SnapHelper

var snapHelper: LinearSnapHelper = object : LinearSnapHelper() {
        override fun findTargetSnapPosition(layoutManager: RecyclerView.LayoutManager?, velocityX: Int, velocityY: Int): Int {
            val centerView = findSnapView(layoutManager!!) ?: return RecyclerView.NO_POSITION
            val position = layoutManager.getPosition(centerView)
            var targetPosition = -1
            if (layoutManager.canScrollHorizontally()) {
                targetPosition = if (velocityX < 0) {
                    position - 1
                } else {
                    position + 1
                }
            }
            if (layoutManager.canScrollVertically()) {
                targetPosition = if (velocityY < 0) {
                    position - 1
                } else {
                    position + 1
                }
            }
            val firstItem = 0
            val lastItem = layoutManager.itemCount - 1
            targetPosition = Math.min(lastItem, Math.max(targetPosition, firstItem))
            return targetPosition
        }
    }
    
    snapHelper.attachToRecyclerView(recyclerView)

LinearSnapHelper 居中问题