Bad indentation when pasting into VIM

Sometimes with vim pasting you can visually select the copied code and press

=

which will reformat the code to your settings.

You may just have vim set to convert spaces to tabs. Try setting:

tabstop=4 shiftwidth=4 expandtab

in your .vimrc. Also, before you paste, just do

:set paste

Then insert, paste, then

:set nopaste

Here is a good writeup on paste mode.