Android Basics: Introduction to Coroutines in Android Studio

[ZanzibarNuclear]

I am on the starter branch. RaceTracker runs right away, and the Start/Pause button does not do anything.

[yuuk]

Here is my workaround

@Composable
fun RaceTrackerApp() {
    val playerOne = remember {
        RaceParticipant(name = "Player 1", progressIncrement = 1)
    }
    val playerTwo = remember {
        RaceParticipant(name = "Player 2", progressIncrement = 2)
    }
    var raceInProgress by remember { mutableStateOf(false) }

    val scope = rememberCoroutineScope()
    var playerOneTask by remember { mutableStateOf<Job?>(null) }
    var playerTwoTask by remember { mutableStateOf<Job?>(null) }

    // trigger button click event
    val onRunStateChange = { status: Boolean ->
        raceInProgress = status
        // start
        if (status) {
            scope.launch {
                coroutineScope {
                    playerOneTask = launch { playerOne.run() }
                    playerTwoTask = launch { playerTwo.run() }
                }
                raceInProgress = false
            }
        }
        // pause
        if (!status) {
            playerOneTask?.cancel()
            playerTwoTask?.cancel()
        }
    }

    RaceTrackerScreen(
        playerOne = playerOne,
        playerTwo = playerTwo,
        isRunning = raceInProgress,
        onRunStateChange = onRunStateChange,
        modifier = Modifier
            .statusBarsPadding()
            .fillMaxSize()
            .verticalScroll(rememberScrollState())
            .safeDrawingPadding()
            .padding(horizontal = dimensionResource(R.dimen.padding_medium)),
    )
}