updateWith

Updates the UI state with the result of an async operation that performs an action without returning new data.

This function automatically handles the complete async operation lifecycle:

1. Sets loading = true before starting the operation

2. Executes the operation in the ViewModel's coroutine scope

3. Preserves existing data on success (no data changes)

4. Sets error event on failure

5. Sets loading = false when complete

Use this function for async operations that perform actions but don't update screen data:

• Saving/updating data without changing current view

• Deleting items

• Sending analytics events

• Triggering background jobs

• Any operation that returns Result<Unit>

Kotlin Context Parameters

This function uses Kotlin's context parameters feature (context(viewModel: ViewModel)). The ViewModel context provides implicit access to viewModelScope for launching coroutines. You never need to pass the ViewModel explicitly - it's automatically available when called from within a ViewModel.

Usage Example

@HiltViewModel
class SettingsViewModel @Inject constructor(
    private val repository: SettingsRepository
) : ViewModel() {
    private val _uiState = MutableStateFlow(UiState(SettingsScreenData()))
    val uiState = _uiState.asStateFlow()

    fun saveSettings() {
        _uiState.updateWith {
            repository.saveSettings(this) // Returns Result<Unit>
        }
    }

    fun deleteAccount() {
        _uiState.updateWith {
            repository.deleteAccount() // Returns Result<Unit>
        }
    }
}

Difference from updateStateWith

• updateStateWith: For operations that return new data → Updates UiState.data

• updateWith: For operations that return Unit → Preserves UiState.data

Error Handling

• Errors are automatically caught and wrapped in OneTimeEvent

• The error is displayed via StatefulComposable's snackbar mechanism

• Original data is preserved when an error occurs

Duplicate Requests

If called while loading = true, the function returns immediately to prevent duplicate concurrent operations.

Parameters

Type Parameters

See also