回收站视图：未连接适配器；跳过布局（API 回收站视图中的错误）

Question

这是回收者视图活动。在这里，我已经初始化了回收站视图。尽管我得到了错误。我可能哪里出错了。在日志猫中我得到了错误

No adapter attached; skipping layout.

在这里，我正在使用 API 在回收站视图中显示响应。我也在使用改造。在get data() 函数中，我正在获取响应状态并获取数据。

public class MainActivity extends AppCompatActivity {



    RecyclerView recyclerView;
    ListAdapter1 listAdapter;
//    List<SupermarketModels> supermarketModelsList = new ArrayList<>();
    ApiInterface apiInterface;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initialization();
        getdata();
    }

    private void initialization(){
        recyclerView = findViewById(R.id.recyclerview);
        Retrofit retrofit = APIClient.getclient();
        apiInterface = retrofit.create(ApiInterface.class);
    }

    private void setadapter(List<SupermarketModels> supermarketModels){

        listAdapter = new ListAdapter1(this, supermarketModels);

        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);

        recyclerView.setLayoutManager(linearLayoutManager);

        recyclerView.setAdapter(listAdapter);

        listAdapter.notifyDataSetChanged();


    }
    private void getdata(){
        apiInterface.getList().enqueue(new Callback<GetListResponse>() {
            @Override
            public void onResponse(Call<GetListResponse> call, Response<GetListResponse> response) {

                try {
                    if (response!= null){
                        if (response.body().getStatus().equals("1")){
                            setadapter(response.body().getData());


                        }
                        else {
                            Toast.makeText(MainActivity.this, response.body().getMessage(), Toast.LENGTH_SHORT).show();
                        }
                    }
                } catch (Exception e){
                    Log.e("exp", e.getLocalizedMessage());

                }

            }

            @Override
            public void onFailure(Call<GetListResponse> call, Throwable t) {

            }
        });

    }
} 

Answer 1

你必须 setOrientation() 到你的布局管理器。然后从那里删除 notifyDataSetChanged() 行。

LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
    linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL); //or HORIZONTLE,whatever you want
    
            recyclerView.setLayoutManager(linearLayoutManager);
    
            recyclerView.setAdapter(listAdapter);
    
            listAdapter.notifyDataSetChanged(); //remove this line from here

Answer 2

这个错误可以避免在实际加载数据时，在设置实际适配器之前先设置空适配器。在您调用 getdata() 之前的示例中，您只需像这样调用空适配器

EmptyAdapter emptyAdapter = new EmptyAdapter();
recyclerView.setAdapter(emptyAdapter);

这是你需要创建的空适配器类

import android.view.View;
import android.view.ViewGroup;

import androidx.recyclerview.widget.RecyclerView;

public class EmptyAdapter extends RecyclerView.Adapter<EmptyAdapter.EmptyHolder> {
@Override
public EmptyHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    return null;
}

@Override
public void onBindViewHolder(EmptyHolder holder, int position) {

}

@Override
public int getItemCount() {
    return 0;
}

class EmptyHolder extends RecyclerView.ViewHolder {
    public EmptyHolder(View itemView) {
        super(itemView);
    }
}
}

Answer 3

首先，让我们创建一个简单的适配器，它不接受任何数据，并且有一个允许我们添加数据和通知适配器的方法。

package adapters;

// TODO: Replace with your package

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

// TODO: Replace import of your package
import tech.gjirafa.tonosdemo.R;

public class SimpleAdapter extends RecyclerView.Adapter<SimpleAdapter.ViewHolder> {

private Context context;
// TODO: Replace data type from String with your model
private ArrayList<String> data = new ArrayList<>();

public SimpleAdapter(Context context) {
    this.context = context;
}

// TODO: Replace data type from String with your model
public void setData(ArrayList<String> data) {
    this.data.addAll(data);
    notifyDataSetChanged();
}

@NonNull
@Override
public SimpleAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    // TODO: adapter_news_item with your layout
    return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.adapter_news_item, parent, false));
}

@Override
public void onBindViewHolder(@NonNull SimpleAdapter.ViewHolder holder, int position) {
    // TODO: Add your bindings
}

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

static class ViewHolder extends RecyclerView.ViewHolder {

    // TODO: Declare your views here so you can access them onBindViewHolder()
    
    public ViewHolder(@NonNull View itemView) {
        super(itemView);
    }
}
}

然后在您的活动中，执行以下操作：

package activities;

// TODO: Replace with your package

import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

// TODO; Replace with your packageId

import com.google.gson.JsonObject;

import adapters.SimpleAdapter;
import tech.gjirafa.tonosdemo.R;

public class MainActivity extends AppCompatActivity {

SimpleAdapter simpleAdapter = new SimpleAdapter(this);

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // TODO: Replace your layout
    setContentView(R.layout.activity_demo);
    setupAdapter();
    fetchData();
}

private void setupAdapter() {
    RecyclerView recyclerView = findViewById(R.id.recyclerview);
    recyclerView.setAdapter(simpleAdapter);
    recyclerView.setLayoutManager(new LinearLayoutManager(this, RecyclerView.VERTICAL, false));
}

private void fetchData() {
    APIClient.getclient().create(ApiInterface.class).getList().enqueue(new Callback<GetListResponse>() {
        @Override
        public void onResponse(Call<GetListResponse> call, Response<GetListResponse> response) {
            try {
                if (response!= null){
                    if (response.body().getStatus().equals("1")){
                        simpleAdapter.setData(response.body().getData());
                    } else {
                        Toast.makeText(MainActivity.this, response.body().getMessage(), Toast.LENGTH_SHORT).show();
                    }
                }
            } catch (Exception e){
                Log.e("exp", e.getLocalizedMessage());
            }
        }

        @Override
        public void onFailure(Call<GetListResponse> call, Throwable t) {
            Log.e("onFailure", t.getLocalizedMessage());
        }
    });
}
}