Java 错误地覆盖包

Incorrectly overriding a package

提问by Kartik Sharma

I am getting this error.

我收到此错误。

03-22 11:41:20.439 20933-20933/com.androidcss.jsonexample E/RecyclerView: No adapter attached; skipping layout 03-22 11:41:20.760 20933-20933/com.androidcss.jsonexample W/art: Before Android 4.1, method int android.support.v7.widget.ListViewCompat.lookForSelectablePosition(int, boolean) would have incorrectly overridden the package-private method in android.widget.ListView

03-22 11:41:20.439 20933-20933/com.androidcss.jsonexample E/RecyclerView：没有附加适配器；跳过布局 03-22 11:41:20.760 20933-20933/com.androidcss.jsonexample W/art：在 Android 4.1 之前，方法 int android.support.v7.widget.ListViewCompat.lookForSelectablePosition(int, boolean) 会错误地覆盖android.widget.ListView 中的 package-private 方法

MainActivity.java

主活动.java

package com.androidcss.jsonexample;

import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    // CONNECTION_TIMEOUT and READ_TIMEOUT are in milliseconds
    public static final int CONNECTION_TIMEOUT = 10000;
    public static final int READ_TIMEOUT = 15000;
    private RecyclerView mRVFishPrice;
    private AdapterFish mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //Make call to AsyncTask
        new AsyncLogin().execute();


    }

    private class AsyncLogin extends AsyncTask<String, String, String> {
        ProgressDialog pdLoading = new ProgressDialog(MainActivity.this);
        HttpURLConnection conn;
        URL url = null;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

            //this method will be running on UI thread
            pdLoading.setMessage("\tLoading...");
            pdLoading.setCancelable(false);
            pdLoading.show();

        }

        @Override
        protected String doInBackground(String... params) {
            try {

                // Enter URL address where your json file resides
                // Even you can make call to php file which returns json data
                url = new URL("https://newsapi.org/v1/articles?source=the-next-web&sortBy=latest&apiKey=bdba5de1b490495796a1595f77ed3f37");

            } catch (MalformedURLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                return e.toString();
            }
            try {

                // Setup HttpURLConnection class to send and receive data from php and mysql
                conn = (HttpURLConnection) url.openConnection();
                conn.setReadTimeout(READ_TIMEOUT);
                conn.setConnectTimeout(CONNECTION_TIMEOUT);
                conn.setRequestMethod("GET");

                // setDoOutput to true as we recieve data from json file
                conn.setDoOutput(true);

            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
                return e1.toString();
            }

            try {

                int response_code = conn.getResponseCode();

                // Check if successful connection made
                if (response_code == HttpURLConnection.HTTP_OK) {

                    // Read data sent from server
                    InputStream input = conn.getInputStream();
                    BufferedReader reader = new BufferedReader(new InputStreamReader(input));
                    StringBuilder result = new StringBuilder();
                    String line;

                    while ((line = reader.readLine()) != null) {
                        result.append(line);
                    }

                    // Pass data to onPostExecute method
                    return (result.toString());

                } else {

                    return ("unsuccessful");
                }

            } catch (IOException e) {
                e.printStackTrace();
                return e.toString();
            } finally {
                conn.disconnect();
            }


        }

        @Override
        protected void onPostExecute(String result) {

            //this method will be running on UI thread

            pdLoading.dismiss();
            List<Item> data=new ArrayList<>();

            pdLoading.dismiss();
            try {

                JSONObject object= new JSONObject(result);
                JSONArray array = object.getJSONArray("articles");

                // Extract data from json and store into ArrayList as class objects
                for(int i=0;i<array.length();i++){
                    JSONObject json_data = array.getJSONObject(i);
                    Item item= new Item();
                    item.name= json_data.getString("title");

                    data.add(item);
                }

                // Setup and Handover data to recyclerview
                mRVFishPrice = (RecyclerView)findViewById(R.id.fishPriceList);
                mAdapter = new AdapterFish(MainActivity.this, data);
                mRVFishPrice.setAdapter(mAdapter);
                mRVFishPrice.setLayoutManager(new LinearLayoutManager(MainActivity.this));

            } catch (JSONException e) {
                Toast.makeText(MainActivity.this, e.toString(), Toast.LENGTH_LONG).show();
            }

        }

    }
}

AdapterFish.java

AdapterFish.java

package com.androidcss.jsonexample;

import android.content.Context;
import android.support.v4.content.ContextCompat;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.bumptech.glide.Glide;
import java.util.Collections;
import java.util.List;

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

    private Context context;
    private LayoutInflater inflater;
    List<Item> data= Collections.emptyList();
    Item current;
    int currentPos=0;

    // create constructor to innitilize context and data sent from MainActivity
    public AdapterFish(Context context, List<Item> data){
        this.context=context;
        inflater= LayoutInflater.from(context);
        this.data=data;
    }

    // Inflate the layout when viewholder created
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view=inflater.inflate(R.layout.card, parent,false);
        MyHolder holder=new MyHolder(view);
        return holder;
    }

    // Bind data
    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

        // Get current position of item in recyclerview to bind data and assign values from list
        MyHolder myHolder= (MyHolder) holder;
        Item current=data.get(position);

        myHolder.name.setText(current.getName());

        // load image into imageview using glide
        /*Glide.with(context).load("http://192.168.1.7/test/images/" + current.fishImage)
                .placeholder(R.drawable.ic_img_error)
                .error(R.drawable.ic_img_error)
                .into(myHolder.ivFish);*/

    }

    // return total item from List
    @Override
    public int getItemCount() {
        return data.size();
    }


    class MyHolder extends RecyclerView.ViewHolder{

        TextView name;


        // create constructor to get widget reference
        public MyHolder(View itemView) {
            super(itemView);
            name = (TextView)itemView.findViewById(R.id.name);


        }

    }

}

Item.java

项目.java

package com.androidcss.jsonexample;

public class Item {

    String name;

    public String getName() {
        return name;
    }
}

回答by Zarul Izham

You need to setLayoutManagerbefore setAdapter.

你需要setLayoutManager之前setAdapter。

回答by Mohammed Atif

You are initializing the RecyclerViewin AsynTask, that means your ReyclerViewis not ready when view is created.

您正在初始化RecyclerViewin AsynTask，这意味着您ReyclerView在创建视图时还没有准备好。

Make the following changes.

进行以下更改。

//make list as global variable
private List<Item> data;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //view should be initialized in UI thread
    data=new ArrayList<>();
    mRVFishPrice = (RecyclerView)findViewById(R.id.fishPriceList);
    mAdapter = new AdapterFish(MainActivity.this, data);
    mRVFishPrice.setLayoutManager(new LinearLayoutManager(MainActivity.this));
    mRVFishPrice.setAdapter(mAdapter);

    //Make call to AsyncTask
    new AsyncLogin().execute();
}

Then in your onPostExecute

然后在你的 onPostExecute

replace -

代替 -

mRVFishPrice = (RecyclerView)findViewById(R.id.fishPriceList);
mAdapter = new AdapterFish(MainActivity.this, data);
mRVFishPrice.setAdapter(mAdapter);
mRVFishPrice.setLayoutManager(new LinearLayoutManager(MainActivity.this));

with

和

mAdapter.notifyDatasetChanged();

and also, make sure you remove the List<Item> datafrom postexecute and make it global

而且，请确保List<Item> data从 postexecute 中删除并使其成为全局

And please use Volley to make API calls instead of implementing Custom Background Task. Volley Handles the API calls asynchronously without messing up your Actual Code.

并且请使用 Volley 进行 API 调用，而不是实现自定义后台任务。Volley 异步处理 API 调用，而不会弄乱您的实际代码。

回答by Jatin Shara

I faced the same issue. The problem was in Layout. You should first verify that if your Views and Layouts are in correct order.

我遇到了同样的问题。问题出在布局中。您应该首先验证您的视图和布局的顺序是否正确。