collectWithLifecycle

Collects a Flow in a lifecycle-aware manner, automatically canceling when lifecycle stops.

This extension collects the Flow when the lifecycle is at least STARTED and automatically cancels collection when the lifecycle falls below STARTED. This restarts collection on a later STARTED transition. Separately launched upstream jobs have their own lifetimes; this helper does not cancel those jobs. In a Fragment, use viewLifecycleOwner when updating its views.

Illustrative Fragment usage (ViewModel and binding supplied by the caller)

class MyFragment : Fragment() {
    private val viewModel: MyViewModel by viewModels()

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        viewLifecycleOwner.collectWithLifecycle(viewModel.uiState) { state ->
            binding.progressBar.isVisible = state.loading
            binding.errorText.text = state.error
        }
    }
}

Multiple Flows

collectWithLifecycle(viewModel.uiState) { state ->
    updateUI(state)
}

collectWithLifecycle(viewModel.events) { event ->
    handleEvent(event)
}

In Compose (Alternative)

For Composables, use collectAsStateWithLifecycle() instead:

@Composable
fun MyScreen(viewModel: MyViewModel = hiltViewModel()) {
    val uiState by viewModel.uiState.collectAsStateWithLifecycle()
    // Use uiState...
}

Lifecycle Behavior

• Collection starts when lifecycle reaches STARTED

• Collection is cancelled when lifecycle falls below STARTED (e.g., app backgrounded)

• A new collection starts when lifecycle reaches STARTED again

• Collection stops permanently when lifecycle is DESTROYED

Parameters

Type Parameters

See also