Question

I see that AbstractWindowedCursor has methods to check the type of a column. This is a great convenience! But when I look at the CursorWindow class, I see that the documentation for isBlob() says:

Checks if a field contains either a blob or is null.

So, does this mean that if I run this check on, say, a String column that contains a NULL value, will it return true? If so, this means I can’t rely on that method as a guaranteed type check.

Answer 1

Checks if a field contains either a blob or is null.

So, does this mean that if I run this check on, say, a String column that contains a NULL value, will it return true?

I haven’t tried it myself but I suspect the answer is ‘yes’ (either that or there’s a typo in the docs).

However, if you run isNull() first and that returns ‘true’ then you know that it isn’t going to be possible to tell what the ‘column’ type is anyway (the isXxxx methods check the type of data the ‘field’ contains not the ‘column’ type).

But if you run isNull() first and it returns ‘false’ then run isBlob(), if it returns true the field contains a blob.