recyclerView.addItemDecoration(SpaceItemDecoration(8.dp))

class ItemAdapter : PagingBindingAdapter<NumberItem, NumberItemBindingHolder, NumberViewBinding>(::NumberItemBindingHolder), StickySupport {
    /** 如果某个Position上的Item需要显示悬浮视图，则返回true */
    override fun isSticky(position: Int): Boolean {
        val previous = (position - 1).toString()
        val current = position.toString()
        return position == 0 || current.length > 1 && current.first() != previous.first()
    }

    /** 根据position创建要显示的悬浮视图 */
    override fun createStickyView(position: Int, parent: ViewGroup): View {
        val textView = TextView(parent.context)
        val itemString = position.toString()
        textView.text = if (itemString.length == 1) "0" else itemString.first().toString()
        textView.setPadding(24)
        val typedValue = TypedValue()
        parent.context.theme.resolveAttribute(R.attr.colorSecondary, typedValue, true)
        textView.setBackgroundColor(typedValue.data)
        return textView
    }
}

recyclerView.addItemDecoration(StickyItemDecoration())

allprojects {
    repositories {
        ...
        maven { url 'https://jitpack.io' }
    }
}

implementation 'cn.numeron:recyclerview.decoration:latest_version'