FTDriver is no more supported.

We are developing a new USB Serial Driver "Physicaloid Library".

Physicaloid Library is FTDriver + Arduino Writer + CP210x Driver and has simple APIs.

Android USB Serial Driver

USB Serial Driver using Android USB Host API

Java source code
no root
baudrate : 9600 - 230400 (be able to setting immediate baudrate number)
support FTDI chips (FT232RL, FT232H, FT2232C/D/HL, FT4232HL FT230X, REX-USB60F/MI(FT232BL) checked)
support any channels (FT2232X:2ch, FT4232X:4ch)
support CDC-ACM(beta)
like Arduino library's interface

Connection

Android [USB A port] --- [USB B port] FTDI Chip

Library Project
FTDriver : Driver for connecting an FTDI chip to Android USB host port
Sample Projects
FTSampleTerminal : very simple terminal
FTSerialCSV : serial communication with a Genet educational board (www.genet-nara.jp) in CSV format (Thanks for Heima Hayashida)

Fig. Connecting an Android tablet to a Genet board(FT232RL) by a USB cable.(ET2011 Forum in Japan)

new

mSerial = new FTDriver((UsbManager)getSystemService(Context.USB_SERVICE));

open

mSerial.begin(FTDriver.BAUD9600);

read n bytes

byte[] rbuf = new byte[n];
len = mSerial.read(rbuf);

read n bytes from channel p

byte[] rbuf = new byte[n];
len = mSerial.read(rbuf, n, p)

write n bytes

byte[] wbuf = new byte[n];
...(set wbuf)
len = mSerial.write(wbuf,n);

write n bytes to channel p

byte[] wbuf = new byte[n];
...(set wbuf)
len = mSerial.write(wbuf,n,p);

close

mSerial.end();