NoClassDefFounderRor：解析失败：lorg/apache/http/protocolversion

Question

这段代码在leapdroid中工作得很好，但我得到了错误模拟器：

我的代码是：

package com.webstates.databaselesson2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONArray;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity
{

    String url="https://restcountries.eu/rest/v2/all";
    ArrayList<Item_Data> arrayList;
    ListView listView;
    Button bt1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ReadObjects();
        bt1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Read_From_Url();
            }
        });
        //



    }

    private void Read_From_Url() {


        RequestQueue requestQueue = Volley.newRequestQueue(this);
        JsonArrayRequest jsonArrayRequest=new JsonArrayRequest(Request.Method.GET, url, (String) null, new Response.Listener<JSONArray>() {
            @Override
            public void onResponse(JSONArray response) {
                Toast.makeText(getApplicationContext(),"done",Toast.LENGTH_LONG).show();
            }
        },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(getApplicationContext(),"error "+error.getMessage() ,Toast.LENGTH_LONG).show();
                    }
                }
        );
        requestQueue.add(jsonArrayRequest);



/*
        JsonArrayRequest jsonArrayRequest=new JsonArrayRequest(Request.Method.GET, url, (String) null, new Response.Listener<JSONArray>() {
            @Override
            public void onResponse(JSONArray response) {
                Toast.makeText(getApplicationContext(),"done",Toast.LENGTH_LONG).show();
            }
        },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(getApplicationContext(),"error "+error.getMessage() ,Toast.LENGTH_LONG).show();
                    }
                }
        );

        Mysingletone.getSingle(getApplicationContext()).add_to_Req(jsonArrayRequest);
*/
    }

    private void ReadObjects() {
        listView=findViewById(R.id.activity_main_listview);
        bt1=findViewById(R.id.activity_main_bt1);
        arrayList=new ArrayList<Item_Data>();

    }
}

Answer 1

较新版本的Android不支持Apache HTTP客户端。要解决此问题，请在清单文件中，在 标记中插入以下内容：

    <uses-library
        android:name="org.apache.http.legacy"
        android:required="false" />

关于谷歌为什么做出这一改变的更多信息可以在这里获得。