mc^2: inject a "Toggle content" button to the Find File dialog.

find_file_toggle_content.lua

--[[

This snippet adds a "Toggle content" button to the Find File dialog. This
restores the old behavior of that dialog (which had a similar checkbox
before).

This was requested by a user in:

    http://www.midnight-commander.org/ticket/3680

]]

ui.Dialog.bind('<<open>>', function(dlg)

  if dlg.text == T'Find File' and dlg:find('Input') then  -- A crude way to detect the dialog.

    --
    -- Inject a "toggle" button to the dialog.
    --

    local btn = ui.Button(T'Toggle conte&nt')

    -- Put it to the right of the other buttons.
    btn.x = dlg.cols - btn.cols - 4
    btn.y = dlg.rows - 3

    btn.on_click = function()
      --
      -- Toggle the text in the content field.
      --

      local content = dlg:find('Input', 4)  -- The "Content:" field is the 4'th input field.

      if content.text == "" then
        -- Content is empty. Load the last history entry.
        content:command "HistoryPrev"
      else
        -- Clear content.
        content.text = ""
      end

      -- See queue()'s documentation for why we use it.
      ui.queue(function()
        content:focus()
        dlg:_send_message(ui.MSG_POST_KEY)  -- Update the checkboxes (enable/disable them appropriately).
        dlg:redraw_cursor()  -- After drawing the checkboxes, we put the cursor back at its correct place.
      end)

    end

    dlg:map_widget(btn:fixate())
    dlg:find('Input', 3):focus()  -- Move focus back to the "File name:" field.

  end

end)