快哭了，救救孩子

听了你们的意见我开了两次AsynTask，我没有选择把图片存入SD卡，我是想直接在第二个AsynTask实现图片的设置，然后我这里就变成最后一个viewHolder轮播图片了，前面五个不显示.....

package com.example.group_buying;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.view.LayoutInflater;
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 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 menuAdapter extends BaseAdapter {
    List<LessonResult.LessonInfo> mLessonInfos;
    private Context mContext;
    Bitmap bitmapc=null;
    ViewHolder  viewHolder;
    public menuAdapter(Context context,List<LessonResult.LessonInfo> infos) {
        mLessonInfos=infos;
        mContext=context;
    }

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

    @Override
    public Object getItem(int position) {
        return mLessonInfos.get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
       viewHolder=new ViewHolder();
        if(convertView==null){
            LayoutInflater layoutInflater= (LayoutInflater) mContext.getSystemService(mContext.LAYOUT_INFLATER_SERVICE);
            convertView=layoutInflater.inflate(R.layout.menu_listview,null);
            viewHolder.food_View=convertView.findViewById(R.id.food);
            viewHolder.food_Name=convertView.findViewById(R.id.food_name);
            viewHolder.context=convertView.findViewById(R.id.context);
            viewHolder.food_price=convertView.findViewById(R.id.price);
            viewHolder.food_discount=convertView.findViewById(R.id.discount);
            viewHolder.sale=convertView.findViewById(R.id.sale);

            convertView.setTag(viewHolder);
        }else{
            viewHolder= (ViewHolder) convertView.getTag();
        }
        String url=mLessonInfos.get(position).getPictureurl();
        new RequestDataAsyncTaskSecond().execute(url);
        viewHolder.food_Name.setText(mLessonInfos.get(position).getFoodname());
        viewHolder.context.setText(mLessonInfos.get(position).getDescription());
        viewHolder.food_price.setText(mLessonInfos.get(position).getPrice());
        viewHolder.food_discount.setText(mLessonInfos.get(position).getAction());
        viewHolder.sale.setText(mLessonInfos.get(position).getCount());
        return convertView;
    }
    public class ViewHolder{
        public ImageView food_View;
        public TextView food_Name;
        public TextView context;
        public TextView food_price;
        public TextView food_discount;
        public TextView sale;
    }
    public class RequestDataAsyncTaskSecond extends AsyncTask<String,Void,Bitmap> {
    String str=null;
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            //
        }

        protected Bitmap doInBackground(String...  path) {
            str=path[0];
            try {
                URL url = new URL(str);
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setConnectTimeout(5000);
                conn.setRequestMethod("GET");
                if (conn.getResponseCode() == 200) {
                    InputStream inputStream = conn.getInputStream();
                    Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                    return bitmap;
                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return null;
        }
        protected void onPostExecute(Bitmap bitmap) {
            viewHolder.food_View.setImageBitmap(bitmap);

        }

    }

}