Android USB host-to-serial connection?

Unfortunately the library from mik3y's answer (see here: mik3y/usb-serial-for-android) seems to be long dead. It has many problems and waiting pull requests. Also the LGPL licence prevents anybody to fork it and maintain it.

But don't lose your hope, there's a working replacement and it's under the MIT licence. felHR85/UsbSerial.

EDIT: I found a maintained fork of mik3y's library. But the licence or readme is not updated, so I suppose the owner doesn't have a connection to mik3y and simply took it and improved it. I hope he won't get into any trouble because of the licence, because we need this library. See kai-morich/usb-serial-for-android

EDIT2: It seems that all of these libraries are maintained again, mik3y joined forces with kai-morich and they're working together now.

EDIT3: mik3y/usb-serial-for-android is under MIT license now. And still maintained in 2022.

usb-serial-for-android is my open source library written for exactly this need. It supports FTDI and CDC-ACM usb serial devices using Android's USB host support; no root or ADK necessary. It can talk most Arduinos.

The project is still in its early days, but the basic support has worked well enough for several projects. There is also a discussion list where you can get help.