KotlinSnipet.ktx

/**
* Source: https://medium.com/androiddevelopers/suspending-over-views-19de9ebd7020
*/
suspend fun Animator.awaitEnd() = suspendCancellableCoroutine<Unit> { cont ->
    // Add an invokeOnCancellation listener. If the coroutine is
    // cancelled, cancel the animation too that will notify
    // listener's onAnimationCancel() function
    cont.invokeOnCancellation { cancel() }

    addListener(object : AnimatorListenerAdapter() {
        private var endedSuccessfully = true

        override fun onAnimationCancel(animation: Animator) {
            // Animator has been cancelled, so flip the success flag
            endedSuccessfully = false
        }

        override fun onAnimationEnd(animation: Animator) {
            // Make sure we remove the listener so we don't keep
            // leak the coroutine continuation
            animation.removeListener(this)

            if (cont.isActive) {
                // If the coroutine is still active...
                if (endedSuccessfully) {
                    // ...and the Animator ended successfully, resume the coroutine
                    cont.resume(Unit)
                } else {
                    // ...and the Animator was cancelled, cancel the coroutine too
                    cont.cancel()
                }
            }
        }
    })
}

/**
* Source: https://medium.com/androiddevelopers/suspending-over-views-19de9ebd7020
*/
suspend fun View.awaitNextLayout() = suspendCancellableCoroutine<Unit> { cont ->
    // This lambda is invoked immediately, allowing us to create
    // a callback/listener

    val listener = object : View.OnLayoutChangeListener {
        override fun onLayoutChange(...) {
            // The next layout has happened!
            // First remove the listener to not leak the coroutine
            view.removeOnLayoutChangeListener(this)
            // Finally resume the continuation, and
            // wake the coroutine up
            cont.resume(Unit)
        }
    }
    // If the coroutine is cancelled, remove the listener
    cont.invokeOnCancellation { removeOnLayoutChangeListener(listener) }
    // And finally add the listener to view
    addOnLayoutChangeListener(listener)

    // The coroutine will now be suspended. It will only be resumed
    // when calling cont.resume() in the listener above
}