mattmook

private val ddMMMMyyyyRegex = "([0-9]{1,2})\\s+([A-Za-z]{3,4})\\s+([0-9]{4})".toRegex()

private val monthMapping = mapOf(
    "Jan" to Month.JANUARY,
    ...
    "Sep" to Month.SEPTEMBER,
    "Sept" to Month.SEPTEMBER,
    ...
    "Dec" to Month.DECEMBER
)

mattmook

public class PostListViewModelStateObject : ObservableObject {

    @Published public private(set) var state: PostListState

    init(viewModel: PostListViewModel) {
        self.state = viewModel.container.stateFlow.value as! PostListState

        (viewModel.container.stateFlow.asPublisher() as AnyPublisher<PostListState, Never>)
                .receive(on: RunLoop.main)
                .assign(to: &$state)

mattmook

import Foundation
import Combine
import shared

public extension Kotlinx_coroutines_coreFlow {
    func asPublisher<T: AnyObject>() -> AnyPublisher<T, Never> {
        (FlowPublisher(flow: self) as FlowPublisher<T>).eraseToAnyPublisher()
    }
}

mattmook

fun Flow<*>.subscribe(onEach: (item: Any) -> Unit, onComplete: () -> Unit, onThrow: (error: Throwable) -> Unit): Job =
    this.onEach { onEach(it as Any) }
        .catch { onThrow(it) }
        .onCompletion { onComplete() }
        .launchIn(CoroutineScope(Job() + Dispatchers.Main))

mattmook

class PostListViewModel(
    private val postRepository: PostRepository,
) : ViewModel(), ContainerHost<PostListState, NavigationEvent> {

    override val container = viewModelScope.container<PostListState, NavigationEvent>(
        initialState = PostListState()
    ) {
        loadOverviews()
    }

mattmook

@Composable
fun Screen() {
    val lazyListState = rememberLazyListState()

    Column {
        AppBar(stringResource(id = R.string.app_name), elevation = lazyListState.elevation)

        LazyColumn(state = lazyListState) {
            ...
        }

mattmook

val lazyListState = rememberLazyListState()
LazyColumn(state = lazyListState) {
    ...
}

mattmook

val LazyListState.elevation: Dp
    get() = if (firstVisibleItemIndex == 0) {
        // For the first element, use the minimum of scroll offset and default elevation
        // i.e. a value between 0 and 4.dp
        minOf(firstVisibleItemScrollOffset.toFloat().dp, AppBarDefaults.TopAppBarElevation)
    } else {
        // If not the first element, always set elevation and show the shadow
        AppBarDefaults.TopAppBarElevation
    }

mattmook

class ShadowScrollBehavior(context: Context, attrs: AttributeSet) : AppBarLayout.ScrollingViewBehavior(context, attrs) {

    @SuppressLint("PrivateResource")
    private val maxElevation = context.resources.getDimensionPixelSize(R.dimen.design_appbar_elevation).toFloat()

    override fun onDependentViewChanged(parent: CoordinatorLayout, child: View, dependency: View):
            Boolean {
        if (dependency is AppBarLayout) {
            when (child) {
                is NestedScrollView -> {

mattmook

lifecycleScope.launch {
    // See https://medium.com/androiddevelopers/a-safer-way-to-collect-flows-from-android-uis-23080b1f8bda    
    lifecycleOwner.lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
        launch { viewModel.container.stateFlow.collect(::reduce)
        launch { viewModel.container.sideEffectFlow.collect(::sideEffect)
    }
}