Android提高第八篇之SQLite分页读取

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;//显示分页数据    
    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> 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>();    
    
        // 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 });    
    
        // 添加并且显示    
        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  map = new HashMap();    
            map.put("ItemText", "No." + String.valueOf(i));  
    
            lstPageID.add(map);    
        }    
        saPageID.notifyDataSetChanged();    
    }    
}