Runtime error ( IllegalArgumentException) when using SimpleCursorAdapter - column '_id' does not exist

Question

I try to get some db values and display them in a listview.

Here is my code:

public class SearchCustomer extends Activity{    

private DBCreater dbHelpe         


        

Answer 1

Per the documentation for CursorAdapter, of which SimpleCursorAdapter is a subclass :

The Cursor must include a column named "_id" or this class will not work.

If your table already has a column named "_id", then just include this in the query's projection (the requested columns).

String selectQuery = "select _id, customer_name, ... from Customer";

If your table doesn't have an "_id" column, you can instead alias the "rowid" that all SQLite tables have by default (excepting those explicitly created without one).

String selectQuery = "select rowid as _id, customer_name, ... from Customer";

The same can be done even if you're not using raw SQL. For example, in a query() call:

mCursor = db.query("Customer", new String[] {"rowid as _id", "customer_name", ...}, ...);

You can, of course, alias another column you might already have, if it's equivalent to an "_id". Do note, though, that you must use the alias name - i.e., "_id" - with the Cursor, should you be manually retrieving values from it.