Android实现简单的分批加载ListView

每次滑动至底端，从数据库中获取10条数据，并加载于ListView中

数据库

package com.example.listviewbatchloading;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class PersonDb extends SQLiteOpenHelper {

public PersonDb(Context context) {
   super(context, "creature", null, 1);
   // TODO Auto-generated constructor stub
 }

@Override
 public void onCreate(SQLiteDatabase db) {
   // TODO Auto-generated method stub
   db.execSQL("create table people(_id integer primary key autoincrement,name char,number char)");
 }

@Override
 public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
   // TODO Auto-generated method stub
   db.execSQL("drop table people");
   onCreate(db);
 }

}

数据库的业务封装，其中获取更多数据的是核心代码

package com.example.listviewbatchloading;

/**
* 数据库的业务封装类
*/

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

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

public class PersonList {

PersonDb personDb;

public PersonList(Context context){
   this.personDb = new PersonDb(context);
 }

/**
  *   获取一定条目的数据
  * @param startIndex
  *   开始取数据的位置
  * @param num
  *   取多少条数据
  */
 public List<Person> getMoreDatas(int startIndex,int num){

List<Person> list = new ArrayList<Person>();
   SQLiteDatabase db = personDb.getWritableDatabase();
   Cursor cursor = db.rawQuery("select name,number from people order by _id desc limit ?,?",
       new String[]{startIndex + "",num + ""});

while(cursor.moveToNext()){
     Person person = new Person();
     person.setName(cursor.getString(cursor.getColumnIndex("name")));
     person.setNumber(cursor.getString(cursor.getColumnIndex("number")));
     list.add(person);
   }

cursor.close();
   db.close();

return list;

}

/**
  *   添加数据库条目
  * @param name
  * @param number
  */
 public void add(String name,String number){

SQLiteDatabase db = personDb.getWritableDatabase();

ContentValues cv = new ContentValues();
   cv.put("name", name);
   cv.put("number", number);

db.insert("people", null, cv);
   db.close();
 }

}

功能实现

package com.example.listviewbatchloading;

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

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

private ListView lv ;
 private List<Person> datas = new ArrayList<Person>();
 private static int PERPAGE = 10; //每页加载数目
 private static final int FINISH = 0;//数据加载完成
 private List<Person> moreDatas;//每次加载的数据
 private MyAdapter adapter;
 private PersonList personList ;

//若数据较多，耗时较长，数据加载完成时，发送FINISH至handler，并通知ListView更新数据
 private Handler handler = new Handler(){
   public void handleMessage(android.os.Message msg) {

switch (msg.what) {
     case FINISH:
       if (moreDatas.size() != 0) {
         System.out.println(moreDatas.toString());
         adapter.notifyDataSetChanged();
       }else {
         Toast.makeText(MainActivity.this, "没有更多数据", Toast.LENGTH_SHORT).show();
       }
       break;

default:
       break;
     }

};
 };

@Override
 protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);
   initView();
   initData();
   initEvent();
 }
 /**
  *   为ListView添加滚动监听事件，但滚动至最后一行时，加载更多数据
  */
 private void initEvent() {
   lv.setOnScrollListener(new OnScrollListener() {

@Override
     public void onScrollStateChanged(AbsListView view, int scrollState) {
       // TODO Auto-generated method stub
       if (scrollState == OnScrollListener.SCROLL_STATE_IDLE) {
         int lastVisiblePosition = lv.getLastVisiblePosition();
         if (lastVisiblePosition == datas.size() - 1) {
           initData();
           System.out.println("加载更多数据");
         }
       }
     }

@Override
     public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
       // TODO Auto-generated method stub

}
   });
 }

private void initView() {

setContentView(R.layout.activity_main);

lv = (ListView) findViewById(R.id.lv);
   personList = new PersonList(getApplicationContext());
   adapter = new MyAdapter();
   lv.setAdapter(adapter);
 }

/**
  * 在子线程中加载数据，避免主线程阻塞
  */
 private void initData() {
   new Thread() {

public void run() {

// 加载更多数据
       moreDatas = personList.getMoreDatas(datas.size(), PERPAGE);

datas.addAll(moreDatas);// 把一个容器的所有数据加进来
       // 取数据完成，发消息通知取数据完成
       handler.obtainMessage(FINISH).sendToTarget();

};
   }.start();
 }

private class ItemView{
   private TextView tv_name;
   private TextView tv_num;
 }

/**
  *   ListView的适配器
  * @author lian
  *
  */
 private class MyAdapter extends BaseAdapter{

@Override
   public int getCount() {
     // TODO Auto-generated method stub
     return datas.size();
   }

@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) {

ItemView itemView = null;
     if (convertView == null) {
       itemView = new ItemView();
       convertView = View.inflate(getApplicationContext(), R.layout.item_lv, null);
       itemView.tv_name = (TextView) convertView.findViewById(R.id.tv_name);
       itemView.tv_num = (TextView) convertView.findViewById(R.id.tv_num);
       convertView.setTag(itemView);
     }else {
       itemView = (ItemView) convertView.getTag();
     }

Person person = datas.get(position);
     itemView.tv_name.setText(person.getName());
     itemView.tv_num.setText(person.getNumber());

return convertView;
   }

}

}

其他Person的JavaBean，以及布局文件，不在赘述