For those of you trying to create a "flexible" email reader, I suggest doing the following.
Firstly, instead of going through each part of the email and decoding it, I suggest you go in a specific order.
1) First go through all the parts and search for the part that has subtype=='HTML'. If found, use that as your message body, else go to Step 2.
2) If HTML component not found, search all parts for subtype=='PLAIN'. If found, use that as your message body else print out an error message (this should never occur).
3) At this point, you already have the main body of the email that you should display. The next thing to do is to find all the attachments. You do this by going through all parts, searching for the parts with ifdisposition==1 (there can be multiple).
This is the way I did my email reader program and it works perfectly. I started off by using the methods recommended in a lot of webpages (i.e. going through the parts tree like 1.2.1, 1, 2, etc) but the problem is the message body is never in some fixed part! Sometimes its in 1, somtimes 1.1.2, sometimes 2, and sometimes in some totally unexpected place! So my approach was to "search" for the parts that I'm interested. Hope this helps. I also managed to crack the problem with emails containing embedded images. I will probably write a tutorial on that soon.
