I want to detect if a new incoming mail is available without falling back to the system that I have to poll the mail-server eg. once a minute.
I this possible using B4A?
Something that implements (part of) an IMAP-client?
It doesn't matter whether you use SMTP or IMAP. You will need to poll the server for new messages every few minutes
The other option is to send a push message from the server (with the standard GCM service).