Chris Lambacher <[EMAIL PROTECTED]> writes:
if iter does not override the __nonzero__ method from object, the while loop will always evaluate iter as true. The documenation says that listtstore.remove sets iter to the next valid row so the original unless it is the last row in which case the iter is invalidated. so the while loop needs to check if iter is valid using liststore.iter_is_valid:
while self.lstore.iter_is_valid(iter): self.lstore.remove(iter)
if remove invalidates iter rather than setting it to the next line, the documentation needs to be updated.
I think the docs are wrong and remove(iter) won't advance the iter. In the C API, iter is a reference parameter. This is a handy C idiom but it's pretty hostile to bindings. In order to advance the iter you need to call iter_next().
You have to be careful though, because this won't work:
# don't do this while self.lstore.iter_is_valid(iter): iter = self.lststore.iter_next(iter)
The iter_next() method returns None when applied to an iter to the last row, so ultimately when you run off the end of the list you will get an error because None isn't a GtkTreeIter:
>>> self.lstore.iter_is_valid(None) Traceback (most recent call last): File "<stdin>", line 1, in ? TypeError: iter should be a GtkTreeIter
The original "while iter:" test is good and it's almost always what you want. In normal use your iters will come from get_iter_first(), iter_next() and append() and the like. The iters should always be valid or None unless you remove the row they refer to. Since you're the one removing the row you know when the iter isn't valid -- there's rarely a need to test.
# A slow way to do self.lstore.clear() iter = self.lstore.get_iter_first() while iter: next = self.lstore.iter_next(iter) self.lstore.remove(iter) iter = next
Thanks to everyone that posted replies. I found that both of these work:
while iter and self.lstore.iter_is_valid(iter):
self.lstore.remove(iter) while iter:
next = self.lstore.iter_next(iter)
self.lstore.remove(iter)
iter = nextIn the end I used the second one, because the reference manual says that iter_is_valid(iter) is slow and should only be used for debugging. I can confirm thought at self.lstore.remove(iter) does move iter on to point at the next row.
Thanks again, Stuart
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