问题
Why do CursorAdapter subclasses requires the primary key to be necessarily _id ?
Isn't there a method to override, or something like that, to change this behaviour ?
I have read this trick many times, and I am aware of that ... I just want to understand better ! Thanks
回答1:
Why does CursorAdapter subclasses requires the primary key to be necessarily _id ?
It turns around and provides that value in various places, such as the long id value in getView().
Isn't there a method to override, or something like that, to change this behaviour ?
No, sorry. If you do not have a suitable column, just add ROWID AS _ID to your list of columns to return in rawQuery():
SELECT ROWID AS _id, foo, bar FROM really_important_table ORDER BY foo;
ROWID is automatically added to all SQLite tables by default, and is a unique integer, which fits the _id requirements nicely.
来源：https://stackoverflow.com/questions/23068199/sqlite-primary-key-field-name-cursoradapter-subclasses