Pebble.AppFocus

Observe when the watch app gains or loses foreground focus.

Subscribe once and update your model when the user leaves or returns to your app.

import Pebble.AppFocus as AppFocus

type Msg
    = FocusChanged AppFocus.State

subscriptions _ =
    AppFocus.onChange FocusChanged

update msg model =
    case msg of
        FocusChanged AppFocus.InFocus ->
            ( { model | paused = False }, Cmd.none )

        FocusChanged AppFocus.OutOfFocus ->
            ( { model | paused = True }, Cmd.none )

For a runnable example, use the watch-demo-app-focus project template in the IDE.