ListView以分页的方式从服务器获取数据

2210阅读　0评论2015-03-23　vibe26
分类：Android平台

客户端:

MainActivity.java

  1. package cn.com.xiebiao.listview;
  2. import android.app.Activity;
  3. import android.app.ProgressDialog;
  4. import android.os.AsyncTask;
  5. import android.os.Bundle;
  6. import android.view.View;
  7. import android.view.ViewGroup;
  8. import android.widget.AbsListView;
  9. import android.widget.BaseAdapter;
  10. import android.widget.ListView;
  11. import android.widget.TextView;
  12. import android.widget.Toast;

  14. import java.util.ArrayList;
  15. import java.util.List;

  17. public class MainActivity extends Activity {
  18.     private String serverAddr="";
  19.     private ListView listView;
  20.     //是否分页
  21.     private boolean is_divpage;
  22.     //loading dialog
  23.     private ProgressDialog dialog;
  24.     //用于保存接收的数据
  25.     List<String> data=new ArrayList<String>();
  26.     //页数
  27.     private static int pageNo=1;

  29.     MyAdapter myAdapter=new MyAdapter();

  31.     @Override
  32.     protected void onCreate(Bundle savedInstanceState) {
  33.         super.onCreate(savedInstanceState);
  34.         setContentView(R.layout.activity_main);
  35.         listView = (ListView) this.findViewById(R.id.listView);
  36.         //设置ProgressDialog属性
  37.         dialog=new ProgressDialog(this);
  38.         dialog.setTitle("提示");
  39.         dialog.setMessage("loading...");
  40.         //初始的时候加载第一页
  41.         new MyTask().execute(serverAddr+pageNo);

  43.         listView.setOnScrollListener(new AbsListView.OnScrollListener() {
  44.             @Override
  45.             public void onScrollStateChanged(AbsListView absListView, int i) {
  46.                 System.out.println("----onScrollStateChanged>>"+i);
  47.                 //onScrollStateChanged再手指离开屏幕的瞬间调用，所以晚于onScroll的最后一次调用
  48.                 if(is_divpage&& i==0){
  49.                     //手指划到最底部并松开，即表示请求下次数据
  50.                     is_divpage=true;
  51.                     Toast.makeText(MainActivity.this,"下一页",Toast.LENGTH_SHORT).show();
  52.                     new MyTask().execute(serverAddr+pageNo);
  53.                 }
  54.             }

  56.             @Override
  57.             public void onScroll(AbsListView absListView, int i, int i2, int i3) {
  58.                 if((i+i2)==i3){
  59.                     //滑到最底部
  60.                     is_divpage=true;
  61.                 }else {
  62.                     is_divpage=false;
  63.                 }
  64.             }
  65.         });
  66.     }

  68.     //异步任务，再网络上读取数据
  69.     class MyTask extends AsyncTask<String,Void,List<String>>{
  70.         @Override
  71.         protected void onPreExecute() {
  72.             super.onPreExecute();
  73.             dialog.show();
  74.         }

  76.         @Override
  77.         protected List<String> doInBackground(String... strings) {
  78.             String jsonString=HttpUtils.sendPostMethod(strings[0],"utf-8");
  79.             List<String> list=JsonTools.parseJsonList(jsonString);
  80.             return list;
  81.         }

  83.         @Override
  84.         protected void onPostExecute(List<String> strings) {
  85.             super.onPostExecute(strings);
  86.             data.addAll(strings);

  88.             //更新data
  89.             myAdapter.bindDate(data);

  91.             if(pageNo==1){
  92.                 listView.setAdapter(myAdapter);
  93.             }
  94.             myAdapter.notifyDataSetChanged();
  95.             pageNo++;
  96.             //关闭progressDialog
  97.             dialog.dismiss();
  98.         }
  99.     }

  101.     class MyAdapter extends BaseAdapter {
  102.         private List<String> list;
  103.         private TextView textView;

  105.         MyAdapter() {
  106.         }

  108.         public void bindDate(List<String> list){
  109.             this.list = list;
  110.         }

  112.         @Override
  113.         public int getCount() {
  114.             System.out.println("--->>getCount中size=" + list.size());
  115.             return list.size();
  116.         }

  118.         @Override
  119.         public Object getItem(int i) {
  120.             System.out.println("--->>getItem中i=" + i);
  121.             return i;
  122.         }

  124.         @Override
  125.         public long getItemId(int i) {
  126.             System.out.println("--->>getItemID中i=" + i);
  127.             return 5;
  128.         }

  130.         @Override
  131.         public View getView(int i, View view, ViewGroup viewGroup) {
  132.             System.out.println("--->>getView中i=" + i);
  133.             if (view == null) {
  134.                 textView=new TextView(MainActivity.this);
  135.             } else {
  136.                 textView=(TextView)view;
  137.             }
  138.             textView.setText(list.get(i));
  139.             textView.setTextSize(30);
  140.             return textView;
  141.         }
  142.     }
  143. }

AndroidMainfest.xml

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <manifest xmlns:android=""
  3.     package="cn.com.xiebiao.listview" >
  4. <uses-permission android:name="android.permission.INTERNET"></uses-permission>
  5.     <application
  6.         android:allowBackup="true"
  7.         android:icon="@mipmap/ic_launcher"
  8.         android:label="@string/app_name"
  9.         android:theme="@style/AppTheme" >
  10.         <activity
  11.             android:name=".MainActivity"
  12.             android:label="@string/app_name" >
  13.             <intent-filter>
  14.                 <action android:name="android.intent.action.MAIN" />

  16.                 <category android:name="android.intent.category.LAUNCHER" />
  17.             </intent-filter>
  18.         </activity>
  19.     </application>

  21. </manifest>


HttpUtil.java

  1. package cn.com.xiebiao.listview;

  3. import org.apache.http.HttpResponse;
  4. import org.apache.http.client.HttpClient;
  5. import org.apache.http.client.methods.HttpPost;
  6. import org.apache.http.impl.client.DefaultHttpClient;
  7. import org.apache.http.util.EntityUtils;

  9. import java.io.IOException;

  11. /**
  12.  * Created by vibexie on 3/23/15.
  13.  */
  14. public class HttpUtils {

  16.     public static String sendPostMethod(String path,String encoding){
  17.         String result=null;
  18.         HttpClient httpClient=new DefaultHttpClient();
  19.         HttpPost httpPost=new HttpPost(path);
  20.         try {
  21.             HttpResponse httpResponse=httpClient.execute(httpPost);
  22.             if(httpResponse.getStatusLine().getStatusCode()==200){
  23.                 result= EntityUtils.toString(httpResponse.getEntity(),encoding);
  24.             }
  25.         } catch (IOException e) {
  26.             e.printStackTrace();
  27.         }finally {
  28.             httpClient.getConnectionManager().shutdown();
  29.         }

  31.         return result;
  32.     }
  33. }

JsonTool.java

  1. package cn.com.xiebiao.listview;

  3. import org.json.JSONArray;
  4. import org.json.JSONException;
  5. import org.json.JSONObject;

  7. import java.util.ArrayList;
  8. import java.util.List;

  10. /**
  11.  * Created by vibexie on 3/23/15.
  12.  */
  13. public class JsonTools {
  14.     public static List<String> parseJsonList(String jsonString){
  15.         List<String> list=new ArrayList<String>();
  16.         try {
  17.             JSONObject jsonObject=new JSONObject(jsonString);
  18.             JSONArray jsonArray=jsonObject.getJSONArray("data");
  19.             for(int i=0;i<jsonArray.length();i++){
  20.                 list.add(jsonArray.getString(i));
  21.             }
  22.         } catch (JSONException e) {
  23.             e.printStackTrace();
  24.         }
  25.         return list;
  26.     }
  27. }

服务器端：

DividePageServlet.java

  1. package cn.com.xiebiao.dividePage;

  3. import java.io.IOException;
  4. import java.io.PrintWriter;
  5. import java.util.HashMap;
  6. import java.util.List;
  7. import java.util.Map;

  9. import javax.servlet.ServletException;
  10. import javax.servlet.annotation.WebServlet;
  11. import javax.servlet.http.HttpServlet;
  12. import javax.servlet.http.HttpServletRequest;
  13. import javax.servlet.http.HttpServletResponse;

  15. import net.sf.json.JSONSerializer;


  18. /**
  19.  *
  20.  * Title : DividePageServlet.java
  21.  * Company: ZhenBot
  22.  * Author : Vibe Xie @
  23.  * Time : Mar 23, 2015 10:30:03 AM
  24.  * Copyright: Copyright (c) 2015
  25.  * Description: 服务器端将数据进行分页，客户端发送页码请求，服务器返回对应页的json数据
  26.  */
  27. @WebServlet("/dividePageServlet")
  28. public class DividePageServlet extends HttpServlet {
  29.     private static final long serialVersionUID = 1L;
  30.     //private static int currentPage;//当前页
  31.     /**
  32.      * @see HttpServlet#HttpServlet()
  33.      */
  34.     public DividePageServlet() {
  35.         super();
  36.         // TODO Auto-generated constructor stub
  37.     }

  39.     /**
  40.      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
  41.      */
  42.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  43.         // TODO Auto-generated method stub
  44.         doPost(request, response);
  45.     }

  47.     /**
  48.      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
  49.      */
  50.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  51.         // TODO Auto-generated method stub
  52.         request.setCharacterEncoding("utf-8");
  53.         response.setCharacterEncoding("utf-8");
  54.         response.setContentType("text/html;charset=utf-8");
  55.         PrintWriter printWriter=response.getWriter();
  56.         
  57.         //获取资源
  58.         DataSource dataSource=new DataSource();
  59.         List<String> date=dataSource.getDataSource();
  60.         
  61.         //获取客户端的请求页码
  62.         String pageNo=request.getParameter("pageNo");
  63.         
  64.         int currentPage=1;//当前页
  65.         //请求页码非空的时候设定当前页为请求页
  66.         if(pageNo!=null){
  67.             currentPage=Integer.parseInt(pageNo);
  68.         }
  69.         
  70.         DividePageUtil dividePageUtil=new DividePageUtil(25, date.size(), currentPage);
  71.         int fromIndex=dividePageUtil.getFromIndex();
  72.         int toIndex=dividePageUtil.getToIndex();
  73.         
  74.         //当前页的数据
  75.         List<String> subData=date.subList(fromIndex, toIndex);
  76.         //将当前页的数据包装成json数据
  77.         Map<String, Object> map=new HashMap<String, Object>();
  78.         map.put("data", subData);
  79.         String jsonString=JSONSerializer.toJSON(map).toString();

  81.         //返回给客户端
  82.         printWriter.print(jsonString);
  83.         printWriter.flush();
  84.         printWriter.close();
  85.     }

  87. }

DataSource.java

  1. package cn.com.xiebiao.dividePage;

  3. import java.util.ArrayList;
  4. import java.util.List;

  6. public class DataSource {
  7.     private List<String> list;
  8.     
  9.     public DataSource() {
  10.         // TODO Auto-generated constructor stub
  11.     }
  12.     
  13.     public List<String> getDataSource(){
  14.         list=new ArrayList<String>();
  15.         for(int i=1;i<=500;i++){
  16.             list.add("data"+i);
  17.         }
  18.         return list;
  19.     }
  20. }

DividePageUtil.java

  1. package cn.com.xiebiao.dividePage;

  3. /**
  4.  *
  5.  * Title : DividePageUtil.java
  6.  * Company: ZhenBot
  7.  * Author : Vibe Xie @
  8.  * Time : Mar 23, 2015 10:52:38 AM
  9.  * Copyright: Copyright (c) 2015
  10.  * Description:分页工具类
  11.  */
  12. public class DividePageUtil {
  13.     private int pageSize;//每页条数
  14.     private int dataSize;//数据的总条数
  15.     private int currentPage;//当前页
  16.     private int pageCount;//总页数
  17.     
  18.     public DividePageUtil(int pageSize,int dateSize,int currentPage) {
  19.         // TODO Auto-generated constructor stub
  20.         this.pageSize=pageSize;
  21.         this.dataSize=dateSize;
  22.         this.setCurrentPage(currentPage);
  23.     }
  24.     
  25.     public int getPageSize() {
  26.         return pageSize;
  27.     }
  28.     public void setPageSize(int pageSize) {
  29.         this.pageSize = pageSize;
  30.     }
  31.     public int getDataSize() {
  32.         return dataSize;
  33.     }
  34.     public void setDataSize(int dataSize) {
  35.         this.dataSize = dataSize;
  36.     }
  37.     public int getCurrentPage() {
  38.         return currentPage;
  39.     }
  40.     
  41.     //设置当前页
  42.     public void setCurrentPage(int currentPage){
  43.         int activePage= currentPage<=0 ? 1 :currentPage;
  44.         activePage= currentPage>getPageCount() ? getPageCount() : activePage;
  45.         this.currentPage=activePage;
  46.     }
  47.     
  48.     //获取总页数
  49.     public int getPageCount() {
  50.         pageCount=dataSize/pageSize;
  51.         if((dataSize%pageSize)!=0){
  52.             pageCount++;
  53.         }
  54.         return dataSize==0 ? 1 : pageCount;
  55.     }
  56.     public void setPageCount(int pageCount) {
  57.         this.pageCount = pageCount;
  58.     }
  59.     
  60.     //获取指定页的起始索引
  61.     public int getFromIndex(){
  62.         return (currentPage-1)*pageSize;
  63.     }
  64.     //获取指定页的结束索引
  65.     public int getToIndex(){
  66.         return (currentPage*pageSize);
  67.     }
  68. }



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