4.0版本 MutiItemAdapter中添加Holder的方式是否可以更简练些，下面是我的一些尝试

其实在MultiItemAdapter添加各种addItemType会导致代码冗余的很，适当的抽离和使用反射会使代码简介很多很多，比如我在项目中的尝试：

class DetailsAdapter : BaseMultiItemAdapter<Floors>() {
    init {
        // 根据type添加返回type 滑动时会根据对应额Position去创建对应的Holder
        onItemViewType { position, list ->
            list[position].itemType
        }

        
        addDetailsVH(T_BRAND_HEADER.hashCode(), GDBrandHeaderVH::class.java, R.layout.item_vh_details_brand_header)
        addDetailsVH(T_TOP_BANNER.hashCode(), GDTopBannerVH::class.java, R.layout.item_vh_details_top_banner) 
        addDetailsVH(T_PRESALE_PRICE.hashCode(), GDPresalePricesVH::class.java,R.layout.item_vh_details_presale_prices)
        addDetailsVH(T_ACTIVITY_PRICE.hashCode(), GDActivityPricesVH::class.java, R.layout.item_vh_activity_prices)
       ......
    }


   /**
     * 通过传递的过来的Class类型，创建出对应的ViewHolder
     */
    private fun <E : DetailsEntity, T : BaseGDVH<E>> addDetailsVH(
        itemType: Int, // holder类型
        vh: Class<T>,  // holder类名
        @LayoutRes layoutId: Int // holder布局
    ) {
        addItemType(itemType, object : OnMultiItemAdapterListener<DetailsEntity?, T> {
            override fun onCreate(context: Context, parent: ViewGroup, viewType: Int): T {
                // 获取到默认的构造方法
                val constructors = vh.declaredConstructors[0]
                // 获取到绑定的view
                val view = LayoutInflater.from(context).inflate(layoutId, parent, false)
                return constructors.newInstance(view) as T
            }

            override fun onBind(holder: T, position: Int, item: DetailsEntity?) {
                if (item == null) {
                    holder.onHiddenVh()
                    return
                }

                holder.onBindData(item as E)
            }

            // 商详的holder都是跨满屏幕
            override fun isFullSpanItem(itemType: Int): Boolean {
                return true
            }
        })
    }
}

/**
* 抽离出来的一个基类，限定绑定类型，方便以后扩展
*/
abstract class BaseGDVH<T : DetailsEntity>(view: View) : RecyclerView.ViewHolder(view) {
    abstract fun onBindData(data: T)

    // 当类型解析失败（不匹配），或者是数据为空时，需要将当前的Holder直接隐藏掉
    fun onHiddenVh() {
        itemView.layoutParams.apply {
            width = 0
            height = 0
        }
        itemView.visibility = View.GONE
    }
}

Start by reviewing MultiItemAdapter's addItemType API and the DetailsAdapter example, including addDetailsVH and BaseGDVH. Define the desired registration approach while preserving holder creation, binding, null handling, and full-span behavior; the issue is done when the maintainers agree on and document the resulting API.