Several View extension functions.

RecyclervViewExt.kt

import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import kotlinx.coroutines.channels.awaitClose
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.callbackFlow
import kotlinx.coroutines.flow.distinctUntilChanged

fun <K : Any> RecyclerView.itemVisibilityFlow(
	itemKey: K,
	getItemKey: (position: Int) -> K?,
): Flow<Boolean> {
	return callbackFlow {
		val scrollListener = object : RecyclerView.OnScrollListener() {
			override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {

				val layoutManager = recyclerView.layoutManager

				check(layoutManager is LinearLayoutManager) {
					"To use RecyclerView.itemVisibilityFlow RecyclerView must have a LinearLayoutManager."
				}

				val firstVisiblePosition = layoutManager.findFirstVisibleItemPosition()
				val lastVisiblePosition = layoutManager.findLastVisibleItemPosition()
				var isVisible = false

				for (position in firstVisiblePosition..lastVisiblePosition) {
					val currentItemKey = getItemKey(position) ?: continue

					isVisible = currentItemKey == itemKey

					if (isVisible) {
						break
					}
				}

				trySend(isVisible)
			}
		}

		addOnScrollListener(scrollListener)

		awaitClose {
			removeOnScrollListener(scrollListener)
		}
	}.distinctUntilChanged()
}

/**
 * Source: https://proandroiddev.com/horizontal-recyclerview-within-viewpager2-1f49f366d54e
 */
fun RecyclerView.avoidConflictsWithHorizontalViewPager() {
	addOnItemTouchListener(
		object : RecyclerView.OnItemTouchListener {
			private var startX = 0f

			override fun onInterceptTouchEvent(
				recyclerView: RecyclerView,
				event: MotionEvent,
			): Boolean =
				when (event.action) {
					MotionEvent.ACTION_DOWN -> {
						startX = event.x
					}
					MotionEvent.ACTION_MOVE -> {
						val isScrollingRight = event.x < startX
						val scrollItemsToRight = isScrollingRight && recyclerView.canScrollHorizontally(1)
						val scrollItemsToLeft = !isScrollingRight && recyclerView.canScrollHorizontally(-1)
						val disallowIntercept = scrollItemsToRight || scrollItemsToLeft
						recyclerView.parent.requestDisallowInterceptTouchEvent(disallowIntercept)
					}
					MotionEvent.ACTION_UP -> {
						startX = 0f
					}
					else -> Unit
				}.let { false }

			override fun onTouchEvent(rv: RecyclerView, e: MotionEvent) = Unit
			override fun onRequestDisallowInterceptTouchEvent(disallowIntercept: Boolean) = Unit
		}
	)
}

suspend fun RecyclerView.awaitScrollState(
	scrollState: Int,
) {
	// If a smooth scroll has just been started, it won't actually start until the next
	// animation frame, so we'll await that first
	awaitAnimationFrame()
	// Now we can check if we're actually idle. If so, return now
	if (this.scrollState == scrollState) return

	callbackFlow<Unit> {
		val scrollListener = object : RecyclerView.OnScrollListener() {
			override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
				if (newState == scrollState) {
					// Make sure we remove the listener so we don't keep leak the
					// coroutine continuation
					recyclerView.removeOnScrollListener(this)
					// Finally, resume the coroutine
					trySend(Unit)
				}
			}
		}

		addOnScrollListener(scrollListener)

		awaitClose {
			removeOnScrollListener(scrollListener)
		}
	}
}

suspend inline fun RecyclerView.awaitScrollEnd() {
	awaitScrollState(RecyclerView.SCROLL_STATE_IDLE)
}

inline val LinearLayoutManager.visibleItemCount: Int
	get() {
		val firstVisiblePosition = findFirstVisibleItemPosition()
		val lastVisiblePosition = findLastVisibleItemPosition()

		return lastVisiblePosition - firstVisiblePosition + 1
	}

inline val RecyclerView.visibleItemCount: Int
	get() {
		val layoutManager = layoutManager

		require(layoutManager is LinearLayoutManager) {
			"To use RecyclerView.visibleItemCount RecyclerView must have a LinearLayoutManager."
		}

		return layoutManager.visibleItemCount
	}

ViewExt.kt

import android.view.View
import kotlinx.coroutines.suspendCancellableCoroutine

// Source: https://github.com/chrisbanes/tivi/blob/ee7c5f9870cb4c5ce0b5c2d2ba18e538cefc1254/common-ui-view/src/main/java/app/tivi/extensions/ViewExtensions.kt

suspend fun View.awaitAnimationFrame() {
	suspendCancellableCoroutine<Unit> { cont ->
		val runnable = Runnable {
			cont.resumeWith(Result.success(Unit))
		}
		// If the coroutine is cancelled, remove the callback
		cont.invokeOnCancellation { removeCallbacks(runnable) }
		// And finally post the runnable
		postOnAnimation(runnable)
	}
}

suspend fun View.awaitPost() {
	suspendCancellableCoroutine<Unit> { cont ->
		val runnable = Runnable {
			cont.resumeWith(Result.success(Unit))
		}
		cont.invokeOnCancellation { removeCallbacks(runnable) }

		post(runnable)
	}
}