在我的活動我有例如爲什麼使用SQLiteOpenHelper而不是SQLiteDatabase?
SQLiteDatabase db = openOrCreateDatabase(Preferences.DB_NAME, Context.MODE_PRIVATE, null);
db.execSQL("CREATE TABLE IF NOT EXISTS data (id INTEGER PRIMARY KEY, value VARCHAR)");
Cursor dbResult = db.rawQuery("SELECT value FROM data", null);
// do sometning with cursors
dbResult.close();
db.close();
什麼用SQLiteOpenHelper像
DatabaseHelper helper = new DatabaseHelper(this);
SQLiteDatabase db = helper.getWriteableDatabase();
SQLiteDatabase db_2 = helper.getReadableDatabase();
Cursor dbResult = db_2.rawQuery("SELECT value FROM data", null);
// do sometning with cursors
dbResult.close();
helper.close();
類利益本身
public class DatabaseHelper extends SQLiteOpenHelper {
public DatabaseHelper(Context context) {
super(context, Preferences.DB_NAME, null, Preferences.DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String query = "CREATE TABLE IF NOT EXISTS data (id INTEGER PRIMARY KEY, value VARCHAR)";
db.execSQL(query);
db.close();
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
傑克說的是對的。請記住'SQLiteOpenHelper'實際上是從'SQLiteDatabase'類中調用靜態方法的。 – dnkoutso