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Compose Multiplatform

Compose Multiplatform simplifies and accelerates UI and share it between Android, IOS, Desktop and Web.

Experimental targets

iOS is experimental and under development. Use it at your own risk and that explains why you will have some laggy animation with it.

Repositroy

This repository will contain instructions to start your first Compose Multiplatform Project.

Plugin

Install KMM plugin in Android Studio

Instructions

  • Create a new KMM project using the plugin above

Screenshot 2023-02-25 at 6 58 46 PM

Setup Compose for KMM

in your settings.gradle file add the following dependency

pluginManagement {
    repositories {
        google()
        gradlePluginPortal()
        mavenCentral()
        maven("https://maven.pkg.jetbrains.space/public/p/compose/dev") // this one
    }
}

in your build.gradle.kts add compose plugin

plugins {
    //trick: for the same plugin versions in all sub-modules
    id("com.android.application").version("8.0.0-alpha09").apply(false)
    id("com.android.library").version("8.0.0-alpha09").apply(false)
    kotlin("android").version("1.8.0").apply(false)
    kotlin("multiplatform").version("1.8.0").apply(false)
    id("org.jetbrains.compose").version("1.3.0") apply false // this one
}

now inside shared module build.gradle.kts add these two plugins

plugins {
    kotlin("multiplatform")
    id("com.android.library")
    kotlin("native.cocoapods") // this 
    id("org.jetbrains.compose") // and this
}}

in your kotlin block add the following lines

ios()
iosSimulatorArm64()

cocoapods {
    summary = "Some description for the Shared Module"
    homepage = "Link to the Shared Module homepage"
    version = "1.0"
    ios.deploymentTarget = "16.1"
    podfile = project.file("../iosApp/Podfile")
    framework {
        baseName = "shared"
        isStatic = true
    }
}

now BEFORE you sync you need to make sure about the following:

  • Install cocoapods

brew install cocoapods
  • cd to iosApp and init pod
 pod init
  • install your pods
pod install

In sourceSets

    sourceSets {
        val commonMain by getting {
            dependencies {
                api(compose.runtime)
                api(compose.foundation)
                api(compose.material)
            }
        }
        val commonTest by getting {
            dependencies {
                implementation(kotlin("test"))
            }
        }
        val androidMain by getting
        val androidUnitTest by getting
        val iosMain by getting {
            dependsOn(commonMain)
        }
        val iosSimulatorArm64Main by getting {
            dependsOn(iosMain)
        }
    }

and to avoid Compose targets ‘[uikit]’ are experimental and may have bugs! Error add this in gradle.properties

org.jetbrains.compose.experimental.uikit.enabled=true

Sync now !

Let the magic begin

Inside your shared module commonMain directory create your first Composable function to use it for Android and IOS

@Composable
internal fun App(){
    Text(Greeting().greet())
}

In your AndroidMain make main.android class to use your App function

@Composable
fun Application(){
    App()
}

In your IosMain make main.ios class to use your App function

fun MainViewController(): UIViewController =
    Application("Example Application") {
        App()
    }

Now go to AndoroidApp module to use the function we made in main.android class

     Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colors.background
                ) {
                    Application()
                }

Next go to IosApp module to use the function we made in main.ios class

import shared // this important to import don't forget it! 

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        window = UIWindow(frame: UIScreen.main.bounds)
        let mainViewController = Main_iosKt.MainViewController()
        window?.rootViewController = mainViewController
        window?.makeKeyAndVisible()
        return true
    }
}

Run

Add this to solve dependencies conflicts in gradle.properties

kotlin.native.cacheKind=none

now you can run your android normally, for IOS you need to run the following command first

 ./gradlew build
 ./gradlew :shared:linkPodDebugFrameworkIosSimulatorArm64

Now open iosApp.xcworkspace inside xcode and run the app!

Resources

JetBrains Compose

Compose Mutliplatofrom Examples

Happy Kotlin ?!

GitHub

View Github