vim: Nerdtree Integration

.vimrc

@@ -6,6 +6,8 @@ set rtp+=~/.vim/bundle/Vundle.vim
 call vundle#begin('~/.vim/plugged')
 " Let Vundle manage Vundle; muss immer der erste Eintrag sein
 Plugin 'VundleVim/Vundle.vim'
+" project drawer
+Plugin 'preservim/nerdtree'
 " ansible integration
 Plugin 'pearofducks/ansible-vim'
 " omnicompletion während dem tippen
@@ -187,6 +189,8 @@ nmap Y y$
 " https://www.reddit.com/r/vim/comments/s1he17/is_there_a_plugin_that_makes_searching_and
 nnoremap <Leader>sr  :%s/<C-r><C-w>//gc<Left><Left><Left>
 vnoremap <Leader>sr  y:%s/<C-R>"//gc<Left><Left><Left>
+" Toggle NERDTree
+nnoremap <F2> :NERDTreeToggle<CR>
 
 " ### Abbreviations
 iabbrev ncicht nicht
@@ -203,3 +207,11 @@ nnoremap <Leader>z :set nonumber! norelativenumber!<CR>
 
 " entferne trailing whitespaces beim speichern
 autocmd BufWritePre * :%s/\s\+$//e
+
+" Start NERDTree when Vim is started without file arguments.
+autocmd StdinReadPre * let s:std_in=1
+autocmd VimEnter * if argc() == 0 && !exists('s:std_in') | NERDTree | endif
+" Exit Vim if NERDTree is the only window remaining in the only tab.
+autocmd BufEnter * if tabpagenr('$') == 1 && winnr('$') == 1 && exists('b:NERDTree') && b:NERDTree.isTabTree() | quit | endif
+" NERDTree - show hidden files
+let NERDTreeShowHidden=1