NullPointerException试图在Android中使用OAuth发送电子邮件。

I'm trying to send an e-mail using Google's Gmail API and OAuth 2.0. I manage to get what appears to be a valid SMTPTransport (not entirely sure it's valid), but when I go to try and send an e-mail I get a NullPointerException on the line where sendMessage occurs. Actually, the exception doesn't happen exactly on that line. What is weird is that in Eclipse the current line in the debugger goes back to the first line in the sendMail method and then returns to the calling client with a NullPointerException. I can't tell what is causing the null exception. The smtpTransport and msg variables are not null:I'm trying to send an e-mail using Google's Gma