Need help resizing android partition

[shogunreaper]

I have a chuwi hi8 pro and i don't use the windows side so i deleted the windows partitions to get more space following this tutorial - http://forum.chuwi.com/forum.php?mod=viewthread&tid=1880

but when i went to resize the android data partition it won't let me.

it goes

/dev/mmcblk09 android_data
/dev/mmcblk10 android_persistent
/dev/mmcblk11 android_config
/dev/mmcblk12 android_efi_system partition
unallocated 17.78gb

i'd post a screenshot but i cant figure out how to save one to usb while in gparted.

Does anyone know how to give the data partition the rest of the unallocated space?