AndroidDemo.rar

package com.gggeye.android; import java.io.FileNotFoundException; import android.app.Activity; import android.content.ContentValues; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.graphics.Bitmap; import android.os.Bundle; import android.util.Log; public class AndroidSQLDemo extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.main); DBHelper dh = new DBHelper(this); //dh. dh.openDatabase("wuhua", true); Bitmap bit = android.graphics.BitmapFactory.decodeResource(this.getResources(), R.drawable.icon); ContentValues cv = new ContentValues (); byte[] bytes = "wuhua".getBytes(); for(int i=0; i<bytes.length; i++){ cv.put("wuhua", bytes[i]); } try{ dh.getDBInstance().execSQL("create table ren"); dh.getDBInstance().insert("ren", "hao", cv); }catch(Exception e){ Log.d("sqldemo", e.toString()); } } } class DBHelper { private SQLiteDatabase db = null; private Context ctx = null; public DBHelper(Context ctx) { this.ctx = ctx; } /** * 判断数据库是否存在 * * @param dbName * 数据库名称 * @return true存在 false不存在 */ public boolean exist(String dbName) { Log.d("sqldemo","called fun : exist()"); boolean flag = false; try { db = ctx.openDatabase(dbName, null); Log.d("sqldemo","database/" + dbName + " exist"); flag = true; } catch (FileNotFoundException e) { flag = false; Log.d("sqldemo","database/" + dbName + " not exist"); } finally { if (db != null) db.close(); db = null; } return flag; } /** * 打开数据库 * * @param dbName * 数据库名称 * @return true 打开成功 false打开失败 */ public boolean openDatabase(String dbName, boolean created) { return openDatabase(dbName, null, created); } /** * 打开数据库 * * @param dbName * 数据库名称 * @param factory * @return true 打开成功 false打开失败 */ public boolean openDatabase(String dbName, CursorFactory factory, boolean created) { Log.d("sqldemo","called fun : openDatabase()"); Log.d("sqldemo","called fun : if not exist then created " + dbName + " ? : " + created); boolean flag = false; if (exist(dbName)) { try { db = ctx.openDatabase(dbName, factory); Log.d("sqldemo","database/" + dbName + " is opened"); flag = true; } catch (FileNotFoundException e) { Log.d("sqldemo","database/" + dbName + " is not opened"); flag = false; } } else { if (created) { flag = createDatabase(dbName, 1, 0, factory); } else { flag = false; } } return flag; } /** * 创建数据库 * * @param dbName * 数据库名称 * @param version * 数据库版本 * @param mode * 模式 * @param factory * @return true 建立成功 false 建立失败 */ public boolean createDatabase(String dbName, int version, int mode, CursorFactory factory) { Log.d("sqldemo","called fun : createDatabase()"); boolean flag = false; try { db = ctx.createDatabase(dbName, version, mode, factory); Log.d("sqldemo","database/" + dbName + " is created successfully!"); flag = true; } catch (FileNotFoundException e) { Log.d("sqldemo","database/" + dbName + " can't be created"); flag = true; } return flag; } /** * 建立数据库 * * @param dbName * 数据库名称 * @return true 打开成功 false 打开失败 */ public boolean createDatabase(String dbName) { return createDatabase(dbName); } /** * 关闭数据库 * */ public void closeDatabase() { Log.d("sqldemo","close database"); if (db != null) db.close(); db = null; ctx = null; } /** * 删除表 * * @param tableName * 表名 * @return 成功则返回 表名 失败则返回null */ public String dropTable(String tableName) { Log.d("sqldemo","called fun dropTable()"); if (tableName == null) { Log.d("sqldemo","table name is error! " + tableName + " is null !"); return null; } String DROP_TABLE = "DROP TABLE IF EXISTS " + tableName; db.execSQL(DROP_TABLE); Log.d("sqldemo","table/" + tableName + " is dropped successfully"); return tableName; } /** * 取得数据库实例 * * @return 返回数据库实例 */ public SQLiteDatabase getDBInstance() { return db; } public boolean execSQL(String SQL) { boolean flag = false; Log.d("sqldemo","called fun execSQL()"); Log.d("sqldemo","SQL:" + SQL); try { db.execSQL(SQL); Log.d("sqldemo","sql exec successfully!"); flag = true; } catch (Exception e) { Log.d("sqldemo","sql exec not successfully!"); flag = false; } return flag; } }