Seamlessly change focus between i3 windows and Vim splits using the same hotkey.
This depends on you having a couple packages installed. Most notably, xdotool/libxdo, the second of which should be installed as a dependency of the first. If you want to build the binary from source and you're on Fedora, you'll also need the libxdo-devel package. We also currently require you to be using a version of vim with either python or python3 support.
First, install the Vim plugin.
In your .vimrc (vim) or .config/nvim/init.vim (neovim):
Plug 'termhn/i3-vim-nav'
" i3 integration
nmap <silent> <C-M-l> <C-l>
nmap <silent> <C-M-h> <C-h>
nmap <silent> <C-M-k> <C-k>
nmap <silent> <C-M-j> <C-j>
nnoremap <silent> <C-l> :call Focus('right', 'l')<CR>
nnoremap <silent> <C-h> :call Focus('left', 'h')<CR>
nnoremap <silent> <C-k> :call Focus('up', 'k')<CR>
nnoremap <silent> <C-j> :call Focus('down', 'j')<CR>Assuming that i3 $mod is set to the alt key.
Next, install the binary on your PATH. If you have go installed, this can be done simply by
go get -u github.com/termhn/i3-vim-nav
If not, you can symlink the binary from its downloaded directory (this changes based on which plugin manager you used and if you're using vim or neovim) into /usr/local/bin. For example, if you used Pathogen on default Vim, this would be:
ln -s ~/.vim/bundle/i3-vim-nav/i3-vim-nav /usr/local/bin
Then, in your i3 config (adjust the path to the executable as necessary if you installed it differently). Feel free to change the key bind as you please.
bindsym --release $mod+h exec --no-startup-id "i3-vim-nav h"
bindsym --release $mod+j exec --no-startup-id "i3-vim-nav j"
bindsym --release $mod+k exec --no-startup-id "i3-vim-nav k"
bindsym --release $mod+l exec --no-startup-id "i3-vim-nav l"
Note: I've gotten a bug where in some installations of i3, it seems to not respect user $PATH additions, even though it seems to recognize them in the variable. If it doesn't work when placed in a user $PATH directory, try hard-coding the path to the binary in the exec commands.