SQLiteの使い方：データベースのOpen

SQLiteの使い方：データベースのOpenのサンプルコードです。

public class MainActivity extends AppCompatActivity {

    static final String DB = "sqlite_sample.db";
    static final int DB_VERSION = 1;
    static final String CREATE_TABLE = "create table mytable ( _id integer primary key autoincrement, date text not null, weight real not null, body_fat_percentage real not null );";
    static final String DROP_TABLE = "drop table mytable;";

    static SQLiteDatabase mydb;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
                         (中略)
        MySQLiteOpenHelper hlpr = new MySQLiteOpenHelper(getApplicationContext());
        mydb = hlpr.getWritableDatabase();
     }

     private class MySQLiteOpenHelper extends SQLiteOpenHelper { 
         public MySQLiteOpenHelper(Context c) {
             super(c, DB, null, DB_VERSION);
         }

         @Override
         public void onCreate(SQLiteDatabase db) {
             db.execSQL(CREATE_TABLE);
         }
 
         @Override
         public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
             db.execSQL(DROP_TABLE);
             onCreate(db);
         }
     }
}