Android Tutorial

By : Ketan Bhimani

354 

rowsAffected = sqlDB.update(
TrackPointDatabase.TRACKPOINTS_TABLE,
values, _ID + “=” + id, null);
} else {
rowsAffected = sqlDB.update(
TrackPointDatabase.TRACKPOINTS_TABLE,
values, selection + “ and “ + _ID + “=”

• id, selectionArgs);
  }
  break;
  default:
  throw new IllegalArgumentException(
  “Unknown or Invalid URI “ + uri);
  }
  getContext().getContentResolver().notifyChange(uri, null);
  return rowsAffected;
  }

In this block of code, a writable SQLiteDatabase instance is

retrieved and the Uri type the user passed in is determined with a

call to the match() method of the UriMatcher. No checking of values

or parameters is performed here. However, to block updates to a

specific Uri, such as a Uri affecting multiple rows or a match on

TRACKPOINT_ID, java.lang.UnsupportedOperationException can be

thrown to indicate this. In this example, though, trust is placed in

the user of this content provider.

After calling the appropriate update() method, the system is

notified of the change to the URI with a call to the notifyChange()

method. This tells any observers of the URI that data has possibly

changed. Finally, the affected number of rows is returned, which is

information conveniently returned from the call to the update()

method.

Implementing the delete() Method

Now it’s time to clean up the database. The following is a sample

implementation of the delete() method. It doesn’t check to see if