请求数据的封装类

public class MyNetTask extends AsyncTask {
    private IcallBack icallBack;
    public MyNetTask(IcallBack icallBack){
        this.icallBack=icallBack;
    }

    @Override
    protected String doInBackground(String... strings) {
        StringBuilder builder=new StringBuilder();
        //1.根据url创建URL
        try {
            URL url=new URL(strings[0]);
            //2.打开连接
            HttpURLConnection conn =(HttpURLConnection) url.openConnection();
            //3.设置
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(5000);
            conn.setReadTimeout(5000);

            //4.判断结果码
            if(conn.getResponseCode()==200){
                //5.获取数据
                InputStream inputStream = conn.getInputStream();

                BufferedReader reader=new BufferedReader(new InputStreamReader(inputStream));
                String str;
                while ((str=reader.readLine())!=null){
                    builder.append(str);
                }

            }


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

        Log.d("zzz",builder.toString());
        return builder.toString();
    }

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

        //gson 显示

        //4.调用接口中方法
        icallBack.getJsonData(s);

    }
    public interface IcallBack{
        void getJsonData(String jsonStr);
    }

}

private void initPsv() {
    psv.setMode(PullToRefreshBase.Mode.BOTH);

    ILoadingLayout headerLayout = psv.getLoadingLayoutProxy(true, false);
    headerLayout.setPullLabel("下拉刷新");
    headerLayout.setReleaseLabel("放开刷新");
    headerLayout.setRefreshingLabel("正在刷新。。。");

    ILoadingLayout footerLayout = psv.getLoadingLayoutProxy(false, true);
    footerLayout.setPullLabel("上拉加载");
    footerLayout.setReleaseLabel("放开加载");
    footerLayout.setRefreshingLabel("正在加载。。。。");

    psv.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2() {
        @Override
        public void onPullDownToRefresh(PullToRefreshBase pullToRefreshBase) {
            pageIndex=1;
            url=urlPart+pageIndex;
            MyNetTask task1=new MyNetTask(new MyNetTask.IcallBack() {



                @Override
                public void getJsonData(String jsonStr) {
                    Gson gson=new Gson();
                    Result1 result1 = gson.fromJson(jsonStr, Result1.class);

                    datas.addAll(result1.getNewslist());
                    setAdapter();
                    psv.onRefreshComplete();

                }
            });
            task1.execute(url);
        }

        @Override
        public void onPullUpToRefresh(PullToRefreshBase pullToRefreshBase) {
            pageIndex++;
            url=urlPart+pageIndex;

            MyNetTask task1=new MyNetTask(new MyNetTask.IcallBack() {



                @Override
                public void getJsonData(String jsonStr) {
                    Gson gson=new Gson();
                    Result1 result1 = gson.fromJson(jsonStr, Result1.class);

                    datas.addAll(result1.getNewslist());
                    setAdapter();
                    psv.onRefreshComplete();

                }
            });
            task1.execute(url);
        }
});