Android：分页下载示例(PullToRefresh)

红太狼 2022-08-21 01:06 189阅读 0赞

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》][PullToRefresh]

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;
        }
    }

[PullToRefresh]: http://blog.csdn.net/iblade/article/details/50953445