如何使用FireCloud更新我的Recyclerview？我有一个错误，我不能再次初始化绑定

Question

我的适配器类是：

类categoryAdapter（private val categoryList：list）：recyClerview.Adapter＆lt; categoryAdapter.customViewholder＆gt;（）{} {

inner class CustomViewHolder(view: View) : RecyclerView.ViewHolder(view)

override fun onCreateViewHolder(
    parent: ViewGroup,
    viewType: Int
): CategoryAdapter.CustomViewHolder {
    val view = LayoutInflater.from(parent.context)
        .inflate(R.layout.category_item_layout, parent, false)
    parent.context
    return CustomViewHolder(view)
}

override fun onBindViewHolder(holder: CustomViewHolder, position: Int) {
    val category = categoryList[position]
    val view = holder.itemView
    holder.itemView.context

    val background = view.findViewById<ImageView>(R.id.categoryBackground)
    val img = view.findViewById<ImageView>(R.id.categoryImg)

    if (category.Background.isNotEmpty()) {
        var buttonDrawable = background.background
        buttonDrawable = DrawableCompat.wrap(buttonDrawable)
        DrawableCompat.setTint(buttonDrawable, Color.parseColor(category.Background.toString()))
        background.background = buttonDrawable
    } else {
        background.setImageDrawable(R.id.notification.toDrawable())
    }

    if (category.Img.isNotEmpty()) {
        Picasso.get().load(category.Img).into(img)
    }

    view.setOnClickListener {
        
        ProductsFragment().setCategoryType(category.Nombre)
        notifyDataSetChanged()
    }
}

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

}

，片段为：： class products fragment：fragment（）{

private lateinit var binding: FragmentProductsBinding
private var db = FirebaseFirestore.getInstance()

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View {
    binding = FragmentProductsBinding.inflate(layoutInflater)
    return binding.root
}

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)

    category()

    products()

}

fun setCategoryType(name:String) {
    db.collection("Productos").whereEqualTo("Categoria", name).get().addOnSuccessListener { documents ->
        val productList = mutableListOf<ProductsDataClass>()
        for (document in documents) {
            val productObject = document.toObject(ProductsDataClass::class.java)
            productList.add(productObject)
            binding.productsRecyclerView.adapter = ProductsAdapter(productList)
            binding.productsRecyclerView.layoutManager = GridLayoutManager(context, 3)
        }
    }.addOnFailureListener { exception ->
        Log.w("Error", "Error getting documents: ", exception)
        Toast.makeText(context, getString(R.string.error), Toast.LENGTH_SHORT).show()
    }

}

private fun products() {
    db.collection("Productos").get().addOnSuccessListener { documents ->
        val productList = mutableListOf<ProductsDataClass>()
        for (document in documents) {
            val productObject = document.toObject(ProductsDataClass::class.java)
            productList.add(productObject)
            binding.productsRecyclerView.adapter = ProductsAdapter(productList)
            binding.productsRecyclerView.layoutManager = GridLayoutManager(context, 3)
        }
    }.addOnFailureListener { exception ->
        Log.w("Error", "Error getting documents: ", exception)
        Toast.makeText(context, getString(R.string.error), Toast.LENGTH_SHORT).show()
    }
}

private fun category() {
    db.collection("Categoria").get().addOnSuccessListener { documents ->
        val categoryList = mutableListOf<CategoryDataClass>()
        for (document in documents) {
            val categoryObject = document.toObject(CategoryDataClass::class.java)
            categoryList.add(categoryObject)
            binding.categoryRecyclerView.adapter = CategoryAdapter(categoryList)
            binding.categoryRecyclerView.layoutManager = LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false)
        }
    }.addOnFailureListener { exception ->
        Log.w("Error", "Error getting documents: ", exception)
        Toast.makeText(context, getString(R.string.error), Toast.LENGTH_SHORT).show()
    }
}

}

我想要当您从类别中选择一个元素时，您会在类别上使用此名称的元素更新回收器视图，但是我的recycler视图没有更新

Answer 1

在这里，您正在调用setCategoryType（category.nombre）在productsfragment fragment的新实例中，而不是在您当前的片段实例中。您可以在适配器中发送当前片段的引用，也可以使用接口或回调，该接口或回调将在适配器内获取时更新数据。

例如，使用回调

class CategoryAdapter(
    private val categoryList: List<CategoryDataClass>,
    private val onCategorySelected: (CategoryDataClass) -> Unit
): RecyclerView.Adapter<CategoryAdapter.CustomViewHolder>(){
    ...// Skipping rest of the code

    override fun onBindViewHolder(holder: CustomViewHolder, position: Int) {
        val category = categoryList[position]
        val view = holder.itemView
        holder.itemView.context
        ...// Skipping rest of the code

        view.setOnClickListener {

            onCategorySelected(category)
        }
    }
}

和片段类，在您初始化此类别的情况下，将其更改为类似的东西：

binding.categoryRecyclerView.adapter = CategoryAdapter(categoryList) { category ->
    setCategoryType(category.Nombre)
}