SQLite在Android中使用

程序内使用SQLite数据库是通过SQLiteOpenHelper进行操作

1.       自己写个类继承SQLiteOpenHelper,重写以下3个方法

public void onCreate(SQLiteDatabase db)

{//创建数据库时的操作，如建表}

 

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)

       {

           //版本更新的操作

       }

2.    通过SQLiteOpenHelper的getWritableDatabase()获得一个SQLiteDatabase数据库，以后的操作都是对SQLiteDatabase进行操作。

3.       对得到的SQLiteDatabase对象进行增，改，删，查等操作。

代码

package cx.myNote;   import android.content.ContentValues; import android.content.Context; import android.content.Intent; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper;   //DBOptions for login public class DBOptions {        private static final String DB_NAME = "notes.db";        private static final String DB_CREATE="create table logininf(name text,pwd text)";        public class DBHelper extends SQLiteOpenHelper        {                 public DBHelper(Context context) {                      super(context,DB_NAME, null, 1);                      }                 @Override               public void onCreate(SQLiteDatabase db) {                      // TODO Auto-generated method stub                      //建表                  db.execSQL(DB_CREATE);               }                             @Override               public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {                      // TODO Auto-generated method stub                      db.execSQL("drop table if exists logininf");                      onCreate(db);               }                      }        private Context context;        private SQLiteDatabase db;        private DBHelper dbHelper;        public  DBOptions(Context context)        {               this.context = context;               dbHelper = new DBHelper(context);               db=dbHelper.getReadableDatabase();                      }   //自己写的方法，对数据库进行操作        public String getName()        {                             Cursor cursor = db.rawQuery("select name from logininf", null);               cursor.moveToFirst();               return cursor.getString(0);            }        public int changePWD(String oldP,String pwd)        {               ContentValues values = new ContentValues();               values.put("pwd", pwd);               return db.update("logininf", values,"pwd="+oldP, null);        } }