How to configure theme editor and default encoding in .Rprofile

Question

I want to configure my .Rprofile in order to :

• Apply the editor theme in RStudio to "Idle fingers"
• Set default encoding for source files to "UTF-8"

I don't want to use RStudio menus to do this

What I tried :

library(rstudioapi)
rstudioapi::applyTheme("Idle Fingers")

I got this message Error : RStudio not running

Many thanks in advance !