ListView滑动分页，并加载部分数据

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由于要使用SimpleAdapter，所以要新建一个布局文件tab_info.xml

<?xml version="1.0" encoding="utf-8"?>

<TableLayout

xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/mylayout"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<TextView

android:id="@+id/id"

android:textSize="30px"

android:layout_height="wrap_content"

android:layout_width="50px"/>

<TextView

android:id="@+id/name"

android:textSize="30px"

android:layout_height="wrap_content"

android:layout_width="130px"/>

<TextView

android:id="@+id/birthday"

android:textSize="30px"

android:layout_height="wrap_content"

android:layout_width="180px"/>

</TableRow>

</TableLayout>

在main.xml中：

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout

xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/mylayout"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

</LinearLayout>

在MySQLiteDemo.java中

package com.li.sqlite;

import java.util.List;

import java.util.Map;

import android.app.Activity;

import android.database.sqlite.SQLiteOpenHelper;

import android.os.Bundle;

import android.view.Gravity;

import android.widget.AbsListView;

import android.widget.AbsListView.OnScrollListener;

import android.widget.LinearLayout;

import android.widget.LinearLayout.LayoutParams;

import android.widget.ListView;

import android.widget.SimpleAdapter;

import android.widget.TextView;

public class MySQLiteDemo extends Activity {

private ListView listView ;

private SimpleAdapter simpleAdapter = null ;

private LinearLayout loadLayout = null ; // 读取的脚标的视图

private TextView loadInfo = null ; // 进行信息提示

private List<Map<String,Object>> all = null ;

private LayoutParams layoutParams = new LinearLayout.LayoutParams(

LinearLayout.LayoutParams.FILL_PARENT,

LinearLayout.LayoutParams.WRAP_CONTENT); // 表示新组件的布局参数

private SQLiteOpenHelper helper = null ;

private LinearLayout mylayout = null ;

private int currentPage = 1 ;

private int lineSize = 15 ;

private int allRecorders = 0 ;

private int pageSize = 1 ; // 默认在一共只有1页

private int lastItem = 0 ; // 保存最后一项

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

super.setContentView(R.layout.main);

this.mylayout = (LinearLayout) super.findViewById(R.id.mylayout) ;

this.loadLayout = new LinearLayout(this) ; // 定义脚标的线性布局管理器

this.loadInfo = new TextView(this) ; // 文本组件

this.loadInfo.setText("数据加载中ing...") ; // 定义提示文字

this.loadInfo.setGravity(Gravity.CENTER) ; // 文字居中显示

this.loadInfo.setTextSize(30.0f) ; // 文字大小

this.loadLayout.addView(this.loadInfo,this.layoutParams) ; // 增加组件

this.loadLayout.setGravity(Gravity.CENTER) ;

this.showAllData() ; // 数据显示

this.pageSize = (this.allRecorders + this.lineSize - 1)

/ this.lineSize; // 计算总页数

System.out.println("pageSize = " + this.pageSize) ;

System.out.println("allRecorders = " + this.allRecorders);

}

private void showAllData(){ // 读取全部的数据

MySQLiteDemo.this.helper = new MyDatabaseHelper(MySQLiteDemo.this);

MytabCursor cur = new MytabCursor( // 实例化查询

MySQLiteDemo.this.helper.getReadableDatabase()) ; // 取得SQLiteDatabase对象

this.allRecorders = cur.getCount() ; // 取得全部记录数

this.listView = new ListView(MySQLiteDemo.this) ;

MySQLiteDemo.this.all = cur.find(MySQLiteDemo.this.currentPage,MySQLiteDemo.this.lineSize) ;

this.listView.addFooterView(this.loadLayout) ; // 增加读取数据的布局文件

this.simpleAdapter = new SimpleAdapter(MySQLiteDemo.this, // 上下文对象

MySQLiteDemo.this.all, // 所有要操作的数据

R.layout.tab_info, // 布局管理器

new String[] { "id", "name", "birthday" }, // map中的key

new int[] { R.id.id, R.id.name, R.id.birthday }) ;

this.listView.setAdapter(this.simpleAdapter); // 布局管理中的id

this.listView.setOnScrollListener(new OnScrollListenerImpl()) ;

this.mylayout.addView(listView) ;

}

private class OnScrollListenerImpl implements OnScrollListener{

public void onScroll(AbsListView view, int firstVisibleItem,

int visibleItemCount, int totalItemCount) {

MySQLiteDemo.this.lastItem = firstVisibleItem + visibleItemCount - 1 ; // 统计是否到最后

}

public void onScrollStateChanged(AbsListView view, int scrollState) {

if (MySQLiteDemo.this.lastItem == MySQLiteDemo.this.simpleAdapter

.getCount()// 已经是最底部

&& MySQLiteDemo.this.currentPage < MySQLiteDemo.this.pageSize // 还有数据没读取完

&& scrollState == OnScrollListener.SCROLL_STATE_IDLE ) { // 不再滑动

MySQLiteDemo.this.currentPage ++ ;

MySQLiteDemo.this.listView.setSelection(MySQLiteDemo.this.lastItem) ; // 设置显示位置

MySQLiteDemo.this.appendData() ; // 增加数据

}

private void appendData(){ // 增加数据

MytabCursor cur = new MytabCursor( // 实例化查询

MySQLiteDemo.this.helper.getReadableDatabase()) ; // 取得SQLiteDatabase对象

List<Map<String, Object>> newData = cur.find(this.currentPage,

this.lineSize);

this.all.addAll(newData) ; // 集合改变

this.simpleAdapter.notifyDataSetChanged() ; // 通知记录改变

}

在MytabCursor.java中

package com.li.sqlite;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

public class MytabCursor {

private static final String TABLENAME = "mytab" ;

private SQLiteDatabase db = null ;

public MytabCursor(SQLiteDatabase db) {

this.db = db ;

}

public int getCount() { // 返回记录数

int count = 0;

String sql = "SELECT COUNT(id) FROM " + TABLENAME; // 查询SQL

Cursor result = this.db.rawQuery(sql, null);

for (result.moveToFirst(); !result.isAfterLast(); result.moveToNext()) { // 采用循环的方式检索数据

count = result.getInt(0);

}

return count;

}

public List<Map<String,Object>> find(int currentPage,int lineSize){

List<Map<String,Object>> all = new ArrayList<Map<String,Object>>() ;

String sql = "SELECT id,name,birthday FROM " + TABLENAME

+ " LIMIT ?,?";

String args[] = new String[] {

String.valueOf((currentPage - 1) * lineSize),

String.valueOf(lineSize) }; // 是设置参数

Cursor result = this.db.rawQuery(sql, args); // 执行查询语句

for (result.moveToFirst(); !result.isAfterLast(); result.moveToNext()) { // 采用循环的方式检索数据

Map<String,Object> map = new HashMap<String,Object>() ;

map.put("id", result.getInt(0)) ;

map.put("name", result.getString(1)) ;

map.put("birthday",result.getString(2)) ;

all.add(map) ;

}

this.db.close() ;

return all ;

}

在MyDatabaseHelper.java中

package com.li.sqlite;

//数据库的辅助操作类

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

public class MyDatabaseHelper extends SQLiteOpenHelper {

private static final String DATABASENAME = "liyewen.db" ;

private static final int DATABASERVERSION = 1 ; // 设置数据库的版本

private static final String TABLENAME = "mytab" ;

public MyDatabaseHelper(Context context) { // 用户最关心的也肯定只是Context

super(context, DATABASENAME, null, DATABASERVERSION);

}

@Override

public void onCreate(SQLiteDatabase db) { // 创建数据表

String sql = "CREATE TABLE " + TABLENAME + "("

+ "id INTEGER PRIMARY KEY ," // 在SQLite中设置为Integer、PRIMARY KEY则ID自动增长

+ "name VARCHAR(50) NOT NULL ,"

+ "birthday DATE NOT NULL" + ")";

db.execSQL(sql) ; // 执行SQL

System.out.println("****************** 创建：onCreate()。");

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

String sql = "DROP TABLE IF EXISTS " + TABLENAME ;

db.execSQL(sql) ;

System.out.println("****************** 更新：onUpgrade()。");

this.onCreate(db) ;

}