Android应用中使用ListView来分页显示刷新的内容

package com.exampleandroid.xiong.listviewpages; 
 
public class news { 
 private string title; 
 private int id; 
 
 /** 
  * 
  * @return 返回新闻标题 
  */ 
 public string gettitle() { 
  return title; 
 } 
 
 /** 
  * 
  * @param title 
  *   设置新闻标题 
  */ 
 public void setttitle(string title) { 
  this.title = title; 
 } 
 
 /** 
  * 
  * @return 返回新闻标识 
  */ 
 public int getid() { 
  return id; 
 } 
 
 /** 
  * 
  * @param id 
  *   设置新闻标识 
  */ 
 public void setid(int id) { 
  this.id = id; 
 } 
} 

package com.exampleandroid.xiong.listviewpages; 
 
import java.util.arraylist; 
import java.util.list; 
import android.database.cursor; 
import android.database.sqlite.sqlitedatabase; 
 
public class getnews { 
 
 /** 
  * 
  * @param page 
  *   需要加载的页数 每页数据5条 
  * @param dbnews 
  *   sqliteopenhelper子类 
  * @return 返回新闻加载的数据 
  */ 
 public list<news> getlistnews(int page, dbsqlitenews dbnews) { 
  list<news> list = new arraylist<news>(); 
  string sql = "select * from tb_newstile where news_id not in(select news_id from tb_newstile limit " 
    + 5 * (page - 1) + ") limit " + 5 * page; 
  cursor cursor = dbnews.getreadabledatabase().rawquery(sql, null); 
  while (cursor.movetonext()) { 
   news news = new news(); 
   news.setttitle(cursor.getstring(1)); 
   news.setid(cursor.getint(0)); 
   list.add(news); 
  } 
  cursor.close(); 
  return list; 
 } 
 
 /** 
  * 插入100条数据用于测试 
  * 
  * @param dbnews 
  *   sqliteopenhelper子类 
  */ 
 public void insertdata(dbsqlitenews dbnews) { 
  sqlitedatabase datas = dbnews.getwritabledatabase(); 
  datas.begintransaction(); 
  try { 
   for (int i = 0; i < 100; i++) { 
    datas.execsql("insert into tb_newstile values(?,?)", 
      new object[] { i, "新闻标题" + i }); 
   } 
   datas.settransactionsuccessful(); 
  } catch (exception e) { 
   system.out.println("数据插入失败！"); 
   e.printstacktrace(); 
  } finally { 
   datas.endtransaction(); 
  } 
 
 } 
} 

package com.exampleandroid.xiong.listviewpages; 
 
import android.content.context; 
import android.database.sqlite.sqlitedatabase; 
import android.database.sqlite.sqlitedatabase.cursorfactory; 
import android.database.sqlite.sqliteopenhelper; 
 
public class dbsqlitenews extends sqliteopenhelper { 
 
 public dbsqlitenews(context context, string name, cursorfactory factory, 
   int version) { 
  super(context, name, factory, version); 
 } 
 
 // 创建数据库表 
 @override 
 public void oncreate(sqlitedatabase db) { 
  db.execsql("create table tb_newstile(news_id integer ,news_title varchar(100))"); 
 } 
 
 @override 
 public void onupgrade(sqlitedatabase db, int oldversion, int newversion) { 
 
 } 
 
} 

package com.exampleandroid.xiong.listviewpages; 
 
import java.util.list; 
 
import android.app.activity; 
import android.os.bundle; 
import android.view.layoutinflater; 
import android.view.menu; 
import android.view.view; 
import android.view.view.onclicklistener; 
import android.view.viewgroup; 
import android.widget.baseadapter; 
import android.widget.button; 
import android.widget.imageview; 
import android.widget.listview; 
import android.widget.textview; 
 
public class mainactivity extends activity { 
 
 private listview newshow_list; 
 private button loadmore, adddata; 
 // listview加载的数据 
 private list<news> shownews; 
 private getnews getnews; 
 private dbsqlitenews dbnews; 
 // 加载的页数 
 private int pagecount = 1; 
 
 @override 
 protected void oncreate(bundle savedinstancestate) { 
  super.oncreate(savedinstancestate); 
  setcontentview(r.layout.activity_main); 
  newshow_list = (listview) findviewbyid(r.id.newsshow_list); 
  loadmore = (button) findviewbyid(r.id.loadmore_bt); 
  adddata = (button) findviewbyid(r.id.adddata); 
  dbnews = new dbsqlitenews(this, "new.db", null, 1); 
  getnews = new getnews(); 
  final listadpaternews listadpter=new listadpaternews(); 
  //此按钮只为添加测试数据 
  adddata.setonclicklistener(new onclicklistener() { 
 
   @override 
   public void onclick(view v) { 
    //插入数据 
    getnews.insertdata(dbnews); 
    //获取数据 
    shownews = getnews.getlistnews(pagecount, dbnews); 
    //显示数据 
    newshow_list.setadapter(listadpter); 
   } 
  }); 
  loadmore.setonclicklistener(new onclicklistener() { 
 
   @override 
   public void onclick(view v) { 
    pagecount++; 
    //将数据追加到原集合 
    shownews.addall(getnews.getlistnews(pagecount, dbnews)); 
    //刷新数据 
    listadpter.notifydatasetinvalidated(); 
   } 
  }); 
  // 第一次加载的数据 
  shownews = getnews.getlistnews(pagecount, dbnews); 
  newshow_list.setadapter(listadpter); 
 
 } 
 
 class listadpaternews extends baseadapter { 
 
  @override 
  public int getcount() { 
   return pagecount * 5; 
  } 
 
  @override 
  public object getitem(int position) { 
   return position; 
  } 
 
  @override 
  public long getitemid(int position) { 
   return position; 
  } 
 
  @override 
  public view getview(int position, view convertview, viewgroup parent) { 
   view view = layoutinflater.from(mainactivity.this).inflate( 
     r.layout.news_title, null); 
   textview txttitle = (textview) view.findviewbyid(r.id.txt_title); 
   imageview images = (imageview) view 
     .findviewbyid(r.id.showimage_title); 
   images.setbackgroundresource(r.drawable.n_me_l); 
   txttitle.settext(shownews.get(position).gettitle()); 
   return view; 
  } 
 
 } 
 
 @override 
 public boolean oncreateoptionsmenu(menu menu) { 
  getmenuinflater().inflate(r.menu.main, menu); 
  return true; 
 } 
 
} 

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" 
 xmlns:tools="http://schemas.android.com/tools" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 tools:context=".mainactivity" > 
 
 <listview 
  android:id="@+id/newsshow_list" 
  android:layout_width="match_parent" 
  android:layout_height="wrap_content" > 
 </listview> 
 
 <linearlayout 
  android:layout_width="match_parent" 
  android:layout_height="wrap_content" 
  android:layout_alignparentbottom="true" > 
 
  <button 
   android:id="@+id/adddata" 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:layout_weight="1" 
   android:text="添加数据" /> 
 
  <button 
   android:id="@+id/loadmore_bt" 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:layout_weight="1" 
   android:text="@string/loadmore" /> 
 </linearlayout> 
 
</relativelayout> 

<?xml version="1.0" encoding="utf-8"?> 
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 android:padding="15dp" 
 android:orientation="horizontal" > 
 
 <imageview 
  android:id="@+id/showimage_title" 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" 
  android:background="@drawable/n_me_l" 
  android:contentdescription="@string/imagenews" /> 
 
 <textview 
  android:id="@+id/txt_title" 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" /> 
 
</linearlayout> 

@override 
public void onscroll(abslistview view, int firstvisibleitem, 
    int visibleitemcount, int totalitemcount ) { 
 
  if (getadapter() == null){ 
    return ; 
  } 
  
  if (getadapter().getcount() == 0){ 
    return ; 
  } 
  
  int lastitemindex = firstvisibleitem + visibleitemcount; 
  if (lastitemindex >= totalitemcount){ 
    // 用户已经滑动到了listview的最后一项 
  } 

@override 
public void onscroll(abslistview view, int firstvisibleitem, 
    int visibleitemcount, int totalitemcount) { 
 
  if (getadapter() == null){ 
    return ; 
  } 
  
  if (getadapter().getcount() == 0){ 
    return ; 
  } 
  
  int lastitemindex = firstvisibleitem + visibleitemcount; 
  if (lastitemindex >= totalitemcount && ! isloading){ 
   addfooterview( footerview );//用来提示用户正在加载下一页的数据 
    isloading = true ; 
    listener.loaddata(); 
  }