fabioCollini

@Composable
fun Calculator(state: CalculatorViewModel) {
    Column {
        TextField(value = state.v1, onValueChange = { state.v1 = it })
        TextField(value = state.v2, onValueChange = { state.v2 = it })
        Text(text = state.result.collectAsState().value)
    }
}

fabioCollini

class CalculatorViewModel : ViewModel() {
    var v1 by mutableStateOf("0")
    var v2 by mutableStateOf("0")
    val result = snapshotFlow { v1 to v2 }.mapLatest {
        sum(it.first, it.second)
    }.stateIn(viewModelScope, SharingStarted.Lazily, "0")
}

fabioCollini

@Composable
fun Calculator(state: CalculatorViewModel) {
    Column {
        TextField(value = state.v1.collectAsState().value, onValueChange = { state.v1.value = it })
        TextField(value = state.v2.collectAsState().value, onValueChange = { state.v2.value = it })
        Text(text = state.result.collectAsState().value)
    }
}

fabioCollini

@Composable
fun CalculatorScreen() {
    val viewModel = viewModel<CalculatorViewModel>()
    Calculator(state = viewModel)
}

fabioCollini

class CalculatorViewModel : ViewModel() {
    var v1 = MutableStateFlow("0")
    var v2 = MutableStateFlow("0")
    val result = v1.combine(v2) { a, b -> a to b}.mapLatest {
        sum(it.first, it.second)
    }.stateIn(viewModelScope, SharingStarted.Lazily, "0")
}

fabioCollini

@Composable
fun Calculator(state: CalculatorState) {
    Column {
        TextField(value = state.v1, onValueChange = { state.v1 = it })
        TextField(value = state.v2, onValueChange = { state.v2 = it })
        Text(text = state.result.collectAsState(initial = "").value)
    }
}

fabioCollini

class CalculatorState {
    var v1 by mutableStateOf("0")
    var v2 by mutableStateOf("0")
    val result = snapshotFlow { v1 to v2 }.mapLatest {
        sum(it.first, it.second) //sum is a suspend method here
    }
}

fabioCollini

@Composable
fun CalculatorScreen {
    val state = remember {
        CalculatorState()
    }
    Calculator(state = state)
}

fabioCollini

class CalculatorState {
    var v1 by mutableStateOf("0")
    var v2 by mutableStateOf("0")
    val result get() = sum(v1, v2)
}

fun sum(v1: String, v2: String) = try {
    (v1.toInt() + v2.toInt()).toString()
} catch (e: NumberFormatException) {
    "Parsing error :("

fabioCollini

@Composable
fun Calculator(state: CalculatorState) {
    Column {
        TextField(value = state.v1, onValueChange = { state.v1 = it })
        TextField(value = state.v2, onValueChange = { state.v2 = it })
        Text(text = state.result)
    }
}