Android实现基于滑动的SQLite数据分页加载技术(附demo源码下载)

本文实例讲述了Android实现基于滑动的SQLite数据分页加载技术。分享给大家供大家参考，具体如下：

main.xml如下：

<menu xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:id="@+id/action_settings"
android:orderInCategory="100"
android:showAsAction="never"
android:title="@string/action_settings"/>
</menu>

MainActivity.java如下：

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;
 }
}
}

完整实例代码点击此处本站下载。

希望本文所述对大家Android程序设计有所帮助。