTLIN NULL SAFETY
nullValue = null
return null

33. KOTLIN
KOTLIN NULL SAFETY
nullValue = null
return null
nullValue = “abc”
return 3

34. KOTLIN
KOTLIN NULL SAFETY

35. KOTLIN
DTOS(DATA TRANSFER OBJECT)
public class Sample() {
private String name;
private String email;
public Sample(String name, String email) {
this.name = name;
this.email = email;
}
// 생략…
}
JAVA

36. KOTLIN
DTOS(DATA TRANSFER OBJECT)
public class Sample() {
private String name;
private String email;
public Sample(String name, String email) {
this.name = name;
this.email = email;
}
// 생략…
}
data class Sample(var name: String, var email: String)
JAVA Kotlin

37. KOTLIN
DTOS(DATA TRANSFER OBJECT)
data class Sample(var name: String, var email: String)
Kotlin
JAVA 접근시

38. KOTLIN
DTOS(DATA TRANSFER OBJECT)
data class Sample(var name: String, var email: String)
Kotlin
JAVA 접근시
Kotlin 접근시

39. KOTLIN
LAMBDAS
Java
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
view.setAlpha(0.5f);
}
});

40. KOTLIN
LAMBDAS
Java
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
view.setAlpha(0.5f);
}
});
button.setOnClickListener {
view -> view.alpha = 0.5f
}
kotlin

41. KOTLIN
LAMBDAS
Java
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
view.setAlpha(0.5f);
}
});
button.setOnClickListener {
view -> view.alpha = 0.5f
}
kotlin
button.setOnClickListener {
it.alpha = 0.5f
}

42. KOTLIN
STREAM
Java
for (Integer integer : list) {
if (integer > 5) {
integer *= 2;
Log.e("TAG", "Index " + integer);
}
}

43. KOTLIN
STREAM
Java
for (Integer integer : list) {
if (integer > 5) {
integer *= 2;
Log.e("TAG", "Index " + integer);
}
}
list.filter { it > 5 }.map { Log.d("TAG", "index " + (it * 2)) }
kotlin

44. KOTLIN
INFIX NOTATION(중위 표기법)
fun Int.max(x: Int): Int = if (this > x) this else x
1.max(15)

45. KOTLIN
INFIX NOTATION(중위 표기법)
fun Int.max(x: Int): Int = if (this > x) this else x
1.max(15)
infix fun Int.max(x: Int): Int = if (this > x) this else x
1 max 15
변수가 1개일 경우

46. KOTLIN
KOTLIN PROJECT
https://github.com/taehwandev/Android-BlogExample/tree/master/kotlin-example-01
Kotlin
Glide
Retrofit
RxJava

47. DOCUMENT
코틀린 자료들
(Kotlin 문서) https://kotlinlang.org/docs/reference
(Kotlin 자료들) http://thdev.tech/categories.html#Kotlin-ref
(kotlin 샘플) https://github.com/taehwandev/Android-
BlogExample/tree/master/kotlin-example-01
(커니 - let, apply, run, with)
http://kunny.github.io/lecture/kotlin/2016/07/06/kotlin_let_apply_run_with/
(SeongUg Steve Jung - 고차함수) https://medium.com/@jsuch2362/higher-
order-function-in-kotlin-88bb72563f65#.blcnihrrh
(Kotlin weekly) http://100androidquestionsandanswers.us12.list-
manage1.com/subscribe?u=f39692e245b94f7fb693b6d82&id=93b2272cb6

48. THE END…