获取网络字符串及图片

package activity.example.com.day;


import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Message;
import android.provider.ContactsContract;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.view.menu.BaseMenuPresenter;
import android.util.Log;
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 android.widget.Toast;


import com.google.gson.Gson;
import com.google.gson.JsonElement;


import org.w3c.dom.Text;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;

import activity.example.com.day.com.bawei.bean.Bean;
import activity.example.com.day.com.bawei.bean.Bean2;
import activity.example.com.day.com.bawei.bean.Data;

public class Main2Activity extends AppCompatActivity {
    private ListView lv;
    private String urll;
    private Gson gson;
    List<Data> list = new ArrayList<Data>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        lv = (ListView)findViewById(R.id.lv);
        ass();
    }
    public String ass(){
        new Thread(){
            private StringBuilder builder;
            @Override
            public void run() {
                super.run();
                try {
                    URL url = new URL("http://api.expoon.com/AppNews/getNewsList/type/1/p/1");
                    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                    int code = urlConnection.getResponseCode();
                    if(code==200) {
                        InputStream inputStream = urlConnection.getInputStream();
                        BufferedReader bf = new BufferedReader(new InputStreamReader(inputStream));
                        builder = new StringBuilder();
                        String s = "";
                        while ((s = bf.readLine()) != null) {
                            builder.append(s);
                        }
                        Message message = Message.obtain();
                        message.obj=builder.toString();
                        Handler.sendMessage(message);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }.start();
        return null;
    }
    Handler Handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            gson = new Gson();
            Bean bean = gson.fromJson((String) msg.obj, Bean.class);
            List<Data> data = bean.getData();
            for(int i=0;i<data.size();i++){
                list.add(new Data(data.get(i).getNews_id(),data.get(i).getNews_summary(),data.get(i).getNews_title(),data.get(i).getPic_url()));
            }
            lv.setAdapter(new Adapter());
        }
    };

    class Adapter extends BaseAdapter{
        @Override
        public int getCount() {
            return list.size();
        }
        @Override
        public Object getItem(int i) {
            return list.get(i);
        }
        @Override
        public long getItemId(int i) {
            return i;
        }
        class ViewHowder{
            ImageView img;
            TextView tv;
        }
        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            Data data = list.get(i);
            ViewHowder howder = new ViewHowder();
            if(view==null){
                view=View.inflate(Main2Activity.this,R.layout.lv,null);
                howder.img  = (ImageView) view.findViewById(R.id.imageView2);
                howder.tv = (TextView)view.findViewById(R.id.textView);
                view.setTag(howder);
            }else{
                howder = (ViewHowder) view.getTag();
            }
            howder.tv.setText(data.getNews_title());
            new MyASynctask(howder.img).execute(data.getPic_url());
            return view;
        }
    }
    class MyASynctask extends AsyncTask<String,Void,Bitmap>{
        private ImageView img;
        private Bitmap bitmap;
        public MyASynctask(ImageView img){
            this.img=img;
        }
        @Override
        protected Bitmap doInBackground(String... strings) {
            try {
                URL url = new URL(strings[0]);
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                InputStream inputStream = urlConnection.getInputStream();
                bitmap = BitmapFactory.decodeStream(inputStream);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return bitmap;
        }
        @Override
        protected void onPostExecute(Bitmap bitmap) {
            super.onPostExecute(bitmap);
            img.setImageBitmap(bitmap);
        }
    }
}