i have OrangePi plus 2E i install Android OS and i try to gpio pin 13 on off but not working for me. i search google for gpio Android library didnt found. and i  see some video on youtube some one
do to gpio pin 13 work. my Android 4.2 is rooted i use terminal and get root access. the  code is ( echo 13 > /sys/class/gpio/export ) gpio pin connected LED 14 ground 13 is positive what i don its wrong or what is the problem ?  any one please HELP

UPDATE

pin 13 to 14 have 3v dc LED was on always can't off

First of all you have to have root to use GPIO under Android.
In Android terminal go root:

Then, you make handler for GPIO port manually:

Then you set GPIO mode on this pin to OUT (may be IN) by typping:

Then make this GPIO pin active by typping:

To make it inactive just type:


Hope this helps