DroidVim is a Vim clone text editor ported for Android.
Vim 8 (huge version multi language) grep diff and ctags are ready to use.

â–¼ Required - ARM (Android 4.1 and up) x86 (Android 4.3 and up)
Features:

â–¼ External storage support - External SD card USB memory GoogleDrive Dropbox etc. (Requires Android 4.4 and up)
â–¼ Special Keys - Esc Ctrl Tab Arrow keys and more.
â–¼ Direct input - Disabling predictive text and/or auto correction for normal mode.
â–¼ Clipboard - Clipboard commands ("*p "*y) are supported.
â–¼ Custom Font - Use your favorite monospaced font.
â–¼ Touch to move - Touch swipe flick to move cursor.
â–¼ Multi language - Vim with multi byte option iconv and multi language messages.

Extra features (in-app purchase):
â–¼Git - Version Control System.
â–¼Python - Programming language.

Appendix:
DroidVim is an open source project.