Android提高之SQLite分页读取实现方法

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://scheR_406_11845@as.android.com/apk/res/android"
 android:layout_height="wrap_content" android:paddingBottom="4dip"
 android:layout_width="fill_parent">
 <TextView android:layout_width="wrap_content"
 android:layouT_Below="@+id/ItemImage" android:layout_height="wrap_content"
 android:text="TextView01" android:layout_centerHorizontal="true"
 android:id="@+id/ItemText">
 </TextView>
</RelativeLayout> 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://scheR_406_11845@as.android.com/apk/res/android"
 android:orientation="vertical" android:layout_width="fill_parent"
 android:layout_height="fill_parent">
 <Button android:layout_height="wrap_content"
 android:layout_width="fill_parent" android:id="@+id/btncreatedb"
 android:text="创建数据库"></Button>
 <Button android:layout_height="wrap_content"
 android:layout_width="fill_parent" android:text="插入一串实验数据" android:id="@+id/btnInsertRec"></Button>
 <Button android:layout_height="wrap_content" android:id="@+id/btnClose"
 android:text="关闭数据库" android:layout_width="fill_parent"></Button>
 <EditText android:text="@+id/EditText01" android:id="@+id/EditText01"
 android:layout_width="fill_parent" android:layout_height="256dip"></EditText>
 <GridView android:id="@+id/gridview" android:layout_width="fill_parent"
 android:layout_height="32dip" android:numcolumns="auto_fit"
 android:columnWidth="40dip"></GridView>
</LinearLayout>

package com.testsqlite; 
import java.util.ArrayList; 
import java.util.HashMap; 
import android.app.Activity; 
import android.database.cursor; 
import android.database.sqlException; 
import android.database.sqlite.sqliteDatabase; 
import android.os.bundle; 
import android.util.Log; 
import android.view.View; 
import android.widget.AdapterView; 
import android.widget.AdapterView.onItemClickListener; 
import android.widget.button; 
import android.widget.EditText; 
import android.widget.GridView; 
import android.widget.SimpleAdapter; 
public class testsqlite extends Activity { 
  /** Called when the activity is first created. */ 
  Button btncreatedb,btnInsert,btnClose; 
  EditText edtsql;//@L_450_32@分页数据 
  sqliteDatabase db; 
  int id;//添加记录时的id累加标记，必须全局 
  static final int PageSize=10;//分页时，每页的数据总数 
  private static final String table_NAME = "stu"; 
  private static final String ID = "id"; 
  private static final String NAME = "name"; 
  SimpleAdapter saPagEID;// 分页栏适配器 
  ArrayList<HashMap<String,String>> lstPagEID;// 分页栏的数据源，与PageSize和数据总数相关 
  @Override 
  public void onCreate(Bundle savedInstanceStatE) { 
    super.onCreate(savedInstanceStatE); 
    setContentView(R.layout.main); 
    btncreatedb = (Button) this.findViewById(R.id.btncreatedb); 
    btncreatedb.setOnClickListener(new ClickEvent()); 
    btnInsert = (Button) this.findViewById(R.id.btnInsertRec); 
    btnInsert.setOnClickListener(new ClickEvent()); 
    btnClose = (Button) this.findViewById(R.id.btnClosE); 
    btnClose.setOnClickListener(new ClickEvent()); 
    edtsql=(EditText)this.findViewById(R.id.EditText01); 
    GridView gridview = (GridView) findViewById(R.id.gridview);//分页栏控件 
    // 生成动态数组，并且转入数据 
    lstPagEID = new ArrayList<HashMap<String,String>>(); 
    // 生成适配器的ImageItem <====> 动态数组的元素，两者一一对应 
    saPagEID = new SimpleAdapter(testsqlite.this,// 没什么解释 
        lstPagEID,// 数据来源 
        R.layout.pagebuttons,//XML实现 
        new String[] { "ItemText" },new int[] { R.id.ItemText }); 
 
    // 添加并且@L_450_32@ 
    gridview.setAdapter(saPagEID); 
    // 添加消息处理 
    gridview.setOnItemClickListener(new OnItemClickListener(){ 
      @Override 
      public void onItemClick(AdapterView<?> arg0,View arg1,int arg2,long arg3) { 
        LoadPage(arg2);//根据所选分页读取对应的数据 
      } 
    }); 
  } 
  class ClickEvent implements View.onClickListener { 
    @Override 
    public void onClick(View v) { 
      if (v == btncreatedb) { 
        createdb(); 
      } else if (v == btnInsert) { 
        InsertRecord(16);//插入16条记录 
        refreshPage(); 
      }else if (v == btnClosE) { 
        db.close(); 
      } 
    } 
  } 
  /* 
   * 读取指定ID的分页数据 
   * sql:SELEct * FROM tABLE_NAME Limit 9 Offset 10; 
   * 表示从TABLE_NAME表获取数据，跳过10行，取9行 
   */ 
  void LoadPage(int pagEID) 
  { 
    String sql= "SELEct * from " + TABLE_NAME +  
    " Limit "+String.valueOf(PageSizE)+ " Offset " +String.valueOf(pagEID*PageSizE); 
    cursor rec = db.rawQuery(sql,null); 
    settitle("当前分页的数据总数:"+String.valueOf(rec.getCount())); 
    // 取得字段名称 
    String title = ""; 
    int colCount = rec.getcolumnCount(); 
    for (int i = 0; i < colCount; i++) 
      title = title + rec.getcolumnName(i) + "   "; 
    // 列举出所有数据 
    String content=""; 
    int recCount=rec.getCount(); 
    for (int i = 0; i < recCount; i++) {//定位到一条数据 
      rec.moveToPosition(i); 
      for(int ii=0;ii<colCount;ii++)//定位到一条数据中的每个字段 
      { 
        content=content+rec.getString(ii)+"   "; 
      } 
      content=content+"/r/n"; 
    } 
     
    edtsql.setText(title+"/r/n"+content);//@L_450_32@出来 
    rec.close(); 
  } 
  /* 
   * 在内存创建数据库和数据表 
   */ 
  void createdb() { 
    // 在内存创建数据库 
    db = sqliteDatabase.create(null); 
    Log.e("DB Path",db.getPath()); 
    String amount = String.valueOf(databaseList().length); 
    Log.e("DB amount",amount); 
    // 创建数据表 
    String sql = "create table " + TABLE_NAME + " (" + ID 
        + " text not null," + NAME + " text not null " + ");"; 
    try { 
      db.execsql("drop table IF EXISTS " + TABLE_Name); 
      db.execsql(sql); 
    } catch (sqlException E) {} 
  } 
  /* 
   * 插入N条数据 
   */ 
  void InsertRecord(int n) { 
    int @R_956_10586@l = id + n; 
    for (; id < @R_956_10586@l; id++) { 
      String sql = "insert into " + TABLE_NAME + " (" + ID + "," + NAME 
          + ") values('" + String.valueOf(id) + "','test');"; 
      try { 
        db.execsql(sql); 
      } catch (sqlException E) { 
      } 
    } 
  } 
  /* 
   * 插入之后刷新分页 
   */ 
  void refreshPage() 
  { 
    String sql = "SELEct count(*) from " + TABLE_NAME; 
    cursor rec = db.rawQuery(sql,null); 
    rec.moveToLast(); 
    long recSize=rec.getLong(0);//取得总数 
    rec.close(); 
    int pageNum=(int)(recSize/PageSizE) + 1;//取得分页数 
     
    lstPagEID.clear(); 
    for (int i = 0; i < pageNum; i++) { 
      HashMap<String,String> map = new HashMap<String,String>(); 
      map.put("ItemText","No." + String.valueOf(i));
      lstPagEID.add(map); 
    } 
    saPagEID.notifyDataSetChanged(); 
  } 
}