nds4droid by jeffq is a free, open source Nintendo DS emulator written for Android smartphones. It is based off of the excellent emulator DeSmuME. The source code can be found on sourceforge.
Changes:
-Adds a new German translation (thanks Nathaniel D.)
-Converted project to Android Studio and moved to GitHub. The source now lives at https://github.com/jquesnelle/nds4droid
https://play.google.com/store/apps/details?id=com.opendoorstudios.ds4droid