gson解析+listview展示

//逻辑代码块

package com.example.renzhili20181101;


import android.content.DialogInterface;

import android.content.Intent;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

import com.google.gson.Gson;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;

import java.net.URL;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private ListView listView;
    private Button button;
    private  final int UPDATE_UI=1;
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what){
                case UPDATE_UI:
                    List<List<String>> result = ( List<List<String>>) msg.obj;
                    myBase.getdatas(result);
                    break;
            }        }
    };
    private MyBase myBase;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取资源id
        listView = findViewById(R.id.listview);
        button = findViewById(R.id.but);
        //创建适配器
            myBase=new MyBase(MainActivity.this);
            listView.setAdapter(myBase);

        //点击获取数据
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //判断是否有网络     Urldata类中调用geturl方法判断
                if(!Urldata.geturl(MainActivity.this)){
                   // Toast.makeText(MainActivity.this,"无网络",Toast.LENGTH_LONG).show();
                    getAlertDialog();
                }
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                    //调用读取数据的方法
                        getdataurl();
                    }
                }).start();

            }
        });
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                String data = myBase.getItem(position);
                Toast.makeText(MainActivity.this,data,Toast.LENGTH_LONG).show();
            }
        });
    }
//AlertDialog弹框提示无网络的方法
    private void getAlertDialog() {
        new AlertDialog.Builder(MainActivity.this)
                .setTitle("无网络连接")
                .setMessage("无网络连接，确认去设置吗？")
                .setPositiveButton("确认", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                        //跳转设置网络连接
                        Intent wifiSettingsIntent = new Intent("android.settings.WIRELESS_SETTINGS");
                        startActivity(wifiSettingsIntent);
                       // Toast.makeText(MainActivity.this,"去设置",Toast.LENGTH_LONG).show();
                    }
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                })
                .show();
    }

    //  获取数据的方法
    private void getdataurl() {
        String path = "https://suggest.taobao.com/sug?code=utf-8&q=%E6%89%8B%E6%9C%BA";
        try {
            URL url = new URL(path);
            //打开链接
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("GET");
            urlConnection.setConnectTimeout(5000);
            urlConnection.setReadTimeout(5000);
            int responseCode = urlConnection.getResponseCode();
            if (responseCode == 200) {
                String getstream = getstream(urlConnection.getInputStream());
                //创建gson
                Gson gson = new Gson();
                UserBean userBean = gson.fromJson(getstream, UserBean.class);

                handler.sendMessage(handler.obtainMessage(UPDATE_UI,userBean.getResult()));

            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
//转换字节流
    private String getstream(InputStream inputStream) throws IOException {
        StringBuilder builder= new StringBuilder();
        BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
        for (String tmp = br.readLine();tmp!=null;tmp=br.readLine()){
            builder.append(tmp);
        }
        return builder.toString();
    }
}

//listview适配器BaseAdapter

package com.example.renzhili20181101;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import android.widget.VideoView;

import java.util.ArrayList;
import java.util.List;

public class MyBase extends BaseAdapter {
    private  List<List<String>>  result;
    private Context context;

    public MyBase(Context context) {
        this.context = context;
        result=new ArrayList<>();
    }

    public void getdatas( List<List<String>> result ) {
        this.result=result;
        notifyDataSetChanged();
    }
    @Override
    public int getCount() {
        return result.size();
    }

    @Override
    public String getItem(int position) {
        return result.get(position).get(0);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView==null){
            convertView=LayoutInflater.from(context).inflate(R.layout.item,parent,false);
            holder=new ViewHolder();
            holder.textView=convertView.findViewById(R.id.text_name);
            convertView.setTag(holder);
        }else{
            holder= (ViewHolder) convertView.getTag();
        }
        holder.textView.setText(getItem(position));
        return convertView;
    }
class ViewHolder{
        TextView textView;
}


}

//存放判断是否有网络的方法的类

package com.example.renzhili20181101;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

public class Urldata {
    //判断是否有网络的方法
    public  static  boolean geturl(Context context){
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
        return activeNetworkInfo!=null&&activeNetworkInfo.isAvailable();
    }

}

//配置文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.renzhili20181101">

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
                <!--打开数据网络设置的权限-->
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
            </intent-filter>
        </activity>


    </application>

</manifest>

//json解析bean类

package com.example.renzhili20181101;

import java.util.List;

public  class UserBean {
    public List<List<String>> result;

    public List<List<String>> getResult() {
        return result;
    }

    public void setResult(List<List<String>> result) {
        this.result = result;
    }
}