Android實現基於滑動的SQLite數據分頁加載技術(附demo源碼下載)

本文實例講述了Android實現基於滑動的SQLite數據分頁加載技術。分享給大家供大家參考，具體如下：

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; //默認在第一頁
 private static final int lineSize = 7; //每次顯示數 
 private int allRecorders = 0; //全部記錄數
 private int pageSize = 1; //默認共一頁
 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);
  //創建一個角標線性布局用來顯示"正在加載"
  loadLayout = new LinearLayout(this);
  loadLayout.setGravity(Gravity.CENTER);
  //定義一個文本顯示“正在加載”
  loadInfo = new TextView(this); 
  loadInfo.setText("正在加載...");
  loadInfo.setGravity(Gravity.CENTER);
  //增加組件 
  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();
 }
 /**
  * 讀取全部數據
  */
 public void showAllData(){
  service = new DatabaseService(this);
  allRecorders = service.getCount();
  //計算總頁數
  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; //統計是否到最後
 }
 @Override
 public void onScrollStateChanged(AbsListView view, int scorllState) {
  System.out.println("進入滾動界面了");
  //是否到最底部並且數據沒讀完
  if(lastItem == baseAdapter.getCount() 
    && currentPage < pageSize //不再滾動
    && scorllState == OnScrollListener.SCROLL_STATE_IDLE){
   currentPage ++;
   //設置顯示位置
   listView.setSelection(lastItem);
   //增加數據
   appendDate(); 
  }
 }
 /**
  * 增加數據
  */
 private void appendDate(){
  ArrayList<String> additems = service.getAllItems(currentPage, lineSize);
  baseAdapter.setCount(baseAdapter.getCount() + additems.size());
  //判斷，如果到了最末尾則去掉“正在加載”
  if(allRecorders == baseAdapter.getCount()){
   listView.removeFooterView(loadLayout);
  }
  items.addAll(additems);
  //通知記錄改變
  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;
  }
 }
}

完整實例代碼點擊此處本站下載。

更多關於Android相關內容感興趣的讀者可查看本站專題：《Android操作SQLite數據庫技巧總結》、《Android操作json格式數據技巧總結》、《Android數據庫操作技巧總結》、《Android編程之activity操作技巧總結》、《Android文件操作技巧匯總》、《Android編程開發之SD卡操作方法匯總》、《Android開發入門與進階教程》、《Android資源操作技巧匯總》、《Android視圖View技巧總結》及《Android控件用法總結》

希望本文所述對大家Android程序設計有所幫助。