Counter Flutter app

Main.fs

module fsharp.Main

open Flutter.Foundation
open Flutter.Rendering
open Flutter.Widgets
open Flutter.Material

open Elmish
open Elmish.Flutter

type Model = { count: int }

type Msg =
    | Increment
    | Decrement

let init () = { count = 0 }, Cmd.none

let update msg model =
    match msg with
    | Increment -> { model with count = model.count + 1 }, Cmd.none
    | Decrement -> { model with count = model.count - 1 }, Cmd.none

let buttons dispatch : Widget =
    Row(
        mainAxisAlignment = MainAxisAlignment.center,
        children =
            [| MaterialButton(child = Text("Increment"), onPressed = fun () -> Increment |> dispatch)
               MaterialButton(child = Text("Decrement"), onPressed = fun () -> Decrement |> dispatch)
               SizedBox(width = 8) |]
    )

let view model dispatch context : Widget =
    Scaffold(
        appBar = AppBar(title = Text("Hello from F#!")),
        body =
            Center(
                child =
                    Column(
                        mainAxisAlignment = MainAxisAlignment.center,
                        children =
                            [| Text("Count:")
                               Text(model.count |> string)
                               SizedBox(height = 8)
                               buttons dispatch |]
                    )
            )
    )

type MyApp(?key: Key) =
    inherit StatelessWidget(?key = key)

    override _.build(context) =
        MaterialApp(title = "Hello from F#!", home = ElmishWidget.From(init, update, view))

let main () = MyApp() |> runApp