Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Travelling Across Asia - Our Journey from Java ...
Search
Amal Kakaiya
April 23, 2018
Programming
0
32
Travelling Across Asia - Our Journey from Java to Kotlin
Given at Android Makers FR - Paris, 2018
Amal Kakaiya
April 23, 2018
Tweet
Share
More Decks by Amal Kakaiya
See All by Amal Kakaiya
KotlinConf 18 - Learn together. Not the same.
k4kya
0
490
Other Decks in Programming
See All in Programming
ソフトウェア品質を数字で捉える技術。事業成長を支えるシステム品質の マネジメント
takuya542
1
13k
テストから始めるAgentic Coding 〜Claude Codeと共に行うTDD〜 / Agentic Coding starts with testing
rkaga
12
4.5k
システム成長を止めない!本番無停止テーブル移行の全貌
sakawe_ee
1
200
Claude Code + Container Use と Cursor で作る ローカル並列開発環境のススメ / ccc local dev
kaelaela
10
5.2k
10 Costly Database Performance Mistakes (And How To Fix Them)
andyatkinson
0
340
PHPで始める振る舞い駆動開発(Behaviour-Driven Development)
ohmori_yusuke
2
390
すべてのコンテキストを、 ユーザー価値に変える
applism118
3
1.3k
Hypervel - A Coroutine Framework for Laravel Artisans
albertcht
1
130
20250704_教育事業におけるアジャイルなデータ基盤構築
hanon52_
5
790
A2A プロトコルを試してみる
azukiazusa1
2
1.4k
iOS 26にアップデートすると実機でのHot Reloadができない?
umigishiaoi
0
130
Google Agent Development Kit でLINE Botを作ってみた
ymd65536
2
250
Featured
See All Featured
Designing Experiences People Love
moore
142
24k
Practical Tips for Bootstrapping Information Extraction Pipelines
honnibal
PRO
20
1.3k
Refactoring Trust on Your Teams (GOTO; Chicago 2020)
rmw
34
3.1k
Fantastic passwords and where to find them - at NoRuKo
philnash
51
3.3k
RailsConf & Balkan Ruby 2019: The Past, Present, and Future of Rails at GitHub
eileencodes
138
34k
The Power of CSS Pseudo Elements
geoffreycrofte
77
5.9k
How to Ace a Technical Interview
jacobian
278
23k
Being A Developer After 40
akosma
90
590k
Designing for humans not robots
tammielis
253
25k
What’s in a name? Adding method to the madness
productmarketing
PRO
23
3.5k
Build your cross-platform service in a week with App Engine
jlugia
231
18k
Mobile First: as difficult as doing things right
swwweet
223
9.7k
Transcript
TRAVELLING ACROSS ASIA OUR JOURNEY FROM JAVA TO KOTLIN Amal
Kakaiya @K4KYA @DeliverooEng
None
DISCLAIMER: COULD TAKE MORE THAN 20 HOURS
Java Kotlin AutoValue/Lombok Data classes Streams support Standard lib functions
Retrolambda Built in lambda support Butterknife Kotterknife/delegate properties # TravellingAcrossAsia @K4KYA
ADOPTING A NEW LANGUAGE IS A HUGE STEP # TravellingAcrossAsia
@K4KYA
TESTS ARE AN EASY WAY TO GET STARTED # TravellingAcrossAsia
@K4KYA
TESTS ARE AN EASY WAY TO GET STARTED BUT NOT
VERY EXCITING # TravellingAcrossAsia @K4KYA
HOW MUCH COULD WE IMPROVE THE MAIN APP? # TravellingAcrossAsia
@K4KYA
None
DON’T GO ROGUE! # TravellingAcrossAsia @K4KYA
KOTLIN HOUR THE MEETING YOU ACTUALLY WANT TO GO TO
# TravellingAcrossAsia @K4KYA
YOU CAN’T START USING A LANGUAGE WITHOUT EVERYBODY KNOWING IT
# TravellingAcrossAsia @K4KYA
DO WE REALLY WANT TO ADD ANOTHER DEPENDENCY? # TravellingAcrossAsia
@K4KYA
None
# TravellingAcrossAsia @K4KYA
# TravellingAcrossAsia @K4KYA
FIND YOUR OWN PACE # TravellingAcrossAsia @K4KYA
None
CONVERT ALL THE THINGS!! # TravellingAcrossAsia @K4KYA
IT WASN’T A SMOOTH RIDE # TravellingAcrossAsia @K4KYA
LEARN FROM EACH OTHER # TravellingAcrossAsia @K4KYA
WE REVIEW CODE EVERY DAY # TravellingAcrossAsia @K4KYA
# TravellingAcrossAsia @K4KYA
ANDROID STUDIO IS YOUR FRIEND # TravellingAcrossAsia @K4KYA
private fun mapToIds(items: List<Item>): List<String> { val ids = mutableListOf<String>()
for (item in items) { ids.add(item.id) } return ids } # TravellingAcrossAsia @K4KYA
private fun mapToIds(items: List<Item>): List<String> { val ids = items.map
{ it.id } return ids } # TravellingAcrossAsia @K4KYA
private fun mapToIds(items: List<Item>): List<String> { return items.map { it.id
} } # TravellingAcrossAsia @K4KYA
private fun mapToIds(items: List<Item>): List<String> = items.map { it.id }
# TravellingAcrossAsia @K4KYA
WHAT’S THIS CODE DOING? # TravellingAcrossAsia @K4KYA
private final mapToId(Ljava/util/List;)Ljava/ util/List; L0 LINENUMBER 2 L0 ALOAD 1
CHECKCAST java/lang/Iterable ASTORE 2 ———————— 75 more lines ———————— # TravellingAcrossAsia @K4KYA
private final List mapToId(List items) { Iterable $receiver$iv = (Iterable)items;
Collection destination$iv$iv = (Collection)(new ArrayList(CollectionsKt.collectionSizeOrDefault($receiver$ iv, 10))); Iterator var5 = $receiver$iv.iterator(); while(var5.hasNext()) { Object item$iv$iv = var5.next(); Item it = (Item)item$iv$iv; String var12 = it.id; destination$iv$iv.add(var12); } return (List)destination$iv$iv; } # TravellingAcrossAsia @K4KYA
EXPECT THE UNEXPECTED # TravellingAcrossAsia @K4KYA
val extraOptions = items .map { "Item $it" } .takeIf
{ showExtraOptions } # TravellingAcrossAsia @K4KYA
Iterable $receiver$iv = (Iterable)items; Collection $receiver$iv = (Collection)(new ArrayList(CollectionsKt.collectionSizeOrDefault($receiver$iv, 10)));
Iterator var8 = $receiver$iv.iterator(); while(var8.hasNext()) { Object item$iv$iv = var8.next(); String it = (String)item$iv$iv; String var17 = "Item " + it; $receiver$iv.add(var17); } List var10000 = (List)$receiver$iv; List extraOptions = showExtraOptions ? var10000 : null; # TravellingAcrossAsia @K4KYA
Iterable $receiver$iv = (Iterable)items; Collection $receiver$iv = (Collection)(new ArrayList(CollectionsKt.collectionSizeOrDefault($receiver$iv, 10)));
Iterator var8 = $receiver$iv.iterator(); while(var8.hasNext()) { Object item$iv$iv = var8.next(); String it = (String)item$iv$iv; String var17 = "Item " + it; $receiver$iv.add(var17); } List var10000 = (List)$receiver$iv; List extraOptions = showExtraOptions ? var10000 : null; # TravellingAcrossAsia @K4KYA
val extraOptions = if (showExtraOptions) items .map { "Item $it"
} else null # TravellingAcrossAsia @K4KYA
CONVERTING CODE # TravellingAcrossAsia @K4KYA
CONVERTING CODE # TravellingAcrossAsia @K4KYA
CONVERTING CODE # TravellingAcrossAsia @K4KYA
CONVERTING CODE ⌘⌥⇧K Ctrl+Alt+⇧+K # TravellingAcrossAsia @K4KYA
CONVERTING CODE # TravellingAcrossAsia @K4KYA
CONVERTING CODE # TravellingAcrossAsia @K4KYA
CONVERTING CODE # TravellingAcrossAsia @K4KYA
CONVERSION CREEP # TravellingAcrossAsia @K4KYA
NULLPOINTEREXCEPTION # TravellingAcrossAsia @K4KYA
NULLPOINTEREXCEPTION # TravellingAcrossAsia @K4KYA
KOTLINNULLPOINTEREXCEPTION # TravellingAcrossAsia @K4KYA
CONSIDER NULLABILITY WHEN IMPLEMENTING A JAVA INTERFACE private val passwordActionListener
= TextView.OnEditorActionListener { _: TextView, _: Int, _: KeyEvent -> login(password()) } # TravellingAcrossAsia @K4KYA
CONSIDER NULLABILITY WHEN IMPLEMENTING A JAVA INTERFACE private val passwordActionListener
= TextView.OnEditorActionListener { _: TextView, _: Int, _: KeyEvent -> login(password()) } # TravellingAcrossAsia @K4KYA
CONSIDER NULLABILITY WHEN IMPLEMENTING A JAVA INTERFACE private val passwordActionListener
= TextView.OnEditorActionListener { _: TextView, _: Int, _: KeyEvent -> login(password()) } # TravellingAcrossAsia @K4KYA
CONSIDER NULLABILITY WHEN IMPLEMENTING A JAVA INTERFACE private val passwordActionListener
= TextView.OnEditorActionListener { _: TextView, _: Int, _: KeyEvent -> login(password()) } # TravellingAcrossAsia @K4KYA
CONSIDER NULLABILITY WHEN IMPLEMENTING A JAVA INTERFACE private val passwordActionListener
= TextView.OnEditorActionListener { _: TextView, _: Int, _: KeyEvent? -> login(password()) } # TravellingAcrossAsia @K4KYA
CONSIDER NULLABILITY WHEN IMPLEMENTING A JAVA INTERFACE private val passwordActionListener
= TextView.OnEditorActionListener { _: TextView, _: Int, _: KeyEvent? -> login(password()) } # TravellingAcrossAsia @K4KYA
CONVERTING CODE class VerifyActivity: BaseActivity<VerifyPresenter>, VerifyScreen { override val message:
String = getString(R.string.verify_error) # TravellingAcrossAsia @K4KYA
CONVERTING CODE class VerifyActivity: BaseActivity<VerifyPresenter>, VerifyScreen { override val message:
String get() = getString(R.string.verify_error) # TravellingAcrossAsia @K4KYA
USE VERSION CONTROL EFFECTIVELY # TravellingAcrossAsia @K4KYA
USE VERSION CONTROL EFFECTIVELY AND YOUR TEAM WILL ❤ YOU
# TravellingAcrossAsia @K4KYA
VERSION HISTORY # TravellingAcrossAsia @K4KYA
VERSION CONTROL CONVERSION AS ONE COMMIT # TravellingAcrossAsia @K4KYA
VERSION CONTROL MERGE CONVERSIONS QUICKLY # TravellingAcrossAsia @K4KYA
VERSION CONTROL # TravellingAcrossAsia @K4KYA
VERSION CONTROL SHARE WHAT YOU LEARNED # TravellingAcrossAsia @K4KYA
SHARE WHAT YOU LEARNED VERSION CONTROL # TravellingAcrossAsia @K4KYA
SHARE WHAT YOU LEARNED VERSION CONTROL # TravellingAcrossAsia @K4KYA
VERSION CONTROL LEAVE IN RETURN TYPES WHEN IT MAKES SENSE
# TravellingAcrossAsia @K4KYA
VERSION CONTROL private fun showPrompt(confirmed: Boolean) = zip(flipper().confirmDrinkingAgeEnabled(), just(confirmed) {
enabled, confirmed -> enabled && (!confirmed) } # TravellingAcrossAsia @K4KYA
VERSION CONTROL private fun showPrompt(confirmed: Boolean): Observable<Boolean> = zip(flipper().confirmDrinkingAgeEnabled(), just(confirmed)
{ enabled, confirmed -> enabled && (!confirmed) } # TravellingAcrossAsia @K4KYA
# TravellingAcrossAsia @K4KYA
ANDROIDANNOTATIONS AUTOVALUE BUTTERKNIFE LOMBOK DAGGER CUSTOM ANNOTATION PROCESSOR # TravellingAcrossAsia
@K4KYA
KAPT KAY - AY - PEE - TEE # TravellingAcrossAsia
@K4KYA
KAPT VS LOMBOK A TRUE STORY # TravellingAcrossAsia @K4KYA
KAPT VS LOMBOK A TRUE STORY # TravellingAcrossAsia @K4KYA
WHAT WOULD WE CHANGE? # TravellingAcrossAsia @K4KYA
CONVERT UTIL CLASSES EARLY # TravellingAcrossAsia @K4KYA
@file:JvmName(“ViewUtils") @JvmName("showView") fun View.show(visible: Boolean) { visibility = if (visible)
VISIBLE else GONE } # TravellingAcrossAsia @K4KYA
DO WHAT WORKS FOR YOUR TEAM # TravellingAcrossAsia @K4KYA
None
THANK YOU WE’RE HIRING Amal Kakaiya @K4KYA