Android：分页下载示例(PullToRefresh)

此篇文章注释较少（下载数据使用的是Volley），如若有不解之处，
可以参考另一篇博客（下载数据使用的是Xutils）：
《PullToRefresh下拉刷新，上拉分页，返回顶部》

package com.myapplication.newpagerrefreshlistview;

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.widget.ListView;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.handmark.pulltorefresh.library.ILoadingLayout;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshListView;
import com.myapplication.newpagerrefreshlistview.VolleyUtils.MyDataUtils;
import com.myapplication.newpagerrefreshlistview.VolleyUtils.StringCallBack;
import com.myapplication.newpagerrefreshlistview.VolleyUtils.VolleyUtils;

import org.json.JSONException;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private PullToRefreshListView pullToRefreshListView;
    private String path = "http://api.fengniao.com/app_ipad/pic_bbs_list_v2." +
            "php?appImei=99000505856649&osType=Android&osVersion=4.1.1&fid=125&page=";
    //封装好的下载工具
    private VolleyUtils volleyUtils;
    private List<Bean> totallist = new ArrayList<>();
    private ListViewAdapter listViewAdapter;
    private int page = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
        getData(1);
        setPullListener();
    }

    private void init() {
        volleyUtils = new VolleyUtils();

        pullToRefreshListView = (PullToRefreshListView) findViewById(R.id.refresh_to_update_next_pager);
        //先设置拉动模式(常见3种),
        pullToRefreshListView.setMode(PullToRefreshBase.Mode.BOTH);
        //设置刷新界面,拿到刷新界面
        ILoadingLayout loadingLayout = pullToRefreshListView.getLoadingLayoutProxy(true, true);
        //设置加载时候的图片
        loadingLayout.setLoadingDrawable(getResources().getDrawable(R.mipmap.ic_launcher));
        //最近更新，一般还要设置更新时间
        loadingLayout.setLastUpdatedLabel(MyDataUtils.getCurrentDate());
        //设置刷新时候的文字
        loadingLayout.setRefreshingLabel("拼命加载中，莫捉急……");
        //设置拉动和释放时候的文字
        loadingLayout.setPullLabel("轻一点拉动，爱护屏幕……");
        loadingLayout.setRefreshingLabel("释放中……");

        listViewAdapter = new ListViewAdapter(this, totallist);
        pullToRefreshListView.setAdapter(listViewAdapter);
    }

    private void setPullListener() {
        pullToRefreshListView.setOnRefreshListener(
                new PullToRefreshBase.OnRefreshListener2<ListView>() {
                    @Override
                    public void onPullDownToRefresh(PullToRefreshBase<ListView> refreshView) {
                        //TODo 下拉时触发的事件
                        new GetDataTask().execute();//不加此行，刷新不会停止，有bug待解决
                    }

                    @Override
                    public void onPullUpToRefresh(PullToRefreshBase<ListView> refreshView) {
                        //TODO 上拉时触发的事件
                        page++;
                        getData(page);
                        new GetDataTask().execute();//不加此行，刷新不会停止，有bug待解决
                    }
                });
    }

    public void getData(int page) {
        volleyUtils.getStringData(path + page, new StringCallBack() {
            @Override
            public void getStringData(String data) {
                //TODO json解析
                //jsonToList(data);
                fastJsonToList(data);
            }
        });
    }

    List<Bean> fastJsonToList(String s) {
        if (!TextUtils.isEmpty(s)) {
            JSONObject json = JSON.parseObject(s);
            JSONArray array = json.getJSONArray("list");
            List<Bean> list = JSON.parseArray(array.toJSONString(), Bean.class);

            totallist.addAll(list);
            listViewAdapter.notifyDataSetChanged();
            if (list.size() != 0) {
                return list;
            }
        }
        return null;
    }

    List<Bean> jsonToList(String s) {
        List<Bean> list = new ArrayList<>();
        try {
            org.json.JSONObject object = new org.json.JSONObject(s);
            org.json.JSONArray array = object.getJSONArray("list");
            for (int i = 0; i < array.length(); i++) {
                org.json.JSONObject j = array.getJSONObject(i);
                String pic_url = j.getString("pic_url");
                String title = j.getString("title");
                Bean bean = new Bean();
                bean.setPic_url(pic_url);
                bean.setTitle(title);
                list.add(bean);
            }
            totallist.addAll(list);
            listViewAdapter.notifyDataSetChanged();
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return list;
    }

    private class GetDataTask extends AsyncTask<Void, Void, List<Bean>> {
        @Override
        protected List<Bean> doInBackground(Void... params) {
            try {
                Thread.sleep(4000);
            } catch (InterruptedException e) {
            }
            return totallist;
        }

        @Override
        protected void onPostExecute(List<Bean> result) {
            listViewAdapter.notifyDataSetChanged();
            pullToRefreshListView.onRefreshComplete();
            super.onPostExecute(result);
        }
    }
}

ListViewAdapter中代码：

package com.myapplication.newpagerrefreshlistview;

import android.content.Context;
import android.graphics.Bitmap;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.myapplication.newpagerrefreshlistview.VolleyUtils.BitmapCallBack;

import java.util.List;

/** * Created by Administrator on 2016/3/8. */
public class ListViewAdapter extends MyBaseAdapter<Bean> {

    public ListViewAdapter(Context context, List<Bean> list) {
        super(context, list);
    }

    @Override
    public View getItemView(int position, View convertView, ViewGroup parent) {
        final ViewHolder viewHolder;
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.item, parent, false);
            viewHolder = new ViewHolder();
            viewHolder.img = (ImageView) convertView.findViewById(R.id.iv_item_pic);
            viewHolder.txt = (TextView) convertView.findViewById(R.id.tv_item_txt);
            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }
        //数据显示
        Bean bean = list.get(position);
        viewHolder.txt.setText(bean.getTitle());
        utils.getImageBitmap(bean.getPic_url(), new BitmapCallBack() {
            @Override
            public void getBitmap(Bitmap bitmap) {
                viewHolder.img.setImageBitmap(bitmap);
            }
        });
        return convertView;
    }

    class ViewHolder {
        ImageView img;
        TextView txt;
    }
}