Xender is a cross-platform file sharing app that allows you to share files across various platforms and devices. 

It has proved to be very useful to share apps created by the SIL App Builders (SAB, DAB, RAB) or Bloom without the need for a USB cable, computer, additonal software or an internet connection. 

https://play.google.com/store/apps/details?id=cn.xender&hl=en_US