Compose-facing toast API delivering native-backed transient overlays via a dedicated window when needed; remains visible across navigation and dialogs, lightweight with no extra runtime dependencies.
A tiny Kotlin Multiplatform (KMP) toast library for Compose Multiplatform (Android + iOS).
iOS has no native toast. This library fills that gap: on iOS it renders a transient
overlay in a dedicated UIWindow above normal app content, with the window configured
not to receive touch events. On Android it delegates to the native
android.widget.Toast.
Some KMP toast implementations draw the toast inside the Compose tree
(a Popup/overlay). That ties the toast to the composition: it may be covered by native
dialogs, and navigation behavior depends on where the overlay is hosted.
CMPToaster takes a different route. The API is Compose-friendly (rememberToast()), but the
toast itself is rendered natively:
UIWindow at UIWindowLevelAlert + 1. So it:
In short: a Kotlin Multiplatform toast with a Compose-facing API and platform-backed presentation.
Note: the iOS overlay is positioned near the bottom safe area and is not intended to cover the software keyboard. Android keyboard behavior is handled by the native platform toast.
CMPToaster is published to Maven Central. Make sure mavenCentral() is in your
repositories, then add the dependency to your shared module.
// settings.gradle.kts
dependencyResolutionManagement {
repositories {
mavenCentral()
}
}
// build.gradle.kts (your shared module)
kotlin {
sourceSets {
commonMain.dependencies {
implementation("com.masaibar:cmp-toaster:1.0.0")
}
}
}
import androidx.compose.material3.Button
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import com.masaibar.cmptoaster.ToastDuration
import com.masaibar.cmptoaster.rememberToast
@Composable
fun Demo() {
val toast = rememberToast()
Button(onClick = { toast.show("This is a short toast") }) {
Text("Short toast")
}
Button(onClick = { toast.show(, ToastDuration.LONG) }) {
Text()
}
}
That's the whole API:
expect class Toast {
fun show(
message: String,
duration: ToastDuration = ToastDuration.SHORT
)
}
enum class ToastDuration { SHORT, LONG }
@Composable
expect fun rememberToast(): Toast
| Duration | Android | iOS |
|---|---|---|
SHORT | LENGTH_SHORT |
To build the library and run the sample:
The published artifact was built with Kotlin 2.1.21 and Compose Multiplatform 1.8.2. Consumer projects should use compatible Kotlin and Compose Multiplatform versions.
| Android | iOS |
|---|---|
 |  |
A runnable Compose Multiplatform sample lives in sample/ (shared UI), with an
Android app and an iOS app in iosApp/. It includes:
AlertDialog is openRun it:
sample configurationiosApp/iosApp.xcodeproj in Xcode and run on a simulatorandroid (minSdk 29)iosArm64, iosSimulatorArm64./gradlew :toast:assemble # Android
./gradlew :toast:compileKotlinIosSimulatorArm64 # iOS (fast check)
| App | Links | |
|---|---|---|
 | AdMonitor - Dashboard for AdMob | Google Play / App Store |
Using CMPToaster in your app? Feel free to open a PR to add it here!
MIT © masaibar
android.widget.Toast.| ~2.0s |
LONG | LENGTH_LONG | ~3.5s |
| Tool | Version |
|---|
| JDK | 17 |
| Gradle | 8.11.1 (bundled via wrapper) |
| Android Gradle Plugin | 8.7.3 |
| Android Studio | Ladybug (2024.2.1) |
| Kotlin | 2.1.21 |
| Compose Multiplatform | 1.8.2 |
Android compileSdk / minSdk | 35 / 29 |
| Xcode (for iOS) | 16.x |
| iOS deployment target | 15.0 |
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