Homo Kotlin, a brief History of Kotlin in Agoda

Android BKK Conference 2018
Android Night CBA - Vietnam

Presentation developed additionally by :
Verachad Wongsawangtham
Tipatai Puthanukunkit

Transcript

2. HOMO KOTLIN A brief History of Kotlin Development in Agoda
5. COGNITIVE REVOLUTION 70,000 BC
6. .subscribe(result -> { saveId(); }, error -> { displayError(); });
8. *.class Java complier
9. *.dex *.class Java complier application.apk
10. *.dex *.class Java complier Kotlin complier application.apk
11. *.dex *.class Java complier Kotlin complier application.apk :app:compileDebugKotlin :app:compileDebugJavaWithJavac
12. fun String.isThaiCharacter(): Boolean
13. fun String.isThaiCharacter(): Boolean public final class Extension { public static final boolean isThaiCharacter(@NotNull String $var) }
14. data class Player( val id: Int, val name: String, var level: Int)
15. data class Player( val id: Int, val name: String, var level: Int)
16. data class Player( val id: Int, val name: String, var level: Int)
17. data class Player( val id: Int, val name: String, var level: Int)
18. data class Player( val id: Int, val name: String, var level: Int)
19. data class Player( val id: Int, val name: String, var level: Int) public String toString() { return "Player(id=" + this.id + ", name=" + this.name + ", level=" + this.level + ")"; }
20. public static final int USER = 1;
21. public static final int USER = 1; interface Player<in T, out R> { fun name(other: T): String fun upgradePlayer(): R }
22. public static final int USER = 1; sealed class Error { object UserNotFound : Error() object ExpiredSession : Error() } interface Player<in T, out R> { fun name(other: T): String fun upgradePlayer(): R }
23. public static final int USER = 1; sealed class Error { object UserNotFound : Error() object ExpiredSession : Error() } interface Player<in T, out R> { fun name(other: T): String fun upgradePlayer(): R } private inline fun perform
24. AGRICULTURAL REVOLUTION 4000 BC 70,000 BC
25. Why Testing?
26. > 10k Test cases > 1000 ATs Why Testing?
27. • More readable test code • Explore Kotlin features Goals:
28. • More readable test code • Explore Kotlin features Goals:
29. View Actions View Matchers View Assertions
30. open class VActions { fun click() = ViewActions.click() … } open class VAssertions { fun isNotEnabled() = ViewAssertions.matches(not(isEnabled())) fun doesNotExist() = ViewAssertions.doesNotExist() … }
31. fun expectToBeVisible() { interaction(vm.viewPageContent, va.isDisplayed()) }
32. • Lots of interesting features • Still not reach our goals!! What we found so far:
33. • Lots of interesting features • Still not reach our goals!! What we found so far: LET’S EXPLORE MORE!!!
34. High-order functions
35. High-order functions “a function that takes functions as parameters, or returns a function”
36. class HTML() { fun body(Body.() -> Unit) { ... } }
37. class HTML() { fun body(Body.() -> Unit) { ... } } fun html(HTML.() -> Unit) { ... }
38. class HTML() { fun body(Body.() -> Unit) { ... } } fun html(HTML.() -> Unit) { ... } html { body { ... } }
39. So, what can we do about it?
40. fun expectToBeVisible() { interaction(vm.layout, va.isDisplayed()) }
41. fun expectToBeVisible() { screen { layout { isDisplayed() } } } fun expectToBeVisible() { interaction(vm.layout, va.isDisplayed()) }
42. • Start to create essential matchers/actions/assertions • Convert some of our PageObject classes How we start?
43. class OccupancyPageKt { val screen = OccupancyScreen() fun shouldBeVisible() { screen { layout { isDisplayed() } } } fun shouldSeeGuestsAndRoomLabel() { screen { guestAndRoomLabel { isDisplayed() } } }
44. Finally, we share effort to the world!!
45. Our main contributor Ilya Lim Twitter: @S_Alviere
46. A bit of summary
47. A bit of summary • Experiment on non-production codebases
48. A bit of summary • Experiment on non-production codebases • Explore on the field we know best
49. A bit of summary • Experiment on non-production codebases • Explore on the field we know best • Contribute back to community
50. 1500 70,000 BC UNIFICATION ANDROID DEVELOPER 4000 BC
51. What should be a first step?
52. What should be a first step?
53. Why we start with companion app?
54. Why we start with companion app? • Isolate from production code • Make us familiar android environment • Easier to evaluate new idea Image from github.com/artem-zinnatullin/qualitymatters
55. What we found in build process?
56. What we found in build process? • Build time
57. What we found in build process? • Build time -> Not Significant different
58. What we found in build process? • Build time -> Not Significant different • APK Size
59. What we found in build process? • Build time -> Not Significant different • APK Size -> ~400KB Added
60. What we found in build process? • Build time -> Not Significant different • APK Size -> ~400KB Added • Methods Count
61. What we found in build process? • Build time -> Not Significant different • APK Size -> ~400KB Added • Methods Count -> ~2k methods
62. What about Tools?
63. What about Tools? • Jacoco -> Coverage Report • Detekt -> Static Code Analysis
64. Let’s start in production app
65. Let’s start in production app
66. We need a plan!! • Selected team starting to write a new feature with Kotlin.
67. We need a plan!! • Knowledge Sharing for all the teams
68. We need a plan!! • Define code style!!
69. We need a plan!! • Channel to ask questions or suggestions
70. After half a year…
71. After half a year… • Everyone is writing Kotlin now.
72. After half a year… • Everyone is writing Kotlin now. • We still sharing knowledge & Best practices among developers
73. After half a year… • Everyone is writing Kotlin now. • We still sharing knowledge & Best practices among developers • Problems (e.g. code generation coverage)
74. Code Generation Problems data class InstayFeedbackCategoryEntity( val id: Int, val title: String )
75. Code Generation Problems public final class InstayFeedbackCategoryEntity { … public int hashCode() { return this.id * 31 + (this.title != null?this.title.hashCode():0); } public boolean equals(Object var1) { if(this != var1) { if(var1 instanceof InstayFeedbackCategoryEntity) { InstayFeedbackCategoryEntity var2 = (InstayFeedbackCategoryEntity)var1; if(this.id == var2.id && Intrinsics.areEqual(this.title, var2.title)) { return true; } } return false; } else { return true; } } }
76. Solutions https://medium.com/@andrey.fomenkov/kotlin-jacoco-tuning-compiler-to-skip- generated-code-935fcaeaa391
77. 1900s 70,000 BC 4000 BC SCIENTIFIC REVOLUTION PART 4 1500s
78. How we use Kotlin to make Android Development better?
79. Data class
80. @AutoValue public abstract class HotelDetailEntity { public abstract int hotelId(); public abstract String basicInformation(); public abstract List<String> images(); public abstract List<AttractionEntity> attractions(); public abstract List<Integer> facilityIds(); public abstract List<HotelUsefulInformationEntity> usefulInformation(); public abstract List<ReviewEntity> reviews(); public static Builder builder() { return new AutoValue_HotelDetailEntity.Builder(); } @AutoValue.Builder public abstract static class Builder { public abstract HotelDetailEntity.Builder hotelId(int hotelId); public abstract HotelDetailEntity.Builder basicInformation(String basicInformation); public abstract HotelDetailEntity.Builder images(List<String> images); public abstract HotelDetailEntity.Builder attractions(List<AttractionEntity> attractionEntities); public abstract HotelDetailEntity.Builder facilityIds(List<Integer> facilityIds); public abstract HotelDetailEntity.Builder usefulInformation(List<HotelUsefulInformationEntity> usefulInformation); public abstract HotelDetailEntity.Builder reviews(List<ReviewEntity> reviews); public abstract HotelUsefulInformationEntity build(); } }
81. @AutoValue public abstract class HotelDetailEntity { public abstract int hotelId(); public abstract String basicInformation(); public abstract List<String> images(); public abstract List<AttractionEntity> attractions(); public abstract List<Integer> facilityIds(); public abstract List<HotelUsefulInformationEntity> usefulInformation(); public abstract List<ReviewEntity> reviews(); public static Builder builder() { return new AutoValue_HotelDetailEntity.Builder(); } @AutoValue.Builder public abstract static class Builder { public abstract HotelDetailEntity.Builder hotelId(int hotelId); public abstract HotelDetailEntity.Builder basicInformation(String basicInformation); public abstract HotelDetailEntity.Builder images(List<String> images); public abstract HotelDetailEntity.Builder attractions(List<AttractionEntity> attractionEntities); public abstract HotelDetailEntity.Builder facilityIds(List<Integer> facilityIds); public abstract HotelDetailEntity.Builder usefulInformation(List<HotelUsefulInformationEntity> usefulInformation); public abstract HotelDetailEntity.Builder reviews(List<ReviewEntity> reviews); public abstract HotelUsefulInformationEntity build(); } }
82. data class HotelDetailEntity( val hotelId: Int, val basicInformation: BasicInformationEntity, val images: ImagesEntity, val attractions: List<AttractionEntity> val facilityIds: List<Int>, val usefulInformation: List<HotelUsefulInformationEntity>, val reviews: List<ReviewEntity> )
83. Custom View
84. public class CheckInCheckOutDayTimeView extends LinearLayout { private TextView checkInLabel; private TextView checkOutLabel; public CheckInCheckOutDayTimeView(final Context context) { super(context); initView(); } public CheckInCheckOutDayTimeView(final Context context, @Nullable final AttributeSet attrs) { super(context, attrs); initView(); } public CheckInCheckOutDayTimeView(final Context context, @Nullable final AttributeSet attrs, final int defStyleAttr) { super(context, attrs, defStyleAttr); initView(); } @TargetApi(Build.VERSION_CODES.LOLLIPOP) public CheckInCheckOutDayTimeView(final Context context, @Nullable final AttributeSet attrs, final int defStyleAttr, final int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); initView(); } private void initView() { View.inflate(getContext(), R.layout.layout_check_in_check_out_view, this); checkInLabel = findViewById(R.id.check_in_label); checkOutLabel = findViewById(R.id.check_out_label); } }
85. public class CheckInCheckOutDayTimeView extends LinearLayout { private TextView checkInLabel; private TextView checkOutLabel; public CheckInCheckOutDayTimeView(final Context context) { super(context); initView(); } public CheckInCheckOutDayTimeView(final Context context, @Nullable final AttributeSet attrs) { super(context, attrs); initView(); } public CheckInCheckOutDayTimeView(final Context context, @Nullable final AttributeSet attrs, final int defStyleAttr) { super(context, attrs, defStyleAttr); initView(); } @TargetApi(Build.VERSION_CODES.LOLLIPOP) public CheckInCheckOutDayTimeView(final Context context, @Nullable final AttributeSet attrs, final int defStyleAttr, final int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); initView(); } private void initView() { View.inflate(getContext(), R.layout.layout_check_in_check_out_view, this); checkInLabel = findViewById(R.id.check_in_label); checkOutLabel = findViewById(R.id.check_out_label); } }
86. class CheckInCheckOutDayTimeView : LinearLayout { private val checkInLabel by lazy { findViewById<TextView>(R.id.check_in_label) } private val checkOutLabel by lazy { findViewById<TextView>(R.id.check_out_label) } @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0) : super(context, attrs, defStyleAttr) @TargetApi(Build.VERSION_CODES.LOLLIPOP) constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int, defStyleRes: Int) : super(context, attrs, defStyleAttr, defStyleRes) init { View.inflate(context, R.layout.layout_check_in_check_out_view, this) } }
87. Collection Function
88. public void setItems(final List<String> items) { gridLayout.removeAllViews(); for (final String item : items) { if (!item.isEmpty()) { final TextView itemView = createItemView(item); gridLayout.addView(itemView); } } }
89. public void setItems(final List<String> items) { gridLayout.removeAllViews(); for (final String item : items) { if (!item.isEmpty()) { final TextView itemView = createItemView(item); gridLayout.addView(itemView); } } }
90. fun setItems(texts: List<String>) { gridLayout.removeAllViews() texts.asSequence() .filter(String::isNotEmpty) .map(::createItemView) .forEach(gridLayout::addView) }
91. Safe Cast
92. public class SimpleFragment extends Fragment { interface Listener { void showErrorDialog(final Throwable throwable); } public void onError(final Throwable throwable) { final Activity activity = getActivity(); if (activity instanceof Listener) { ((Listener) activity).showErrorDialog(throwable); } } }
93. public class SimpleFragment extends Fragment { interface Listener { void showErrorDialog(final Throwable throwable); } public void onError(final Throwable throwable) { final Activity activity = getActivity(); if (activity instanceof Listener) { ((Listener) activity).showErrorDialog(throwable); } } }
94. class SimpleFragment : Fragment() { interface Listener { fun showErrorDialog(throwable: Throwable) } fun onError(throwable: Throwable) { (activity as? Listener)?.showErrorDialog(throwable) } }
95. Dagger
96. @Inject lateinit var sneakerApi: SneakerApi @field:[Inject Named("layoutId")] @JvmField var layoutId: Int = 0
97. @Module class DataModule { @Provides fun provideSneakerRepository(sneakerApi: SneakerApi) = SneakerRepositoryImpl(sneakerApi) }
98. @Module class DataModule { @Provides fun provideSneakerRepository(sneakerApi: SneakerApi) = SneakerRepositoryImpl(sneakerApi) } @Module class DataModule { @Provides fun provideSneakerRepository(sneakerApi: SneakerApi): SneakerRepository = SneakerRepositoryImpl(sneakerApi) }
99. Nullable from Java class
100. @AutoValue public abstract class HotelDetailEntity { public abstract int hotelId(); public abstract String basicInformation(); public abstract List<String> images(); public abstract List<ReviewEntity> reviews(); }
101. @AutoValue public abstract class HotelDetailEntity { public abstract int hotelId(); public abstract String basicInformation(); public abstract List<String> images(); public abstract List<ReviewEntity> reviews(); }
102. @AutoValue public abstract class HotelDetailEntity { public abstract int hotelId(); @NotNull public abstract String basicInformation(); @NotNull public abstract List<String> images(); @Nullable public abstract List<ReviewEntity> reviews(); }
103. Result • Development is easier, faster and more happy.
104. Result • Development is easier, faster and more happy. • Goodbye Java :P
105. Result • Development is easier, faster and more happy. • Goodbye Java :P • Kotlin forever !!
107. HALL OF FAME https://github.com/agoda-com/fork https://github.com/VerachadW/kraph IVAN BALAKSHA VERACHAD W. BIRTH https://github.com/Judrummer/JxAdapter TIPATAI P. JU https://github.com/andreyfomenkov/kotlin ANDREI FOMENKOV
108. ขอบคุณ THANK YOU! DESIGNED BY NETI SHEVAKIDAKARN