override fun onCreateView(...  ): View? 
   {
        val rootview = inflater.inflate(R.layout.fragment_menu, 
        container,false)

        val recycler_menu_list = 
         rootview.findViewById(R.id.recycler_menu_list) as RecyclerView

        recycler_menu_list.layoutManager = LinearLayoutManager(activity)

        val data =  ...

        foodCardAdapter = FoodCardAdapter()

        recycler_menu_list.adapter=foodCardAdapter

        foodCardAdapter.submitList(data)      

       //make sure that the return view is one declared above up and is 
       //not the default 'inflater.inflate(R.layout.fragment_menu,         
       //container,false)' created by the ide

        return rootview    
    }

//当你在创建阶段没有设置适配器时发生:当api response得到Its Working时调用notifyDataSetChanged()

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity);


        magazineAdapter = new MagazineAdapter(getContext(), null, this );
        newClipRecyclerView.setAdapter(magazineAdapter);
        magazineAdapter.notifyDataSetChanged();

       APICall();
}

public void APICall() {
    if(Response.isSuccessfull()){
    mRecyclerView.setAdapter(mAdapter);
   }
}
Just move setting the adapter into onCreate with an empty data and when you have the data call:

mAdapter.notifyDataSetChanged();

首先初始化适配器

public void initializeComments(){
    comments = new ArrayList<>();

    comments_myRecyclerView = (RecyclerView) findViewById(R.id.comments_recycler);
    comments_mLayoutManager = new LinearLayoutManager(myContext);
    comments_myRecyclerView.setLayoutManager(comments_mLayoutManager);

    updateComments();
    getCommentsData();

}

public void updateComments(){

    comments_mAdapter = new CommentsAdapter(comments, myContext);
    comments_myRecyclerView.setAdapter(comments_mAdapter);
}

当数据集中发生变化时，只需调用updateComments方法。

只需将以下内容添加到RecyclerView

app:layoutManager="android.support.v7.widget.LinearLayoutManager"

例子:

   <android.support.v7.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical"
        app:layoutManager="android.support.v7.widget.LinearLayoutManager"
        app:layout_constraintBottom_toTopOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

    </android.support.v7.widget.RecyclerView>

我遇到了同样的问题，并意识到我在从源检索数据后同时设置了LayoutManager和适配器，而不是在onCreate方法中设置这两个。

salesAdapter = new SalesAdapter(this,ordersList);
        salesView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
        salesView.setAdapter(salesAdapter);

然后将数据更改通知适配器

               //get the Orders
                Orders orders;
                JSONArray ordersArray = jObj.getJSONArray("orders");
                    for (int i = 0; i < ordersArray.length() ; i++) {
                        JSONObject orderItem = ordersArray.getJSONObject(i);
                        //populate the Order model

                        orders = new Orders(
                                orderItem.getString("order_id"),
                                orderItem.getString("customer"),
                                orderItem.getString("date_added"),
                                orderItem.getString("total"));
                        ordersList.add(i,orders);
                        salesAdapter.notifyDataSetChanged();
                    }

我得到了同样的问题，我做的每件事都是正确的，除了在xml文件:

step first 1: initialize recyclerview & List & Adaptor: RecyclerView recyclerview; List<ModelName> list; ProvideBidAdaptor adaptor; step 2: bind it in onCreate- recyclerview = findByViewId(R.id.providerBidRV); recyclerview.setLayoutManager(new LinearLayoutManager(this)); recyclerview.setHasFixedSize(true); list = new ArrayList<>(); step 3: Where you getting response or list - add list- (i am getting from response)> responseList.addAll(response.getResponse()); adaptor = new ProvideBidAdaptor(this, responseList); binding.detailsRV.setAdapter(adaptor);

这是我的xml文件，我实现RecyclerView: 我忘记了线性布局的方向，经过这个修正- RecyclerView附加。

<?xml version="1.0" encoding="utf-8"?>
    <layout>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        tools:context=".activities.Bidding.ProvideBid">

        <include
            android:id="@+id/toolbar"
            layout="@layout/app_toolbar"/>

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/providerBidRV"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>
    </LinearLayout>
</layout> 

这是适配器:

    public class ProvideBidAdaptor extends RecyclerView.Adapter<ProvideBidAdaptor.ViewHolder> {
    Context context;
    List<Response> responseList;
    DateTime dateTimeInstance = new DateTime();

    public ProvideBidAdaptor(Context context, List<Response> responseList) {
        this.context = context;
        this.responseList = responseList;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).inflate(R.layout.geo_presence_item_list, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        final Response detailsResponse = responseList.get(position);
        if (!detailsResponse.getUserId().isEmpty()) {

            holder.day.setText(detailsResponse.getDay());
            holder.locationType.setText(detailsResponse.getLocationType());

        }

    }

    @Override
    public int getItemCount() {
        return responseList.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        TextView date,locationType;
        CardView provideBidCV;
        LinearLayout dayLLayout,locationTypeLLayout;
        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            date = itemView.findViewById(R.id.date_value);
            day = itemView.findViewById(R.id.day_value);
            locationType = itemView.findViewById(R.id.locationType_value);

            locationTypeLLayout = itemView.findViewById(R.id.locationTypeLLayout);

        }
    }
}