请求网络数据

package com.example.lianxi01;

import android.graphics.Bitmap;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import com.google.gson.Gson;

import java.util.List;

public class MainActivity extends AppCompatActivity {

    private ListView listView;
    private String urlTotal="http://api.expoon.com/AppNews/getNewsList/type/1/p/1";
    private List<Product.DataBean> dataList;
    private TextView tv3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.lv);
        initdata();
    }

    public void initdata(){
        new MysyncTask().execute(urlTotal);
    }
    class MysyncTask extends AsyncTask<String,Void,String>{
        private List<Product.DataBean> data;

        @Override
        protected String doInBackground(String... strings) {
            String url=strings[0];
            String netjson = NetWordUtils.getNetjson(url);
            return netjson;
        }
        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            Gson gson=new Gson();
            Product product = gson.fromJson(s, Product.class);
            dataList = product.getData();
            MyAdapter myAdapter=new MyAdapter();
            listView.setAdapter(myAdapter);
        }
    }

    class MyAdapter extends BaseAdapter{

        @Override
        public int getCount() {
            return dataList.size();
        }

        @Override
        public Object getItem(int i) {
            return dataList.get(i);
        }

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

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            view = View.inflate(MainActivity.this, R.layout.item, null);
            TextView tv1 = (TextView)view.findViewById(R.id.tv1);
            TextView tv2 = (TextView)view.findViewById(R.id.tv2);
            TextView tv3 = (TextView)view.findViewById(R.id.tv3);
            ImageView iv = (ImageView)view.findViewById(R.id.iv);
            tv1.setText(dataList.get(i).getNews_id());
            tv2.setText(dataList.get(i).getNews_title());
            tv3.setText(dataList.get(i).getNews_summary());
            new MyImagerSyncTask(iv).execute(dataList.get(i).getPic_url());

            return view;
        }
    }
    class MyImagerSyncTask extends AsyncTask<String,Void,Bitmap>{
        private ImageView iv;

        public MyImagerSyncTask(ImageView iv) {
            this.iv=iv;
        }

        @Override
        protected Bitmap doInBackground(String... strings) {
            String urlstring = strings[0];
            Bitmap netimage = NetWordUtils.getNetimage(urlstring);
            return netimage;
        }

        @Override
        protected void onPostExecute(Bitmap bitmap) {
            super.onPostExecute(bitmap);
            iv.setImageBitmap(bitmap);
        }
    }
}