麻烦老师看下为什么没法显示ListView

Activity中：

package com.example.felix.homeworkapp;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.widget.ListView;
import android.widget.Toast;

import com.example.felix.homeworkapp.Adapter.GridAdapter1;
import com.example.felix.homeworkapp.Adapter.MenuAdapter1;
import com.example.felix.homeworkapp.Info.MenuInfo;
import com.example.felix.homeworkapp.Info.MenuResult;

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

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

public class MenuActivity extends AppCompatActivity {

    private ListView menuListView;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fragment_main);
        menuListView = findViewById(R.id.mainFragment_listView);
        //LayoutInflater layoutInflater= (LayoutInflater) getSystemService(getApplicationContext().LAYOUT_INFLATER_SERVICE);
    }

    public class MenuAsyncTask extends AsyncTask<Void,Integer, String>{

        @Override
        protected void onPreExecute() {
            Toast.makeText(MenuActivity.this,"开始准备获取数据",Toast.LENGTH_LONG).show();
            super.onPreExecute();
        }

        @Override
        protected String doInBackground(Void... voids) {
            return request("http://www.imooc.com/api/shopping?type=11");
        }

        private String request(String s) {
            try {
                URL url=new URL(s);
                HttpURLConnection connection= (HttpURLConnection) url.openConnection();
                connection.setConnectTimeout(30*1000);
                connection.setRequestMethod("GET");
                connection.connect();
                int reponseCode=connection.getResponseCode();
                String reponseMessage=connection.getResponseMessage();

                if(reponseCode==HttpURLConnection.HTTP_OK){
                    InputStream inputStream=connection.getInputStream();
                    Bitmap bitmap= BitmapFactory.decodeStream(inputStream);
                }else{
                    Toast.makeText(MenuActivity.this,"ERROR",Toast.LENGTH_LONG).show();
                }
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onProgressUpdate(Integer... values) {
            super.onProgressUpdate(values);
        }

        @Override
        protected void onPostExecute(String s) {
            MenuResult menuResult=new MenuResult();
            try {
                JSONObject jsonObject=new JSONObject();
                JSONArray dataArray=jsonObject.getJSONArray("data");
                int status=jsonObject.getInt("status");
                menuResult.setmStatus(status);

                List<MenuInfo> menuInfoList=new ArrayList<>();
                for(int i=0;i<dataArray.length();i++){
                    MenuInfo menuInfo=new MenuInfo();
                    JSONObject js= (JSONObject) dataArray.get(i);
                    menuInfo.setId(js.getInt("id"));
                    menuInfo.setName(js.getInt("name"));
                    menuInfo.setImg(js.getString("img"));
                    menuInfo.setAction(js.getInt("action"));
                    menuInfo.setCount(js.getInt("count"));
                    menuInfo.setPrice(js.getInt("price"));
                    menuInfoList.add(menuInfo);
                }
                menuResult.setmDataInfoList(menuInfoList);
            } catch (JSONException e) {
                e.printStackTrace();
            }
            MenuAdapter1 menuAdapter1=new MenuAdapter1(menuResult.getmDataInfoList(),MenuActivity.this);
            menuListView.setAdapter(menuAdapter1);
            super.onPostExecute(s);
        }
    }

}

Adapter中：

package com.example.felix.homeworkapp.Adapter;

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

import com.example.felix.homeworkapp.Info.MenuInfo;
import com.example.felix.homeworkapp.R;

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

public class MenuAdapter1 extends BaseAdapter {
    List<MenuInfo> menuInfoList=new ArrayList<>();
    private Context context;

    public MenuAdapter1(List<MenuInfo> menuInfoList, Context context) {
        this.menuInfoList = menuInfoList;
        this.context = context;
    }

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

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

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

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        ViewHolder viewHolder=new ViewHolder();
        if(view==null){
            view=View.inflate(context, R.layout.item_fragment_main,null);
            viewHolder.img_dish=view.findViewById(R.id.item_fragment_main_imageView);
            viewHolder.tv_dish_name=view.findViewById(R.id.item_fragment_main_textView);
            view.setTag(viewHolder);
        }else {
            view= (View) view.getTag();
        }
        MenuInfo menuInfo=menuInfoList.get(i);
        //viewHolder.img_dish.setImageBitmap(menuInfo.getImg());
        viewHolder.tv_dish_name.setText(menuInfo.getName());
        return view;
    }
    public class ViewHolder {
        ImageView img_dish;
        TextView tv_dish_name;
        //TextView tv_dish_name;
    }
}

以及顺便请老师看下

viewHolder.img_dish.setImageBitmap(menuInfo.getImg());

get方法中是String这里应该怎么进行格式转换，谢谢老师