Can you believe there is still no undo(ctrl+z), redo(ctrl+y), find & replace(ctrl+f) when inputting on a touchscreen? Fortunately, Inputting+ can handle this.
https://play.google.com/store/apps/details?id=com.catchingnow.undo&hl=en
#undo
origin - http://www.pipiscrew.com/?p=6424 android-inputting-plus-ctrl-zfcv