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A Multiplatform Adventure
workshop edition
@cafonsomota
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Android Dev Lead @WITSoftware
Founder @GDGCoimbra and co-founder @Kotlin_Knights
✍ Author @rwenderlich and @opinioesonline
Podcaster wannabe
Loves travel, photography and running
@cafonsomota
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MATERIALS
speakerdeck.com/cmota/a-multiplatform-adventure
github.com/cmota/kmm-a-multiplatform-adventure
cmota.github.io/kmp-codelabs
IDE’s required
Android Studio
Xcode
@cafonsomota
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@cafonsomota
install KMM plugin on Android Studio
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$ git clone https:!//github.com/cmota/kmm-all-together-now.git
install KMM plugin on Android Studio
github.com/cmota/kmm-all-together-now
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$ git clone https:!//github.com/cmota/kmm-all-together-now.git
AllTogetherNow [kmm-all-together-now/00. Starter Project]
install KMM plugin on Android Studio
github.com/cmota/kmm-all-together-now
open “00. Starter Project”
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$ git clone https:!//github.com/cmota/kmm-all-together-now.git
AllTogetherNow [kmm-all-together-now/00. Starter Project]
install KMM plugin on Android Studio
github.com/cmota/kmm-all-together-now
open “00. Starter Project”
wait for gradle to finish
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xkcd.com/303/
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> Task :shared:cinteropFirebaseFirestoreIos FAILED
2 actionable tasks: 1 executed, 1 up-to-date
xcrun: error: unable to find utility "xcodebuild", not a developer tool or in PATH
Exception in thread "main" org.jetbrains.kotlin.konan.MissingXcodeException: An error occurred during an xcrun
execution. Make sure that Xcode and its command line tools are properly installed.
at org.jetbrains.kotlin.konan.target.CurrentXcode.xcrun(Xcode.kt:77)
at org.jetbrains.kotlin.konan.target.CurrentXcode.access$xcrun(Xcode.kt:45)
at org.jetbrains.kotlin.konan.target.CurrentXcode$version$2.invoke(Xcode.kt:70)
at org.jetbrains.kotlin.konan.target.CurrentXcode$version$2.invoke(Xcode.kt:45)
at kotlin.SynchronizedLazyImpl.getValue(LazyJVM.kt:74)
AllTogetherNow [kmm-all-together-now/00. Starter Project]
install KMM plugin on Android Studio
github.com/cmota/kmm-all-together-now
open “00. Starter Project”
wait for gradle to finish
❌ no Xcode installed
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!/* If you don't have Xcode installed comment this code block!*/
!/* Search for this comment on build.gradle.kts (:shared) and comment all the references to iOS:
* - onPhone
* - cocoa pods
* - iosMain
* - iosTest
* - packForXcode
* - tasks.getByName(“build”)
!*/
AllTogetherNow [kmm-all-together-now/00. Starter Project]
install KMM plugin on Android Studio
github.com/cmota/kmm-all-together-now
open “00. Starter Project”
wait for gradle to finish
comment iOS related blocks on build.gradle.kts (:shared)
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BUILD SUCCESSFUL in 11s
44 actionable tasks: 44 executed
AllTogetherNow [kmm-all-together-now/00. Starter Project]
install KMM plugin on Android Studio
github.com/cmota/kmm-all-together-now
open “00. Starter Project”
wait for gradle to finish
✅ Xcode installed
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iosApp: pod install
install KMM plugin on Android Studio
github.com/cmota/kmm-all-together-now
open “00. Starter Project”
wait for gradle to finish
go to iosApp folder on Terminal and execute “pod install”
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install KMM plugin on Android Studio
github.com/cmota/kmm-all-together-now
open “00. Starter Project”
wait for gradle to finish
go to iosApp folder on Terminal and execute “pod install”
compile and run the app
$ git clone https:!//github.com/cmota/kmm-all-together-now.git
AllTogetherNow [kmm-all-together-now/00. Starter Project]
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@cafonsomota
and now we wait…
(In KMM defense, well we’ve got the FirebaseFirestore lib as a pod)
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dev-reactions/crash-in-production.gif
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A Multiplatform Adventure
A bit of theory…
@cafonsomota
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@cafonsomota
dev-reactions/commitstrip/unrealist-mobile-dev-dream
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2008 2012 2018
2013
2011 2017
2006 2010
2009 2015
* Kotlin Multiplatform
*
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- Smaller team
- Small learning curve for web developers
- Typically half of the cost needed on native
- Less time (working hours) to built
(advantages)
Cross-platform
to test
to fix issues (hopefully not framework specific )
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- Chained to the framework implementation of UI
- new updates from the OS will take time to adopt
- Performance is not the same
- Some native code might need to be written
- OS/ device features are dependent on the fw support
- Dart (flutter) is not widely used language (for now)
- Committed to one framework/ language
(disadvantages)
Cross-platform
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what about Kotlin Multiplatform?
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shares application logic
doesn’t share the application UI
kotlin
multiplatform
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- Chained to the framework implementation of UI
- new updates from the OS will take time to adopt
- Performance is not the same
- Some native code might need to be written
- OS/ device features are dependent on the fw support
- Dart (flutter) is not widely used language (for now)
- Committed to one framework/ language
(disadvantages)
Cross-platform
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- Chained to the framework implementation of UI
- new updates from the OS will take time to adopt
- Performance is not the same
- Some native code might need to be written
- OS/ device features are dependent on the fw support
- Dart (flutter) is not widely used language (for now)
- Committed to one framework/ language
Cross-multiplatform
UI is developed natively
nope, as fast as an update to
the SDK and recompile the apps
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- Chained to the framework implementation of UI
- new updates from the OS will take time to adopt
- Performance is not the same
- Some native code might need to be written
- OS/ device features are dependent on the fw support
- Dart (flutter) is not widely used language (for now)
- Committed to one framework/ language
Cross-multiplatform
nope, as fast as an update to
the SDK and recompile the apps
UI is developed natively
always arguable, but you’re leaving UI to native, so…
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- Chained to the framework implementation of UI
- new updates from the OS will take time to adopt
- Performance is not the same
- Some native code might need to be written
- OS/ device features are dependent on the fw support
- Dart (flutter) is not widely used language (for now)
- Committed to one framework/ language
Cross-multiplatform
nope, as fast as an update to
the SDK and recompile the apps
yes, the UI
UI is developed natively
always arguable, but you’re leaving UI to native, so…
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- Chained to the framework implementation of UI
- new updates from the OS will take time to adopt
- Performance is not the same
- Some native code might need to be written
- OS/ device features are dependent on the fw support
- Dart (flutter) is not widely used language (for now)
- Committed to one framework/ language
Cross-multiplatform
nope, as fast as an update to
the SDK and recompile the apps
yes, the UI
UI is developed natively
you have direct access
to them; although if on
shared module it might
give you extra effort
always arguable, but you’re leaving UI to native, so…
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- Chained to the framework implementation of UI
- new updates from the OS will take time to adopt
- Performance is not the same
- Some native code might need to be written
- OS/ device features are dependent on the fw support
- Dart (flutter) is not widely used language (for now)
- Committed to one framework/ language
Cross-multiplatform
nope, as fast as an update to
the SDK and recompile the apps
yes, the UI
UI is developed natively
kotlin, is one of the most
trending languages nowadays,
with strong community support
always arguable, but you’re leaving UI to native, so…
you have direct access
to them; although if on
shared module it might
give you extra effort
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(advantages)
- Language features
- Kotlin first!
- Low risk
- You decide what’s worth to share across platforms
- Interoperability
- Consistency across platforms
- Strong investment from JetBrains and community support
Kotlin Multiplatform server web native
android desktop
jvmMain jsMain androidMain iosMain macosX64Main
linuxX64Main
mingwX64Main
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- It’s in alpha
- Although we keep seeing new projects in production
- Space was announced during Kotlin Conf 19 (web, desktop and mobile)
(apps in production)
Kotlin Multiplatform
Space
Adapted from: KotlinConf 2019: Opening Keynote by Andrey Breslav
Full KMP
Cash App
Shares:
business logic
Yandex Maps
Shares:
business logic,
wrappers for C++
libraries
PlanGrid Planboard
Workspace
Shares:
business logic,
sync logic,
mgmnt offline data
Shares:
business logic,
networking,
offline caching lyrs
Shares:
business logic
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- Open source
- Concise, safe, interoperable, tool-friendly
- Supported/ used by Google for Android Development
- It’s more than “just for Android”
- Small learning curve involved
- Easily to go from JavaScript/ Swift into Kotlin and back
Kotlin
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var variable = 42
variable = 1
let value = 42
var variable = 42
variable = 1
val value = 42
*adapted from http://nilhcem.com/swift-is-like-kotlin/
(variables and constants)
Kotlin vs Swift
Kotlin
Swift
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fun greet(name: String, day: String): String {
return "Hello $name, today is $day."
}
greet(“World”, “Thursday”)
*updated from http://nilhcem.com/swift-is-like-kotlin/
func greet(_ name: String,_ day: String) -> String {
return "Hello \(name), today is \(day)."
}
greet(“World”, “Thursday”)
Kotlin
Swift
(functions)
Kotlin vs Swift
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K
otlin multiplatform
using kotlin in projects
that target more than
one platform
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network network network
parser parser parser
model model model
presentation presentation presentation
model
parser
network
view
presentation
view view view
presentation presentation presentation
desktop
web
iOS
android
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business logic business logic business logic
model
parser
network
presentation
model
parser
network
presentation
model
parser
network
presentation
model
parser
network
presentation
business logic
view view view view
desktop
web
iOS
android
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android iOS web desktop
model
parser
network
presentation
common
view view view view
java/kotlin objective-c/ swift (kotlin) JS supported in jvm
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dev-reactions/it-works.gif
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but how can different platforms
expect to communicate?
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declared at common module
expect
declared at android module
actual
declared at iOS module
declared at …
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we want a platform-specific value
for the device name
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dev-reactions/god-mode.gif
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- User interface
- RecyclerView and more (Android)
- UITableViewController and more (iOS)
- Multiple network request
- Parse response objects
- Store on local database
- Use system preferences
- Migrate code to Multiplatform
Project structure
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android iOS
Room CoreData
Retrofit Alamofire
GSON/ Moshi JSONSerialization
MVP, MVVM, MVI MVVM, ELM
RxJava RxSwift
Tests Tests
Activity UIViewController
RecyclerView UITableView
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Room CoreData
Retrofit Alamofire
GSON/ Moshi JSONSerialization
MVP, MVVM, MVI MVVM, ELM
RxJava RxSwift
Tests Tests
Activity UIViewController
RecyclerView UITableView
android iOS
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Room CoreData
Retrofit Alamofire
GSON/ Moshi JSONSerialization
MVP, MVVM, MVI MVVM, ELM
RxJava RxSwift
Tests Tests
Activity UIViewController
RecyclerView UITableView
android iOS
Activity UIViewController
RecyclerView UITableView
unnecessary duplication
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SQLDelight
ktor
kotlinx.serialization
MVP
kotlinx.coroutines
kotlin.test
android iOS
Activity UIViewController
RecyclerView UITableView
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multiplatform
ktor
SQLDelight
model
kotlinx.serialization
SendMessages GetConferences
SQLDriver dispatcher
view
presenter
Settings
Firebase
presenter
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@cafonsomota
cmota.github.io/kmp-codelabs/
cmota.github.io/kmp-codelabs
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@cafonsomota
> Configure project :shared
Kotlin Multiplatform Projects are an Alpha feature.
cmota.github.io/kmp-codelabs
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speakerdeck.com/cmota/a-multiplatform-adventure
github.com/cmota/kmm-a-multiplatform-adventure
cmota.github.io/kmp-codelabs
@cafonsomota