Async加載圖片listview

package com.bwie.loadimage;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
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.bwie.loadimage.bean.MenuInfo;
import com.bwie.loadimage.utils.StreamTools;
import com.google.gson.Gson;

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

public class MainActivity extends AppCompatActivity {

    private ListView listview;

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

        getMenuInfo("http://apis.juhe.cn/cook/query.php?key=85ccc6561e8247986f378b20ef34589a&menu=" + URLEncoder.encode("祕製紅燒肉"));

    }

    public void getMenuInfo(String path) {


        new AsyncTask<String, Void, String>() {

            @Override
            protected String doInBackground(String... strings) {

                try {
                    HttpURLConnection connection = (HttpURLConnection) new URL(strings[0]).openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(5 * 1000);
                    connection.setReadTimeout(5 * 1000);

                    if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                        InputStream is = connection.getInputStream();
                        String json = StreamTools.getString(is);

                        return json;


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

            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);

                if (s != null) {
                    Gson gson = new Gson();
                    MenuInfo menuInfo = gson.fromJson(s, MenuInfo.class);
                    List<MenuInfo.ResultBean.DataBean.StepsBean> steps = menuInfo.getResult().getData().get(0).getSteps();
                    listview.setAdapter(new Myadapter(steps));
                }

            }
        }.execute(path);
    }

    public void loadImage(String imagePath, final ImageView imageview) {

        new AsyncTask<String, Void, Bitmap>() {

            @Override
            protected Bitmap doInBackground(String... strings) {
                try {
                    HttpURLConnection connection = (HttpURLConnection) new URL(strings[0]).openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(5 * 1000);
                    connection.setReadTimeout(5 * 1000);

                    if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                        InputStream is = connection.getInputStream();
                        Bitmap bitmap = BitmapFactory.decodeStream(is);
                        return bitmap;


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


            @Override
            protected void onPostExecute(Bitmap bitmap) {
                super.onPostExecute(bitmap);
                if (bitmap != null) {
                    imageview.setImageBitmap(bitmap);
                } else {
                    imageview.setImageResource(R.mipmap.ic_launcher);
                }
            }
        }.execute(imagePath);
    }

    class Myadapter extends BaseAdapter {

        public List<MenuInfo.ResultBean.DataBean.StepsBean> steps;

        public Myadapter(List<MenuInfo.ResultBean.DataBean.StepsBean> steps) {
            this.steps = steps;
        }

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

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

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

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            if (view == null) {
                view = View.inflate(getApplicationContext(), R.layout.item, null);

            }
            ImageView image = (ImageView) view.findViewById(R.id.image);
            TextView tv = (TextView) view.findViewById(R.id.tv);
            loadImage(steps.get(i).getImg(), image);

            tv.setText(steps.get(i).getStep());

            return view;
        }
    }
}