This keyboard was developed Under the USAID funded SPICE program to support every version of android smart phone. This means that typing in Cham language have never been a barrier for those who loved to use their local language to share and improve their conversations through communication channel. You could find all Cham glyphs on the keyboard which was prepared according to the common usage of the script. Although, you still need to install Cham font to display input text.
For Samsung smart phone you could install font(No need to root phone) by downloading Cham_Font_Samsung.apk application from http://www.open.org.kh/km/node/570#attachments . And go to setting -> display -> fontstyle -> select Cham.
Anyway, It is licensed under a LGPL license that allows free use, copying and distribution.