xlistview上拉刷新和下拉加載

package com.example.a09_xlistview_demo;

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.example.a09_xlistview_demo.view.XListView;
import com.google.gson.Gson;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class MainActivity extends AppCompatActivity implements XListView.IXListViewListener {
private List<DataDataBean.DataBean>list=new ArrayList<>();
    //定義一個大的集合,,,裝當前頁面所有的數據

    private XListView xListView;
    private Myadapter myAdapter;
    private int page_num = 1;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        xListView = (XListView) findViewById(R.id.x_list_view);
        //設置支持上拉還是下拉
        xListView.setPullRefreshEnable(true);
        xListView.setPullLoadEnable(true);
        //監聽事件
        xListView.setXListViewListener(this);
        getDataFromNet();

    }

    private void getDataFromNet() {
        AsyncTask<Void, Void, String> asyncTask = new AsyncTask<Void, Void, String>() {
            @Override
            protected String doInBackground(Void... voids) {
                String path = "http://www.yulin520.com/a2a/impressApi/news/mergeList?pageSize=10&page=1";
                try {
                    URL url=new URL(path);
                    HttpURLConnection connection= (HttpURLConnection) url.openConnection();
                   connection.setRequestMethod("GET");
                    connection.setConnectTimeout(5000);
                    connection.setReadTimeout(5000);
                    int responseCode = connection.getResponseCode();
                    if (responseCode==200){
                        InputStream inputStream = connection.getInputStream();
                        String json=streamToString(inputStream,"utf_8");
                        return json;

                    }

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


                return null;
            }

            @Override
            protected void onPostExecute(String s) {
                Gson gson=new Gson();
                DataDataBean dataDataBean = gson.fromJson(s, DataDataBean.class);
                list.addAll(dataDataBean.getData());

                setAdapter();
                //停止加載
                xListView.stopLoadMore();
            }
        };
        asyncTask.execute();

    }
    /**
     * 設置適配器
     */
    private void setAdapter() {
        if (myAdapter==null){
             myAdapter=new Myadapter(MainActivity.this,list);
              xListView.setAdapter(myAdapter);

        }else {
               myAdapter.notifyDataSetChanged();
        }

    }
    /**
     * 這是下拉刷新的時候自動調用的方法
     *
     * 例如,,,下拉刷新的時候我們讓他請求下一頁的內容
     */
    @Override
    public void onRefresh() {
          page_num++;
        AsyncTask<Void, Void, String> asyncTask = new AsyncTask<Void, Void, String>() {
            @Override
            protected String doInBackground(Void... voids) {
                String path = "http://www.yulin520.com/a2a/impressApi/news/mergeList?pageSize=10&page="+page_num;
                try {
                    URL url = new URL(path);

                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                    //設置
                    connection.setRequestMethod("GET");
                    connection.setReadTimeout(5000);
                    connection.setConnectTimeout(5000);

                    //獲取
                    int responseCode = connection.getResponseCode();
                    if (responseCode == 200){
                        InputStream inputStream = connection.getInputStream();

                        String json = streamToString(inputStream,"utf-8");

                        return json;
                    }

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

                return null;

            }

            @Override
            protected void onPostExecute(String s) {
              Gson gson=new Gson();
                DataDataBean dataBean = gson.fromJson(s, DataDataBean.class);
                //下拉刷新的數據需要添加在大集合的最前邊
                list.addAll(0,dataBean.getData());
                setAdapter();
                //停止刷新
                xListView.stopRefresh();
                //System.currentTimeMillis()....當前時間的long類型的值
                Date date=new Date(System.currentTimeMillis());
                //格式化....yyyy-MM-dd HH:mm
                SimpleDateFormat simpleDateFormat = new SimpleDateFormat("HH:mm");
                //設置本次刷新的時間
                xListView.setRefreshTime(simpleDateFormat.format(date));
            }
        };
   asyncTask.execute();

    }
    /**
     * 這是上拉加載的時候調用的方法
     *
     * 上拉加載更多......例如:讓他請求第一頁數據
     */
    @Override
    public void onLoadMore() {
        getDataFromNet();

    }
    private String streamToString(InputStream inputStream, String charset) {
        try {
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream,charset);

            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            String s = null;
            StringBuilder builder = new StringBuilder();
            while ((s = bufferedReader.readLine()) != null){
                builder.append(s);
            }

            bufferedReader.close();
            return builder.toString();

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

        return  null;
    }




}