How to have a toast show on an onClick in a Compose Glance widget?

One of the first things I like to do with any hello world app/UI is to have some sort of popup or toast.

It seems like listeners in Glance are fairly limited to a set of action types. How can display something simple like a toast onClick?

Is the only solution to start a service and Toast in the service itself?

>Solution :

You could use the actionRunCallback and show the toast within the action by switching to the main thread.

Button(
    text = "Show toast",
    onClick = actionRunCallback<ToastAction>()
)

class ToastAction : ActionCallback {
    override suspend fun onRun(context: Context, glanceId: GlanceId, parameters: ActionParameters) {
        Handler(context.mainLooper).post { 
            Toast.makeText(context, "My toast", Toast.LENGTH_SHORT).show()
        }
    }
}

Note: Toast are limited in Android-12 and rather discourage but for a test app might be sufficient.