读取自己服务器上的数据写入listview的代码

这是一段我自己写的 读取自己服务器上的数据写入listview的代码

package com.jinesc.xbook;
import android.os.Handler;
import android.os.Message;
import androidx.appcompat.app.AppCompatActivity;  //原 import android.support.v7.app.AppCompatActivity; 替换
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;

import android.widget.Toast;

import org.json.JSONArray;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;


public class xBookType extends AppCompatActivity implements View.OnClickListener {
    public static final int SHOW_RESPONSE=0;//用于更新操作
    private Button sendRequest;
    private String str;
    private ArrayList<String> list = new ArrayList<String>();
    //private TextView responseText;


    //用于处理和发送消息的Hander
    //用于处理和发送消息的Hander
    private Handler handler=new Handler(){
        public void handleMessage(Message msg){
            //如果返现msg.what=SHOW_RESPONSE，则进行制定操作，如想进行其他操作，则在子线程里将SHOW_RESPONSE改变
            switch (msg.what){
                case SHOW_RESPONSE:
                    String response=(String)msg.obj;
                    //进行UI操作，将结果显示到界面上
                    //responseText.setText(pJsonStr(response));
                    //将字符读如全局变量中
                    str=pJsonStr(response);
                    //将内容加到list view中 使用了list
                    ListView listView = (ListView) findViewById(R.id.listview);//在视图中找到ListView
                    ArrayAdapter<String> adapter = new ArrayAdapter<String>(xBookType.this,android.R.layout.simple_list_item_1,list);//新建并配置ArrayAapeter
                    listView.setAdapter(adapter);

            }
        }
    };


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



        sendRequest=(Button)findViewById(R.id.send_request);
        sendRequest.setOnClickListener(this);

        sendRequestWithHttpURLConnection();  //读取了数据

        final ListView listView = (ListView) findViewById(R.id.listview);//在视图中找到ListView
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            //启动监听 list view
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {
                //监听单击事件
                String title=list.get(position).toString(); //获取点击的item的字符
                Toast.makeText(xBookType.this, "点击>>"+title+"---"+id, Toast.LENGTH_SHORT).show();
            }
        });

    }
    @Override

    public void onClick(View v) {//触发按钮
        if(v.getId()==R.id.send_request){
        sendRequestWithHttpURLConnection();

    }
    }
    private void sendRequestWithHttpURLConnection(){
        //开启线程来发起网络请求
        new Thread(new Runnable() {
            @Override
            public void run() {
                HttpURLConnection connection=null;
                try{

                    URL url=new URL(" 已经隐藏了 ");
                    connection=(HttpURLConnection)url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(8000);
                    connection.setReadTimeout(8000);

                    InputStream in=connection.getInputStream();
                    //下面对获取到的输入流进行读取
                    BufferedReader bufr=new BufferedReader(new InputStreamReader(in));
                    StringBuilder response=new StringBuilder();
                    String line=null;
                    while((line=bufr.readLine())!=null){
                        response.append(line);
                    }

                    Message message=new Message();
                    message.what=SHOW_RESPONSE;
                    //将服务器返回的数据存放到Message中
                    message.obj=response.toString();
                    handler.sendMessage(message);
                }catch(Exception e){
                    e.printStackTrace();
                }finally {
                    if(connection!=null){
                        connection.disconnect();
                    }
                }
            }
        }).start();
    }
    private String  pJsonStr(String jsonStr) {
        String result =  "";
         try{
            // 解析JSON字符
            JSONArray jsonArray = new JSONArray(jsonStr);
            list.clear(); //清除list的值
            for (int i = 0; i < jsonArray.length(); i++) {
                // JSON数组里面的具体-JSON对象
                JSONObject jsonObject = jsonArray.getJSONObject(i);
                String lx = jsonObject.optString("lx", null);
                //int sl = jsonObject.optInt("sl", 0); //整形
                String sl = jsonObject.optString("sl", null);
                result=String.format("%s%s.[%s]\n",result,lx,sl);
                //data[i]=String.format("%s",lx);
                list.add(lx);//加入list 为了能显示listview
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }

}

XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity"
    android:background="@mipmap/bg"
    android:gravity="center_horizontal"
    >

    <Button
        android:id="@+id/send_request"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="刷新图书类型" />

    <ListView
        android:id="@+id/listview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />






</LinearLayout>

返回的JSON字符

[{"lx":"Ebook","sl":"110"},    
{"lx":"三国","sl":"528"},    
{"lx":"仙侠","sl":"712"},    
{"lx":"全集","sl":"23409"},    
{"lx":"历史","sl":"92"},    
{"lx":"古龙全集","sl":"46"},  
{"lx":"末日","sl":"102"},    
 {"lx":"网络小说合集","sl":"2162"},    
{"lx":"翠微居全本","sl":"320"},    
{"lx":"血红","sl":"11"},    
{"lx":"西游","sl":"72"},    
{"lx":"超能","sl":"29"},    
{"lx":"都市","sl":"1307"},    
{"lx":"重生","sl":"1262"}]