Ask HN: Is there something to connect Raspberry's WiFi from a phone?

I have a project kiosk-like Using raspberry Pi. Every time I set one up, I have to connect manually internet through wifi (using keyboard). I was wondering if there is something to do the whole thing with the phone, similar to how chromecast does it.

I heard captive portals are in the way to extinction and are harder to use due to Google restrictions in Android for security.

Any idea? How would you do it?