In this tutorial, we will create a simple web UI application using the Compose HTML Library.
You need to have the following software installed before you begin:
- JDK 11 or later
- IntelliJ IDEA Community Edition or Ultimate Edition 2020.2 or later (you can use other editors, but for this tutorial we assume you are using IntelliJ IDEA)
You can create the project by downloading the template here.
If you want to create the project manually, perform the following steps:
- Select
Gradle
on the left menu - Tick
Kotlin DSL build script
- Tick
Kotlin/Multiplatform
pluginManagement {
repositories {
gradlePluginPortal()
maven("https://maven.pkg.jetbrains.space/public/p/compose/dev")
}
}
// Add compose gradle plugin
plugins {
kotlin("multiplatform") version "2.0.20"
id("org.jetbrains.compose") version "1.7.1"
}
// Add maven repositories
repositories {
mavenCentral()
maven("https://maven.pkg.jetbrains.space/public/p/compose/dev")
google()
}
// Enable JS(IR) target and add dependencies
kotlin {
js(IR) {
browser()
binaries.executable()
}
sourceSets {
val jsMain by getting {
dependencies {
implementation(compose.html.core)
implementation(compose.runtime)
}
}
}
}
- src/jsMain/kotlin
- src/jsMain/resources
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Sample</title>
</head>
<body>
<div id="root"></div>
<script src="REPLACE_WITH_YOUR_MODULE_NAME.js"></script>
</body>
</html>
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.getValue
import androidx.compose.runtime.setValue
import androidx.compose.runtime.Composable
import org.jetbrains.compose.web.attributes.*
import org.jetbrains.compose.web.css.*
import org.jetbrains.compose.web.dom.*
import org.jetbrains.compose.web.renderComposable
fun main() {
var count: Int by mutableStateOf(0)
renderComposable(rootElementId = "root") {
Div({ style { padding(25.px) } }) {
Button(attrs = {
onClick { count -= 1 }
}) {
Text("-")
}
Span({ style { padding(15.px) } }) {
Text("$count")
}
Button(attrs = {
onClick { count += 1 }
}) {
Text("+")
}
}
}
}
Use the command line to run:
./gradlew jsBrowserRun
Instead of manually compiling and executing a Kotlin/JS project every time you want to see the changes you made, you can use the continuous compilation mode:
./gradlew jsBrowserRun --continuous
Or run it from the IDE:
The browser will open localhost:8080
:
https://youtrack.jetbrains.com/issue/KT-49124
[webpack-cli] Unable to load '@webpack-cli/serve' command
[webpack-cli] TypeError: options.forEach is not a function
...
There is a temporary workaround:
In build.gradle.kts:
// a temporary workaround for a bug in jsRun invocation - see https://youtrack.jetbrains.com/issue/KT-48273
afterEvaluate {
rootProject.extensions.configure<org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootExtension> {
versions.webpackDevServer.version = "4.0.0"
versions.webpackCli.version = "4.9.0"
}
}