Using Gmail app on a public WiFi Does official Gmail app use a secure connection?

This post above discussing whatever Gmail using a secure connection, but is it relevant to a public WiFi connection? Or in public WiFi, is there a chance for hacker to steal your data even with the fact Gmail using a secure connection?
The GMail application is now a general email application. You can set it up to talk to any email account. There are two important cases:


You use the GMail application with a GMail account, for example: my.user.name@gmail.com. In this case, Google only allows secure connections. 
You access a non-GMail account using the GMail application. This may be encrypted or unencrypted depending on the configuration of server and client. You can configure this to be unencrypted, though any decent mail provider now should only allow secure connections. 


Attackers will not be able to read your data unless they can generate a valid certificate that matches your mail server address or can otherwise compromise the TLS connection. This is not impossible, but if your server and your client are up to date on security patches, this is not something you have to worry about on public wifi.