There are two ways to send email from android application directly without any intent
- using SMTP & JavaMail API follow the link for details
- using Webservice( for example PHP script ) so there is a server side code and you hit that URL with param like ( name,subject etc) so basically PHP code send mail at the end and it's very easy to use .
Personally, I suggest you use Webservice because it's simpler than first approach.
** Edit: You can save email in sharedpreferences
or database and fetch it from there when you try to send mail rather than hardcoding it to avoid theft email risk.(directly putting mail address inside code)
Anyway you can prevent other from getting your full source code
.See this answer