Enhanced MotionLayout capabilities such as being able to add multiple listeners and disable touch and await animations using coroutines. Adapted from https://github.com/chrisbanes/tivi/blob/master/common-ui/src/main/java/app/tivi/ui/widget/TiviMotionLayout.kt

EnhancedMotionLayout.kt

class EnhancedMotionLayout @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null,
    defStyleAttr: Int = 0
) : MotionLayout(context, attrs, defStyleAttr) {

    private val listeners = CopyOnWriteArrayList<TransitionListener>()

    fun addTransitionListener(listener: TransitionListener) {
        listeners.addIfAbsent(listener)
    }

    fun removeTransitionListener(listener: TransitionListener) {
        listeners.remove(listener)
    }

    init {
        super.setTransitionListener(object : TransitionListener {
            override fun onTransitionTrigger(motionLayout: MotionLayout, triggerId: Int, positive: Boolean, progress: Float) {
                listeners.forEach {
                    it.onTransitionTrigger(motionLayout, triggerId, positive, progress)
                }
            }

            override fun onTransitionStarted(motionLayout: MotionLayout, startId: Int, endId: Int) {
                listeners.forEach {
                    it.onTransitionStarted(motionLayout, startId, endId)
                }
            }

            override fun onTransitionChange(motionLayout: MotionLayout, startId: Int, endId: Int, progress: Float) {
                listeners.forEach {
                    it.onTransitionChange(motionLayout, startId, endId, progress)
                }
            }

            override fun onTransitionCompleted(motionLayout: MotionLayout, currentId: Int) {
                listeners.forEach {
                    it.onTransitionCompleted(motionLayout, currentId)
                }
            }
        })
    }

    @Deprecated("Use addTransitionListener instead")
    override fun setTransitionListener(listener: TransitionListener) {
        throw IllegalArgumentException("Use addTransitionListener instead")
    }

    /**
     * Whether this MotionLayout should react to nested scrolls and touch events
     */
    var motionEnabled = true

    override fun onStartNestedScroll(child: View, target: View, axes: Int, type: Int): Boolean {
        return motionEnabled && super.onStartNestedScroll(child, target, axes, type)
    }

    override fun onInterceptTouchEvent(event: MotionEvent): Boolean {
        if (event.action == MotionEvent.ACTION_DOWN && !motionEnabled) {
            return false
        }
        return super.onInterceptTouchEvent(event)
    }

    override fun onTouchEvent(event: MotionEvent): Boolean {
        if (event.action == MotionEvent.ACTION_DOWN && !motionEnabled) {
            return false
        }
        return super.onTouchEvent(event)
    }

}

/**
 * Wait for the transition to complete so that the given [transitionId] is fully displayed.
 */
suspend fun EnhancedMotionLayout.transitionTo(@IdRes transitionId: Int) {
    // If we're already at the specified state, return now
    if (currentState == transitionId) return

    suspendCancellableCoroutine<Unit> { cont ->
        val listener = object : TransitionAdapter() {
            override fun onTransitionCompleted(motionLayout: MotionLayout, currentId: Int) {
                if (currentId == transitionId) {
                    removeTransitionListener(this)
                    cont.resume(Unit)
                }
            }
        }
        // If the coroutine is cancelled, remove the listener
        cont.invokeOnCancellation {
            removeTransitionListener(listener)
            // TODO maybe reverse the current transition?
        }
        // And finally add the listener
        addTransitionListener(listener)
        transitionToState(transitionId)
    }
}