listview优化加强版

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.TextView;

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

/**
 * Created by lenovo on 2017/12/1.
 */

public class MyAdapter extends BaseAdapter {
    private List<Result.NewslistBean>data;
    private Context context;

    public MyAdapter(List<Result.NewslistBean> data, Context context) {
        this.data = data;
        this.context = context;
    }

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

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

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

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        ViewHolder viewHolder;
        if (view == null) {
            view = LayoutInflater.from(context).inflate(R.layout.item, null);
            viewHolder = new ViewHolder();
            viewHolder.title= view.findViewById(R.id.text1);
            viewHolder.text= view.findViewById(R.id.description);
            viewHolder.img= view.findViewById(R.id.image);
            view.setTag(viewHolder);//绑定ViewHolder对象
        }
        else {
            viewHolder = (ViewHolder)view.getTag();//取出ViewHolder对象
        }

        viewHolder.text.setText(data.get(i).getTitle());
        viewHolder.title.setText(data.get(i).getCtime());
        new MyTask(viewHolder.img).execute(data.get(i).getPicUrl());
        return view;
    }

    /*存放控件*/
    class ViewHolder {
        public TextView title;
        public TextView text;
        public ImageView img;
    }
    class  MyTask extends AsyncTask<String,Void,Bitmap> {
        private ImageView img;

        public MyTask(ImageView img) {
            this.img = img;
        }

        //运行在后台，进行网络请求，子线程
        @Override
        protected Bitmap doInBackground(String... strings) {//...可变长类型 string....相当于 String[]

            Bitmap bitmap=null;

            try {
                //1.创建URL
                URL url=new URL(strings[0]);
                //2.打开连接
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

                //3.设置
                urlConnection.setRequestMethod("GET");
                urlConnection.setReadTimeout(5000);
                urlConnection.setConnectTimeout(5000);
                //4.判断响应码
                if(urlConnection.getResponseCode()==200){
                    //5.获取数据
                    InputStream inputStream = urlConnection.getInputStream();

                    bitmap = BitmapFactory.decodeStream(inputStream);

                }

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }

            return bitmap;
        }

        //在进行网络请求得到数据之后，要操作的事件，，解析，更新ui
        @Override
        protected void onPostExecute(Bitmap s) {
            img.setImageBitmap(s);

        }
    }
}