null不能用stateFlow强制转换为非null类型RecyclerView

我从一个api中获得了一些类别，并试图在回收器视图上查看它们，但它不起作用：Main Activity：`@AndroidEntryPointclass MainActivity:AppCompatActivity（）｛private val TAG=“MEALZ”private lateinit var binding:ActivityMainBindingprivate val viewModel:MeaslViewModel by viewModels（）override fun onCreate（savedInstanceState:Bundle？）｛super.onCreate（savedInstance State）binding=ActivityMainBinding.fluge（layoutInflationer）setContentView（binding.root）

    val adapter = CategoryAdapter(this)
    binding.categoriesRv.adapter = adapter

    viewModel.getMeals()

    lifecycleScope.launch {
        viewModel.categories.collect {
            adapter.setData(it?.categories as List<Category>)
            Log.d(TAG, "onCreate: ${it?.categories}")
        }
    }
}

}`类别适配器：

`class CategoryAdapter（private val context:context？）：RecyclerView.Adapter<；类别适配器类别视图持有者>；（）｛private var categoryList:MutableList<；Category？>；=mutableListOf<；类别？>；（）

inner class CategoryViewHolder(itemView: CategoryLayoutBinding) :
    RecyclerView.ViewHolder(itemView.root) {
    val name = itemView.categoryNameTv
    val img = itemView.categoryIv
    val des = itemView.categoryDesTv


}

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CategoryViewHolder {
    val binding = CategoryLayoutBinding.inflate(LayoutInflater.from(context), parent, false)
    return CategoryViewHolder(binding)
}

override fun onBindViewHolder(holder: CategoryViewHolder, position: Int) {
    var category = categoryList[position]
    holder.name.text = category?.strCategory
    holder.des.text = category?.strCategoryDescription
    Glide.with(context as Context).load(category?.strCategoryThumb).into(holder.img)
}

override fun getItemCount(): Int {
    return categoryList.size
}

fun setData(CategoryList: List<Category>) {
    this.categoryList.addAll(CategoryList)
    notifyDataSetChanged() //to notify adapter that new data change has been happened to adapt it
}

}`