android中滑动SQLite数据库分页加载

今天用到了android中滑动SQlit数据库分页加载技术，写了个测试工程，将代码贴出来和大家交流一下：

MainActivity

package com.example.testscrollsqlite;

import java.util.ArrayList;

import android.app.ActionBar.LayoutParams;
import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.Adapter;
import android.widget.BaseAdapter;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;

public class MainActivity extends Activity implements OnScrollListener{
	private TextView loadInfo;
	private ListView listView;
	private LinearLayout loadLayout;
	private ArrayList<String> items;
	private DatabaseService service;
	private int currentPage = 1; //默认在第一页
	private static final int lineSize = 7;    //每次显示数
	private int allRecorders = 0;  //全部记录数
	private int pageSize = 1;  //默认共一页
	private int lastItem;
	private Aleph0 baseAdapter;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		listView = (ListView) findViewById(R.id.listview);
		//创建一个角标线性布局用来显示"正在加载"
		loadLayout = new LinearLayout(this);
		loadLayout.setGravity(Gravity.CENTER);
		//定义一个文本显示“正在加载”
		loadInfo = new TextView(this);
		loadInfo.setText("正在加载...");
		loadInfo.setGravity(Gravity.CENTER);
		//增加组件
		loadLayout.addView(loadInfo, new LayoutParams(
				LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
		//增加到listView底部
		listView.addFooterView(loadLayout);
		listView.setOnScrollListener(this);

		showAllData();

	}

	/**
	 * 读取全部数据
	 */
	public void showAllData(){
		service = new DatabaseService(this);
		allRecorders = service.getCount();
		//计算总页数
		pageSize = (allRecorders + lineSize -1) / lineSize;
		System.out.println("allRecorders =  " + allRecorders);
		System.out.println("pageSize  =  " + pageSize);
		items = service.getAllItems(currentPage, lineSize);
		for(int i=0; i<items.size(); i++){
			System.out.println(items.get(i));
		}
		baseAdapter = new Aleph0();
		listView.setAdapter(baseAdapter);
	}

	@Override
	public void onScroll(AbsListView view, int firstVisible, int visibleCount,
			int totalCount) {
		lastItem = firstVisible + visibleCount - 1; //统计是否到最后

	}

	@Override
	public void onScrollStateChanged(AbsListView view, int scorllState) {
		System.out.println("进入滚动界面了");
		//是否到最底部并且数据没读完
		if(lastItem == baseAdapter.getCount()
				&& currentPage < pageSize    //不再滚动
				&& scorllState == OnScrollListener.SCROLL_STATE_IDLE){
			currentPage ++;
			//设置显示位置
			listView.setSelection(lastItem);
			//增加数据
			appendDate();
		}

	}

	/**
	 * 增加数据
	 */
	private void appendDate(){
		ArrayList<String> additems = service.getAllItems(currentPage, lineSize);
		baseAdapter.setCount(baseAdapter.getCount() + additems.size());
		//判断，如果到了最末尾则去掉“正在加载”
		if(allRecorders == baseAdapter.getCount()){
			listView.removeFooterView(loadLayout);
		}
		items.addAll(additems);
		//通知记录改变
		baseAdapter.notifyDataSetChanged();
	}

	class Aleph0 extends BaseAdapter {
		int count = lineSize; /* starting amount */

		public int getCount() {
			return count;
		} 

		public void setCount(int count){
			this.count = count;
		}

		public Object getItem(int pos) {
			return pos;
		}

		public long getItemId(int pos) {
			return pos;
		}

		public View getView(int pos, View v, ViewGroup p) {
			TextView view = new TextView(MainActivity.this);
			view.setTextSize(60);
			if(items != null){
				view.setText(items.get(pos));
			}else{
				view.setText(pos);
			}
			return view;
		}
	}

}

MyDBOpenHelper

package com.example.testscrollsqlite;

import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.provider.BaseColumns;

public class MyDBOpenHelper extends SQLiteOpenHelper {
	private static final String DATABASE_NAME = "merit.db";
	private static final int DATABASE_VERSION = 1;
	private static final String TABLE_NAME = "database";
	public static final String FIELD_TITLE = "title";

	/**
	 *
	 * @param context
	 *            上下文
	 * @param name
	 *            数据库的名字
	 * @param factory
	 *            结果集游标工厂(一般使用默认)
	 * @param version
	 *            数据库的版本号（必须version>=1）
	 */
	public MyDBOpenHelper(Context context) {
		super(context, DATABASE_NAME, null, DATABASE_VERSION);
	}

	/**
	 * 在MyDBOpenHelper第一次new出来时，系统会调用onCreate方法
	 */
	@Override
	public void onCreate(SQLiteDatabase db) {
		System.out.println("我被调用了");

		String sql = "Create table " + TABLE_NAME + "(" + BaseColumns._ID
				+ " integer primary key autoincrement," + FIELD_TITLE
				+ " text )";
		db.execSQL(sql);
		initDatabase(db);

	}

	// 向数据库的表中插入一些数据。
	private void initDatabase(SQLiteDatabase db) {
		ContentValues cv = new ContentValues();
		cv.put("title", "cctv1 news");
		db.insert(TABLE_NAME, null, cv);

		cv.clear();
		cv.put("title", "cctv2 news");
		db.insert(TABLE_NAME, null, cv);

		cv.clear();
		cv.put("title", "cctv3 news");
		db.insert(TABLE_NAME, null, cv);

		cv.clear();
		cv.put("title", "cctv4 news");
		db.insert(TABLE_NAME, null, cv);

		cv.clear();
		cv.put("title", "cctv5 news");
		db.insert(TABLE_NAME, null, cv);

		cv.clear();
		cv.put("title", "cctv6 news");
		db.insert(TABLE_NAME, null, cv);

		cv.clear();
		cv.put("title", "cctv7 news");
		db.insert(TABLE_NAME, null, cv);

		cv.clear();
		cv.put("title", "cctv8 news");
		db.insert(TABLE_NAME, null, cv);

		cv.clear();
		cv.put("title", "cctv9 news");
		db.insert(TABLE_NAME, null, cv);

		cv.clear();
		cv.put("title", "cctv10 news");
		db.insert(TABLE_NAME, null, cv);

		cv.clear();
		cv.put("news_title", "guangshui tv");
		db.insert(TABLE_NAME, null, cv);
	}

	@Override
	public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
		// TODO Auto-generated method stub

	}

}

DatabaseService

package com.example.testscrollsqlite;

import java.util.ArrayList;

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

public class DatabaseService { 

	private Context mContext;
	private MyDBOpenHelper dbHelper;

	public DatabaseService(Context context) {
		// TODO Auto-generated constructor stub
		mContext = context;
		dbHelper = new MyDBOpenHelper(mContext);
	}

	// 添加
	public void insert(String title) {
		SQLiteDatabase db = dbHelper.getWritableDatabase();
		String sql = "insert into database(title) values(?)";
		db.execSQL(sql, new String[] { title });
	}

	// 删除
	public void delete(String title) {
		SQLiteDatabase db = dbHelper.getWritableDatabase();
		String sql = "delete from database where title = ?";
		db.execSQL(sql, new String[] { title });
	}

	// 查找
	public ArrayList<String> find(int id) {
		SQLiteDatabase db = dbHelper.getWritableDatabase();
		String sql = "select * from database where _id = ? ";
		Cursor c = db.rawQuery(sql, new String[] { String.valueOf(id) });
		ArrayList<String> titles = new ArrayList<String>();
		if (c.moveToNext()) {
			String title = c.getString(c
					.getColumnIndexOrThrow(MyDBOpenHelper.FIELD_TITLE));
			titles.add(title);
			return titles;
		}
		// 不用忘记关闭Cursor。
		c.close();
		return null;
	}

	// 更新
	public void upDate(int id, String title) {
		SQLiteDatabase db = dbHelper.getWritableDatabase();
		String sql = "update database set title =? where _id = ?";
		db.execSQL(sql,
				new String[] { String.valueOf(title), String.valueOf(id) });
	}

	// 查询记录的总数
	public int getCount() {
		SQLiteDatabase db = dbHelper.getWritableDatabase();
		String sql = "select count(*) from database";
		Cursor c = db.rawQuery(sql, null);
		c.moveToFirst();
		int length = c.getInt(0);
		c.close();
		return length;
	}

	/**
	 * 分页查询
	 *
	 * @param currentPage 当前页
	 * @param pageSize 每页显示的记录
	 * @return 当前页的记录
	 */
	public ArrayList<String> getAllItems(int currentPage, int pageSize) {
		int firstResult = (currentPage - 1) * pageSize;
		int maxResult = currentPage * pageSize;
		SQLiteDatabase db = dbHelper.getWritableDatabase();
		String sql = "select * from database limit ?,?";
		Cursor mCursor = db.rawQuery(
				sql,
				new String[] { String.valueOf(firstResult),
						String.valueOf(maxResult) });
		ArrayList<String> items = new ArrayList<String>();
		int columnCount  = mCursor.getColumnCount();
		while (mCursor.moveToNext()) {
			String item = mCursor.getString(mCursor
					.getColumnIndexOrThrow(MyDBOpenHelper.FIELD_TITLE));
			items.add(item);

		}
		//不要关闭数据库
		return items;
	}
}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"

    android:orientation="vertical" >
    <ListView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/listview">

    </ListView>

</LinearLayout>

源代码下载http://download.csdn.net/detail/lxq_xsyu/5955673