ListView以分页的方式从服务器获取数据

客户端:

package cn.com.xiebiao.listview;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

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

public class MainActivity extends Activity {
    private String serverAddr="";
    private ListView listView;
    //是否分页
    private boolean is_divpage;
    //loading dialog
    private ProgressDialog dialog;
    //用于保存接收的数据
    List<String> data=new ArrayList<String>();
    //页数
    private static int pageNo=1;

    MyAdapter myAdapter=new MyAdapter();

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

        listView.setOnScrollListener(new AbsListView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(AbsListView absListView, int i) {
                System.out.println("----onScrollStateChanged>>"+i);
                //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
                if(is_divpage&& i==0){
                    //手指划到最底部并松开，即表示请求下次数据
                    is_divpage=true;
                    Toast.makeText(MainActivity.this,"下一页",Toast.LENGTH_SHORT).show();
                    new MyTask().execute(serverAddr+pageNo);
                }
            }

            @Override
            public void onScroll(AbsListView absListView, int i, int i2, int i3) {
                if((i+i2)==i3){
                    //滑到最底部
                    is_divpage=true;
                }else {
                    is_divpage=false;
                }
            }
        });
    }

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

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

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

            //更新data
            myAdapter.bindDate(data);

            if(pageNo==1){
                listView.setAdapter(myAdapter);
            }
            myAdapter.notifyDataSetChanged();
            pageNo++;
            //关闭progressDialog
            dialog.dismiss();
        }
    }

    class MyAdapter extends BaseAdapter {
        private List<String> list;
        private TextView textView;

        MyAdapter() {
        }

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

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

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

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

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            System.out.println("--->>getView中i=" + i);
            if (view == null) {
                textView=new TextView(MainActivity.this);
            } else {
                textView=(TextView)view;
            }
            textView.setText(list.get(i));
            textView.setTextSize(30);
            return textView;
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android=""
    package="cn.com.xiebiao.listview" >
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

package cn.com.xiebiao.listview;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;

import java.io.IOException;

/**
 * Created by vibexie on 3/23/15.
 */
public class HttpUtils {

    public static String sendPostMethod(String path,String encoding){
        String result=null;
        HttpClient httpClient=new DefaultHttpClient();
        HttpPost httpPost=new HttpPost(path);
        try {
            HttpResponse httpResponse=httpClient.execute(httpPost);
            if(httpResponse.getStatusLine().getStatusCode()==200){
                result= EntityUtils.toString(httpResponse.getEntity(),encoding);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            httpClient.getConnectionManager().shutdown();
        }

        return result;
    }
}

package cn.com.xiebiao.listview;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

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

/**
 * Created by vibexie on 3/23/15.
 */
public class JsonTools {
    public static List<String> parseJsonList(String jsonString){
        List<String> list=new ArrayList<String>();
        try {
            JSONObject jsonObject=new JSONObject(jsonString);
            JSONArray jsonArray=jsonObject.getJSONArray("data");
            for(int i=0;i<jsonArray.length();i++){
                list.add(jsonArray.getString(i));
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return list;
    }
}

服务器端：

package cn.com.xiebiao.dividePage;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONSerializer;


/**
 *
 * Title  : DividePageServlet.java
 * Company: ZhenBot
 * Author : Vibe Xie  @
 * Time   : Mar 23, 2015 10:30:03 AM
 * Copyright: Copyright (c) 2015
 * 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
 */
@WebServlet("/dividePageServlet")
public class DividePageServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    //private static int currentPage;//当前页
    /**
     * @see HttpServlet#HttpServlet()
     */
    public DividePageServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doPost(request, response);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        PrintWriter printWriter=response.getWriter();

        //获取资源
        DataSource dataSource=new DataSource();
        List<String> date=dataSource.getDataSource();

        //获取客户端的请求页码
        String pageNo=request.getParameter("pageNo");

        int currentPage=1;//当前页
        //请求页码非空的时候设定当前页为请求页
        if(pageNo!=null){
            currentPage=Integer.parseInt(pageNo);
        }

        DividePageUtil dividePageUtil=new DividePageUtil(25, date.size(), currentPage);
        int fromIndex=dividePageUtil.getFromIndex();
        int toIndex=dividePageUtil.getToIndex();

        //当前页的数据
        List<String> subData=date.subList(fromIndex, toIndex);
        //将当前页的数据包装成json数据
        Map<String, Object> map=new HashMap<String, Object>();
        map.put("data", subData);
        String jsonString=JSONSerializer.toJSON(map).toString();

        //返回给客户端
        printWriter.print(jsonString);
        printWriter.flush();
        printWriter.close();
    }

}

package cn.com.xiebiao.dividePage;

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

public class DataSource {
    private List<String> list;

    public DataSource() {
        // TODO Auto-generated constructor stub
    }

    public List<String> getDataSource(){
        list=new ArrayList<String>();
        for(int i=1;i<=500;i++){
            list.add("data"+i);
        }
        return list;
    }
}

package cn.com.xiebiao.dividePage;

/**
 *
 * Title  : DividePageUtil.java
 * Company: ZhenBot
 * Author : Vibe Xie  @
 * Time   : Mar 23, 2015 10:52:38 AM
 * Copyright: Copyright (c) 2015
 * Description:分页工具类
 */
public class DividePageUtil {
    private int pageSize;//每页条数
    private int dataSize;//数据的总条数
    private int currentPage;//当前页
    private int pageCount;//总页数

    public DividePageUtil(int pageSize,int dateSize,int currentPage) {
        // TODO Auto-generated constructor stub
        this.pageSize=pageSize;
        this.dataSize=dateSize;
        this.setCurrentPage(currentPage);
    }

    public int getPageSize() {
        return pageSize;
    }
    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }
    public int getDataSize() {
        return dataSize;
    }
    public void setDataSize(int dataSize) {
        this.dataSize = dataSize;
    }
    public int getCurrentPage() {
        return currentPage;
    }

    //设置当前页
    public void setCurrentPage(int currentPage){
        int activePage= currentPage<=0 ? 1 :currentPage;
        activePage= currentPage>getPageCount() ? getPageCount() : activePage;
        this.currentPage=activePage;
    }

    //获取总页数
    public int getPageCount() {
        pageCount=dataSize/pageSize;
        if((dataSize%pageSize)!=0){
            pageCount++;
        }
        return dataSize==0 ? 1 : pageCount;
    }
    public void setPageCount(int pageCount) {
        this.pageCount = pageCount;
    }

    //获取指定页的起始索引
    public int getFromIndex(){
        return (currentPage-1)*pageSize;
    }
    //获取指定页的结束索引
    public int getToIndex(){
        return (currentPage*pageSize);
    }
}