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。
更多关于Android相关内容感兴趣的读者可查看本站专题:《Android操作SQLite数据库技巧总结》、《Android操作json格式数据技巧总结》、《Android数据库操作技巧总结》、《Android编程之activity操作技巧总结》、《Android文件操作技巧汇总》、《Android编程开发之SD卡操作方法汇总》、《Android开发入门与进阶教程》、《Android资源操作技巧汇总》、《Android视图View技巧总结》及《Android控件用法总结》
希望本文所述对大家Android程序设计有所帮助。
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