【Android】Handler应用（三）：从服务器端分页加载更新ListView

在前面两节中，我们了解了如何从服务器中加载JSON数据。

现在，我们将把服务器中的JSON数据加载更新到ListView。

并且，结合之前博文的  “动态追加分页ListView数据”的相关知识，实现将服务器中的分页JSON数据，填充到ListView中。

回顾

以BaseAdapter做适配器的ListView：http://blog.csdn.net/jueblog/article/details/12114513

ListView内数据的动态追加：http://blog.csdn.net/jueblog/article/details/12148259

Activity的实现

package com.app.myhandler;import org.json.JSONArray;import org.json.JSONException;import org.json.JSONObject;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.view.ContextMenu;import android.view.ContextMenu.ContextMenuInfo;import android.view.LayoutInflater;import android.view.MenuItem;import android.view.View;import android.widget.AdapterView;import android.widget.AdapterView.AdapterContextMenuInfo;import android.widget.ListView;import android.widget.TextView;import android.widget.Toast;import com.app.adapter.MyWeixinJSON;import com.app.util.MyApplication;import com.app.util.MyThread;/** * 点击 追加数据的ListView * @author 402-9 */public class ListViewPage extends Activity {private ListView lv;private MyWeixinJSON mJson;private JSONArray mData = new JSONArray();// JSON数据源private View view_page_footer;// 底部视图private int page = 1;// 加载页码private int totalPage;// 总数据private String url = new String("http://192.168.8.4/wt_guang.php?frm=3g&cid=100");private TextView text_page;private Handler handler = new Handler() {public void handleMessage(android.os.Message msg) {try {String result = msg.obj.toString();JSONObject object = new JSONObject(result);totalPage = (Integer) object.get("totalPage");if(mJson==null) {mData = (JSONArray) object.get("items");mJson = new MyWeixinJSON(mData, ListViewPage.this);lv.setAdapter(mJson);//为ListView绑定适配器} else {mData = MyApplication.joinJSONArray(mData, (JSONArray) object.get("items"));mJson.setList(mData);mJson.notifyDataSetChanged();}text_page.setText("下一页");} catch (JSONException e) {// TODO Auto-generated catch blocke.printStackTrace();}};};@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.weixin);lv = (ListView) findViewById(R.id.lv);new MyThread(handler, url.toString(), 1).start();view_page_footer = LayoutInflater.from(this).inflate(R.layout.view_page_footer, null);lv.addFooterView(view_page_footer);// 添加底部视图lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> parent, View view,int position, long id) {// TODO Auto-generated method stubtry {JSONObject jsonObject = (JSONObject) mData.get(position);Toast.makeText(ListViewPage.this,jsonObject.getString("title"), Toast.LENGTH_SHORT).show();} catch (JSONException e) {// TODO Auto-generated catch blocke.printStackTrace();}}});text_page = (TextView) view_page_footer.findViewById(R.id.text_page);text_page.setOnClickListener(new View.OnClickListener() {// 点击按钮 追加数据 并通知适配器@Overridepublic void onClick(View v) {// TODO Auto-generated method stubpage++;if(page<=totalPage) {text_page.setText("正在加载中...");new MyThread(handler, url+"&p="+page, 1).start();} else {text_page.setText("已是最末页...");text_page.setEnabled(false);}}});}}

mData = MyApplication.joinJSONArray(mData, (JSONArray) object.get("items"));

所调用的方法为http://blog.csdn.net/jueblog/article/details/12622423中提供的方法。

适配器的修改

package com.app.adapter;import org.json.JSONArray;import org.json.JSONObject;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;import com.app.myhandler.R;public class MyWeixinJSON extends BaseAdapter {private LayoutInflater mInflater;// 动态布局映射private JSONArray list;private Context context;//private int i = 0;public void setList(JSONArray list) {this.list = list;}public MyWeixinJSON(JSONArray list, Context context) {this.list = list;this.context = context;this.mInflater = LayoutInflater.from(context);}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn list.length();}@Overridepublic Object getItem(int position) {// TODO Auto-generated method stubreturn null;}@Overridepublic long getItemId(int position) {// TODO Auto-generated method stubreturn 0;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {// TODO Auto-generated method stub// System.out.println("正在渲染第"+position+"行  +++  "+ i++);OneView oneView;if (convertView == null) {convertView = mInflater.inflate(R.layout.item_weixin, null);// 根据布局文件实例化viewoneView = new OneView();oneView.title = (TextView) convertView.findViewById(R.id.title);// 找某个控件oneView.time = (TextView) convertView.findViewById(R.id.time);oneView.info = (TextView) convertView.findViewById(R.id.info);oneView.img = (ImageView) convertView.findViewById(R.id.img);convertView.setTag(oneView);// 把View和某个对象关联起来} else {oneView = (OneView) convertView.getTag();}JSONObject jObject = null;try {jObject = list.getJSONObject(position);// 根据position获取集合类中某行数据oneView.title.setText(jObject.get("itemID").toString());// 给该控件设置数据(数据从集合类中来)oneView.time.setText(jObject.get("price").toString());oneView.info.setText(jObject.get("title").toString());oneView.img.setBackgroundResource(R.drawable.special_spring_head2);// oneView.img.setImageDrawable(Drawable.createFromStream(new// URI(jObject.getString("pic_url"))., "src"));} catch (Exception e) {// TODO: handle exception}return convertView;}/** 把每行布局文件的各个控件包装成一个对象 */private class OneView {TextView title;TextView time;TextView info;ImageView img;}}

JSON数据

最后 瞄一眼服务器上的JSON数据：

{    "totalCount": 9,    "totalPage": 2,    "items": [        {            "itemID": "13889239752",            "title": "PEACE DOVE 正品* 真兔毛 范儿厚毛衣开衫 清库价",            "pic_url": "http://img01.taobaocdn.com/bao/uploaded/i5/T1ELuGXj0yXXbAjkA._083138.jpg",            "click_url": "http://item.taobao.com/item.htm?id=13889239752",            "price": "98.00",            "promotion_price": "0.00",            "liked": "0"        },        {            "itemID": "13357878044",            "title": "现货 呛口小辣椒11月29日香港行snidel 翻领双排扣毛呢大衣外套",            "pic_url": "http://img03.taobaocdn.com/bao/uploaded/i3/T1KTWDXipfXXXmSFDX_113804.jpg",            "click_url": "http://item.taobao.com/item.htm?id=13357878044",            "price": "278.00",            "promotion_price": "0.00",            "liked": "0"        },        {            "itemID": "12740033159",            "title": "2011新款呛口小辣椒子萱王翔貉子毛毛领军绿色工装棉服棉衣大衣",            "pic_url": "http://img01.taobaocdn.com/bao/uploaded/i1/T1WiCoXi4BXXad.Qs9_073952.jpg",            "click_url": "http://item.taobao.com/item.htm?id=12740033159",            "price": "628.00",            "promotion_price": "0.00",            "liked": "0"        },        {            "itemID": "8603809978",            "title": "圣诞款大衣 三色入",            "pic_url": "http://img01.taobaocdn.com/bao/uploaded/i1/T1GWXTXhhxXXaMGqo3_045745.jpg",            "click_url": "http://s.click.taobao.com/t_8?e=7HZ6jHSTZTlU5Xur%2B%2F50d2poSR5Ba0A%2Fi8tpiW6m04z%2BWKzb6yELcZsJq6zxF7EMTqmpst%2FNOGepsZQvjjXKR0huW7F8S1whVzYKzICAu1lT&p=mm_10009952_0_0",            "price": "165.00",            "promotion_price": "0.00",            "liked": "0"        },        {            "itemID": "10629952619",            "title": "裁诺 春装新款2012女装 韩版带帽中长款加厚卫衣 女 秋冬外套大码",            "pic_url": "http://img01.taobaocdn.com/bao/uploaded/i1/T1PASfXfpoXXc.O0vb_093452.jpg",            "click_url": "http://item.taobao.com/item.htm?id=10629952619",            "price": "158.00",            "promotion_price": "0.00",            "liked": "0"        },        {            "itemID": "9158721999",            "title": "清仓包邮 出口欧美大码超酷水洗打磨斜开襟修身加厚抓绒卫衣外套",            "pic_url": "http://img03.taobaocdn.com/bao/uploaded/i3/T12t5KXXJqXXbjSw.8_100610.jpg",            "click_url": "http://s.click.taobao.com/t_8?e=7HZ6jHSTZPhaK%2FmBeumaH2YuQWkORNRTfXSCf08v9iowvo%2F0Akhswsb9gfNlScFQL%2Bc%2Bp%2BFUQiV5QW7qQyiq%2BJQ4CS399exvrZIKVVH3ZZNULw%3D%3D&p=mm_10009952_0_0",            "price": "398.00",            "promotion_price": "0.00",            "liked": "0"        }    ]}

效果图

由于服务器JSON数据是比较随意找的，所以内容不是很适合“微信”屏幕。

不要在意这些细节、、、

程序执行的第一页：

点击下一页，将会动态追加第二页的数据

由于服务器中只有两页数据，所以当再次点击“下一页”时，会显示“已是最末页”