How to adjust dired-omit-mode

Question

Goal:

• When dired is opened by default hidden files should be hidden.
• When the user clicks "M-q" hidden files must be shown except for "." and ".."

I tried the following:

;don't show hidden files
(setq dired-omit-files "^\\..*$")
(defun swap-omit-files ()
      "Show/hide hidden files except . and .."
      (interactive)
      (if (string= dired-omit-files "^\\..*$")
            (setq dired-omit-files "^\\.\\.?$")
            (setq dired-omit-files "^\\..*$")
            )
      )

(add-hook 'dired-mode-hook
      (lambda ()
            (setq dired-omit-mode t)
            (define-key dired-mode-map (kbd "M-q") 'swap-omit-files)
            ))

Hidden file are indeed hidden by default, but something is wrong with swap-omit-files --- the hidden files are not shown.

How to fix?

Answer 1

This worked. We needed to revert-buffer after changing dired-omit-files:

(defun swap-omit-files ()
      "Show/hide hidden files except . and .."
      (interactive)
      (if (string= dired-omit-files "^\\..*$")
            (setq dired-omit-files "^\\.\\.?$")
            (setq dired-omit-files "^\\..*$")
            )
      (revert-buffer)
      )