AsyncTask+defaultHttpClient = listview图片+文字展示

简述：用defaultHttpClient 获取去网络json数据，在AsyncTask中获取图片和文字，并赋值到listView，由于网络获取是费时操作所以需要在子线程中运行。

第一步：添加依赖

useLibrary ‘org.apache.http.legacy’
implementation ‘com.google.code.gson:gson:2.8.5’

第二步：初始化组件开启、子线程（布局里只有一个listview）

在UI线程开启子线程，调用AsyncTask方法，传入字符串

  new Thread(){
            @Override
            public void run() {
                super.run();
                new Myasync().execute(urlString);
            }
        }.start();

第三步：继承AsyncTask方法<传进值得类型，更新进度类型，返回值类型>

**重写onPostExecute方法在其中可更新UI

class Myasync extends AsyncTask<String,Void,String>{
        @Override
        protected String doInBackground(String... strings) {
            String json = Net.getJson(strings[0]);
            return json;
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            Gson gson = new Gson();
            ArrayList<Data> data = gson.fromJson(s, JsonData.class).getData();
            MyAdapter myAdapter = new MyAdapter(data,getActivity());
            listView.setAdapter(myAdapter);

        }
    }

第四步：配置适配器，用AsyncTask添加布局中的图片

public class MyAdapter extends BaseAdapter {
    ArrayList<Data> data;
    Context context;

    public MyAdapter(ArrayList<Data> data, Context context) {
        this.data = data;
        this.context = context;
    }

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

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        Horder horder = null;
        if(convertView==null){
            convertView = View.inflate(context, R.layout.item,null);
            horder = new Horder();
            horder.imageView = convertView.findViewById(R.id.item_image);
            horder.textView = convertView.findViewById(R.id.itmet_text);

            convertView.setTag(horder);
        }else{
            horder = (Horder) convertView.getTag();
        }

        horder.textView.setText(data.get(position).getNews_title());
        String pic_url = data.get(position).getPic_url();
        //Picasso.with(context).load(data.get(position).getPic_url()).into(horder.imageView);
        new MyAsynctask(horder.imageView).execute(pic_url);
        return convertView;
    }
    class Horder{
        ImageView imageView;
        TextView textView;
    }

    class MyAsynctask extends AsyncTask<String,Void,Bitmap>{
        ImageView iv;

        public MyAsynctask(ImageView iv) {
            this.iv = iv;
        }

        @Override
        protected Bitmap doInBackground(String... strings) {
            Bitmap bitmap = Net.getBitmap(strings[0]);
            return bitmap;
        }

        @Override
        protected void onPostExecute(Bitmap bitmap) {
            super.onPostExecute(bitmap);
            iv.setImageBitmap(bitmap);
        }
    }