AFAIK, there is no official app, no... I know somebody made an app once, but it was just a private person's project, personally i wouldn't enter my password in that app (but that's just my personal opinion).
Actually, talking about Bitcointalk.org app. I once found an app which allow to browse bitcointalk.org, it's not a browser, it kinda some sort of app where we can browse bitcointalk.org like an Facebook app. But I never tried to log in in that app because I don't know if it's an official app or else it would contain phishing for sure. I found it in playstore with a name of "Bitcointalk.org" and an icon of Bitcoin but now it's gone. I think it has been removed with a unknown reason.I searched in google and I found this app Bitcointalk.org Forum. This is different from what I saw in playtore back in 2017 and this app is Not Official that's why I'm not recommending this to anyone . This might contain phishing. I just included it here for additional information and knowledge about Bitcointalk app and also to warn everyone that There is no such Official App for Bitcointalk.org
Just saying.
Bitcoin talk does not have an application yet. I think the app will not be very safe to use. That is why we use the browsers.
Of course it will be safe, as long as it is an Official App of this Forum. 
