【Android】Handler的应用（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 block
e.printStackTrace();
}
};
};
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.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() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// TODO Auto-generated method stub
try {
JSONObject jsonObject = (JSONObject) mData.get(position);
Toast.makeText(ListViewPage.this,
jsonObject.getString("title"), Toast.LENGTH_SHORT)
.show();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.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
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
page++;
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"));
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);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return list.length();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
@Override
public 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view
oneView = 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”
