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Multiplatform Kotlin(?)
Kotlin Developers Meetup
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About Me
● Matthew Vern / Panini
● Twitter: @callipan Github: panpanini
● Mercari, Inc
● Android Engineer (US)
● [email protected]
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About Me
● Matthew Vern / Panini
● Twitter: @callipan Github: panpanini
● Mercari, Inc
● Android Engineer (US)
● [email protected]
● React Native Engineer??
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React Native
● Build native mobile apps using JavaScript and React
● “Write Once, Run Anywhere”
● Works both on Android & iOS
● Hot reload
● Interfaces with native Kotlin/Swift code
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React Native @ Mercari US
● Used in Profile & Chat screens
● Great for simple screens
● Easy feature parity between platforms
● But...
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I wanna write Kotlin
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Kotlin.js
● Transpiles Kotlin to JavaScript
● Kotlin-react https://github.com/JetBrains/create-react-kotlin-app
●
● Kotlin-React-Native?
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Kotlin React Native
● Create Kotlin JS project inside
ReactNative project
● Link React Native JS to Kotlin JS output
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Kotlin React Native
● Create wrapper for React Native JS
● @JsModule
● external
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Kotlin React Native
● React has a lot of ceremony to create
components
● Abstract as much away with DSL
● Makes UI code much cleaner
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Kotlin React Native
● React has a lot of ceremony to create
components
● Abstract as much away with DSL
● Makes UI code much cleaner
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Hot Reload
● “Keep the app running and to inject new
versions of the files that you edited at
runtime”
● Kotlin has to be compiled though...
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Gradle Continuous Build
https://blog.gradle.org/introducing-continuous-
build
● “As of 2.5, Gradle supports continuous build
execution, which will automatically
re-execute builds when changes are
detected to its inputs.”
● Anytime a file is changed, gradle will rerun
the task
● Hot reload!
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Summary
● We can write React Native in Kotlin!
● Supports Hot Reloading
● Kotlin DSL makes building UI easy
● Can run same code on Android & iOS
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Summary
● The Kotlin we write is 90% JavaScript..
● dynamic
● Lots of boilerplate code
● Very little documentation
● Lets just use Kotlin multiplatform instead