@Composable
private fun MyScreenContent(
uiState: MyUiState,
onToggleClicked: (Boolean) -> Unit
) {
Column {
if (uiState.error != null) {
ErrorMessageCard(message = uiState.error.message ?: "Unknown error")
}
ToggleButton(uiState.isToggleOn) { toggleValue ->
onToggleClicked(toggleValue)
}
}
}
@Composable
fun ErrorMessageCard(
message: String,
contentPadding: Dp = 8.dp,
icon: ImageVector = Icons.Default.Error,
color: Color = MaterialTheme.colors.error
) {
Card(
modifier = Modifier
.fillMaxWidth()
) {
Row(
modifier = Modifier.padding(contentPadding),
verticalAlignment = Alignment.CenterVertically
) {
Image(
imageVector = icon,
contentDescription = null,
colorFilter = ColorFilter.tint(color)
)
Text(
modifier = Modifier.padding(8.dp),
text = message,
color = color
)
}
}
}
@Composable
private fun ToggleButton(
isOn: Boolean,
onClicked: (Boolean) -> Unit
) {
Button(onClick = { onClicked(!isOn) }) {
Text(text = if (isOn) "Off" else "On")
}
}
class MyViewModel (private val repository: MyRepository): ViewModel() {
var uiState by mutableStateOf(MyUiState())
private set
fun onToggleClicked(toggleValue: Boolean) {
viewModelScope.launch {
repository.updateToggle(toggleValue)
.onFailure { th ->
uiState = uiState.copy(error = th)
}
.onSuccess {
uiState = uiState.copy(isToggleOn = true)
}
}
}
}
data class MyUiState(
val error: Throwable? = null,
val isToggleOn: Boolean = false
)
class MyRepository {
suspend fun updateToggle(value: Boolean): Result<Boolean> = withContext(Dispatchers.IO) {
Result.success(true)
}
}
