Snackbar

The snackbar component serves as a brief notification that appears at the bottom of the screen. It provides feedback about an operation or action without interrupting the user experience. Snackbars disappear after a few seconds. The user can also dismiss them with an action, such as tapping a button.

Consider these three use cases where you might use a snackbar:

• Action Confirmation: After a user deletes an email or message, a snackbar appears to confirm the action and offer an "Undo" option.
• Network Status: When the app loses its internet connection, a snackbar pops up to note that it is now offline.
• Data Submission: Upon successfully submitting a form or updating settings, a snackbar notes that the change has saved successfully.

Basic example

To implement a snackbar, you first create SnackbarHost, which includes a SnackbarHostState property. SnackbarHostState provides access to the showSnackbar() function which you can use to display your snackbar.

This suspending function requires a CoroutineScope such as with using rememberCoroutineScope — and can be called in response to UI events to show a Snackbar within Scaffold.

val scope = rememberCoroutineScope()
val snackbarHostState = remember { SnackbarHostState() }
Scaffold(
    snackbarHost = {
        SnackbarHost(hostState = snackbarHostState)
    },
    floatingActionButton = {
        ExtendedFloatingActionButton(
            text = { Text("Show snackbar") },
            icon = { Icon(Icons.Filled.Image, contentDescription = "") },
            onClick = {
                scope.launch {
                    snackbarHostState.showSnackbar("Snackbar")
                }
            }
        )
    }
) { contentPadding ->
    // Screen content
}
MaterialLayoutSnippets.kt

Snackbar with action

You can provide an optional action and adjust the duration of the Snackbar. The snackbarHostState.showSnackbar() function accepts additional actionLabel and duration parameters, and returns a SnackbarResult.

val scope = rememberCoroutineScope()
val snackbarHostState = remember { SnackbarHostState() }
Scaffold(
    snackbarHost = {
        SnackbarHost(hostState = snackbarHostState)
    },
    floatingActionButton = {
        ExtendedFloatingActionButton(
            text = { Text("Show snackbar") },
            icon = { Icon(Icons.Filled.Image, contentDescription = "") },
            onClick = {
                scope.launch {
                    val result = snackbarHostState
                        .showSnackbar(
                            message = "Snackbar",
                            actionLabel = "Action",
                            // Defaults to SnackbarDuration.Short
                            duration = SnackbarDuration.Indefinite
                        )
                    when (result) {
                        SnackbarResult.ActionPerformed -> {
                            /* Handle snackbar action performed */
                        }
                        SnackbarResult.Dismissed -> {
                            /* Handle snackbar dismissed */
                        }
                    }
                }
            }
        )
    }
) { contentPadding ->
    // Screen content
}
MaterialLayoutSnippets.kt

You can provide a custom Snackbar with the snackbarHost parameter. See the SnackbarHost API reference docs for more information.

Key points

• actionLabel = "Action": Sets the action button text.
• withDismissAction = true: Provides a cross in the snackbar. Tap it to dismiss the snackbar.
• duration = SnackbarDuration.Indefinite: Keeps the snackbar displayed until the user or program dismisses it.
• SnackbarResult.ActionPerformed: Signifies that the user clicked the snackbar's action button.
• SnackbarResult.Dismissed: Signifies that the user dismissed the snackbar without clicking the action button.