Kotlin Multiplatform Help

Tray and notifications

In Compose Multiplatform for desktop, you can add an application icon to the system tray and send system notifications through it.

System tray

Use the Tray() composable to add an application icon to the system tray. Tray() is available in the scope of the application() function, so it can be called next to the application windows or on its own.

The Tray() composable has the following parameters:

  • icon – the Painter that draws the tray icon.

  • menu – the contents of the tray menu. The menu opens on a right-click on Windows and on a left-click on macOS. If you don't add any items, the menu doesn't appear.

  • state – the TrayState used to send notifications.

  • tooltip – the hint shown when the user hovers over the icon.

  • onAction – the action triggered by clicking the icon: a double click on Windows and a right-click on macOS.

The following example creates an application icon in the tray with three menu items:

  • Increment value changes the state shown in the window.

  • Send notification sends a system notification.

  • Exit closes the application.

import androidx.compose.foundation.layout.Box import androidx.compose.foundation.layout.fillMaxSize import androidx.compose.material.Text import androidx.compose.runtime.getValue import androidx.compose.runtime.mutableStateOf import androidx.compose.runtime.remember import androidx.compose.runtime.setValue import androidx.compose.ui.Alignment import androidx.compose.ui.Modifier import androidx.compose.ui.geometry.Offset import androidx.compose.ui.geometry.Size import androidx.compose.ui.graphics.Color import androidx.compose.ui.graphics.drawscope.DrawScope import androidx.compose.ui.graphics.painter.Painter import androidx.compose.ui.window.Tray import androidx.compose.ui.window.Window import androidx.compose.ui.window.application import androidx.compose.ui.window.rememberNotification import androidx.compose.ui.window.rememberTrayState fun main() = application { var count by remember { mutableStateOf(0) } var isOpen by remember { mutableStateOf(true) } if (isOpen) { val trayState = rememberTrayState() val notification = rememberNotification("Notification", "Message from MyApp!") Tray( state = trayState, icon = TrayIcon, menu = { Item( "Increment value", onClick = { count++ } ) Item( "Send notification", onClick = { trayState.sendNotification(notification) } ) Item( "Exit", onClick = { isOpen = false } ) } ) Window( onCloseRequest = { isOpen = false }, icon = MyAppIcon ) { // Window content: Box( modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center ) { Text(text = "Value: $count") } } } } object MyAppIcon : Painter() { override val intrinsicSize = Size(256f, 256f) override fun DrawScope.onDraw() { drawOval(Color.Green, Offset(size.width / 4, 0f), Size(size.width / 2f, size.height)) drawOval(Color.Blue, Offset(0f, size.height / 4), Size(size.width, size.height / 2f)) drawOval(Color.Red, Offset(size.width / 4, size.height / 4), Size(size.width / 2f, size.height / 2f)) } } object TrayIcon : Painter() { override val intrinsicSize = Size(256f, 256f) override fun DrawScope.onDraw() { drawOval(Color(0xFFFFA500)) } }
Tray menu and notification

Not every desktop environment has a system tray. If the platform doesn't support one, Tray() outputs an error to the standard error stream instead of throwing an exception. Check the isTraySupported property before you show tray-related options in your application.

Tray without a window

An application doesn't need a window to have a tray icon. If only the Tray() function is called, the application runs entirely in the system tray:

import androidx.compose.ui.geometry.Size import androidx.compose.ui.graphics.Color import androidx.compose.ui.graphics.drawscope.DrawScope import androidx.compose.ui.graphics.painter.Painter import androidx.compose.ui.window.Tray import androidx.compose.ui.window.application fun main() = application { Tray( icon = TrayIcon, menu = { Item( "Exit", onClick = ::exitApplication ) } ) } object TrayIcon : Painter() { override val intrinsicSize = Size(256f, 256f) override fun DrawScope.onDraw() { drawOval(Color(0xFFFFA500)) } }

Because there is no window to close, exitApplication() should be called from a menu item.

Notifications

To send a system notification, create it with rememberNotification() and pass it to TrayState.sendNotification(), as the system tray example does. Notifications are delivered through the TrayState passed to a Tray() composable. If the state isn't attached to a tray, the notification is lost.

A notification consists of a title, a message, and a type, which defines the icon and the sound of the notification. The available types are None (the default option), Info, Warning, and Error.

The specific assets used for the icon and the sound depend on the platform.

What's next

18 August 2026
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