Recyclerview在列表中的每个项目上添加相同的项目

Question

I have a problem with my recyclverview.I'm retriving a list from firebase and in this list getting recreated on every iteration that is makes. My goal is that the all seperate items in the list should be printed out.

Here is my Recyclerview adapter

override fun onCreateViewHolder(viewGroup: ViewGroup, i: Int): ItemsViewHolder {
    val view = LayoutInflater.from(viewGroup.context)
        .inflate(R.layout.card_view_fragment, viewGroup, false)
    addItems(itemsList)
    return ItemsViewHolder(view)
}

override fun onBindViewHolder(viewHolder: ItemsViewHolder, postion: Int) {
    viewHolder.bindView(itemsList[postion])
}

override fun getItemCount(): Int {
    return itemsList.count()
}

fun addItems(items: List<Items>) {
    itemsList.addAll(items)
}

i can provide more code if needed

Updated requested by Shermano

fun getEanItems(eanCode: ArrayList<String?>) {
    val service = RetrofitInstance().getRetrofitInstance().create(getItemApi::class.java)
    GlobalScope.launch(Dispatchers.Main) {
        repeat(eanCode.size) { count ->
            val call = service.getItemsData(eanCode[count].toString())
            delay(500)
            call.enqueue(object : Callback<ItemsList> {
                override fun onFailure(call: Call<ItemsList>, t: Throwable) {
                    Toast.makeText(context, "Could not fetch data", Toast.LENGTH_LONG).show()
                }
                override fun onResponse(call: Call<ItemsList>, response: Response<ItemsList>) {
                    Log.i(TAG, response.body().toString())
                    Toast.makeText(context, response.toString(), Toast.LENGTH_SHORT).show()
                    response.body()?.getitemsArrayList()?.let { generateItemsList(it) }  



fun generateItemsList(getitemsArrayList: ArrayList<Items>) {
    recyclerView?.apply {
        layoutManager = LinearLayoutManager(context, LinearLayoutManager.VERTICAL, false)
        setHasFixedSize(true)
        adapter = ItemsAdapter(getitemsArrayList)

    }
}

I might be blind, but i dont see where i fit in this addItems in this code, im kinda stuck with my mindset of adapter = ItemsAdapter(getitemsArrayList)

Answer 1

Problem is in the onCreateViewHolder method , where you have written addItems() method.

I would suggest you to refer documentation, here is the excerpt from the same:

VH onCreateViewHolder (ViewGroup parent, int viewType)

Called when RecyclerView needs a new RecyclerView.ViewHolder of the given type to represent an item.

This new ViewHolder should be constructed with a new View that can represent the items of the given type. You can either create a new View manually or inflate it from an XML layout file.

The new ViewHolder will be used to display items of the adapter using onBindViewHolder(ViewHolder, int, List). Since it will be re-used to display different items in the data set, it is a good idea to cache references to sub views of the View to avoid unnecessary findViewById(int) calls.

About adding items: I would say you should call addItems method from the place you want to add items into the list and there by in the RecyclerView.

And I would say you should also add below line in your addItems method inside you have written in the adapter class:

mAdapter.notifyItemRangeInserted(startPosition, itemcount);

Answer 2

调用时，您将传递itemlist addItems(itemsList)和内部方法定义..您正在将相同列表的项目添加到自身中。

Answer 3

It works now thank you all for the responses giving me the right direction :)

fun fetchDataFromFirebase() {
    val databaseReference = FirebaseDatabase.getInstance().getReference("EAN")
    listOfArray = arrayListOf()
    listOfItems = arrayListOf()

    databaseReference.addValueEventListener(object : ValueEventListener {
        override fun onCancelled(databaseError: DatabaseError) {}
        override fun onDataChange(dataSnapshot: DataSnapshot) {
            for (eanCodes in dataSnapshot.children) {
                if (dataSnapshot.exists()) {
                    Log.i(TAG + "EAN", eanCodes.toString())
                    val eanItems = eanCodes.getValue(FirebaseEanCode::class.java)
                    listOfArray.add(eanItems?.eanValue)
                }
            }
            getEanItems(listOfArray)
        }

    })
}


fun getEanItems(eanCode: ArrayList<String?>) {
    val service = RetrofitInstance().getRetrofitInstance().create(getItemApi::class.java)
    GlobalScope.launch(Dispatchers.Main) {
        repeat(eanCode.size) { count ->
            val call = service.getItemsData(eanCode[count].toString())
            delay(2500)
            call.enqueue(object : Callback<ItemsList> {
                override fun onFailure(call: Call<ItemsList>, t: Throwable) {
                   Toast.makeText(activity, "Could not fetch data", Toast.LENGTH_LONG).show()
                }

                override fun onResponse(call: Call<ItemsList>, response: Response<ItemsList>) {
                    Log.i(TAG, response.body().toString())
                    Toast.makeText(activity, response.toString(), Toast.LENGTH_SHORT).show()
                    response.body()?.getitemsArrayList()?.let { generateItemsList(it) }


                }
            })
        }
    }
}


fun generateItemsList(getitemsArrayList: ArrayList<Items>) {
    recyclerView?.apply {
        layoutManager = LinearLayoutManager(context, LinearLayoutManager.VERTICAL, false)
        setHasFixedSize(true)
        adapter = ItemsAdapter(addItems(getitemsArrayList))
        recyclerView.setHasFixedSize(true)

    }
}


fun addItems(items: ArrayList<Items>): ArrayList<Items> {
    listOfItems.addAll(items)
    recyclerView.setHasFixedSize(true)
    recyclerView.adapter?.notifyDataSetChanged()
    return listOfItems
}