Swap CSS

Pete_Wright · March 13, 2020, 10:18pm

Presumably, the easiest way to do this would be to have some session value, or an instance variable, hold the stylesheet choice and reference that in the layout…

<%= stylesheet_link_tag “#{session[:stylesheet]}” %>

Your button, when clicked, would simply update this session value.

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Long · March 13, 2020, 11:57pm

Perhaps #{params[:style]} may work better as you can link to it quite
easily.

Long

Pete_Wright · March 13, 2020, 11:57pm

But if we’re talking about a stylesheet applied to a layout used in all pages of the app, wouldn’t params make things a little tricky?

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JDL · March 13, 2020, 11:57pm

You could set it in a cookie too, so that the user gets his choice of
styles back automatically.

Stephen_Bartholomew2 · March 13, 2020, 11:57pm

But if we're talking about a stylesheet applied to a layout used in all pages of the app, wouldn't params make things a little tricky?

It'd make it very tricky.

I'd say have a StylesController with a 'switch' method

class StylesController < ApplicationController
   def switch
     if params[:style]
       session[:stylesheet] = params[:style]
     end
   end
end

Then a nice route:

map.connect '/style/switch/:style/'

to make urls like this:

/style/switch/print
or
/style/switch/large_text

Then in the layout:

<%= stylesheet_link_tag session[:stylesheet] || "my_default" %>

As long as you name your stylesheets print.css or large_text.css they'll be picked up. If nothing is specified, your default stylesheet will be loaded.

Hope that helps,

Steve

Ezra_Zygmuntowicz · March 13, 2020, 11:57pm

The nice way to do this IMHO is to use alternate style sheet tags and a little js to set a cookie. That way you can switch the stylesheet without reloading the page. Something like this:

In the head of your layout:

The links to change the stylesheet:

<a href="#" onclick="setActiveStyleSheet('main');return false;">Main</a>
<a href="#" onclick="setActiveStyleSheet('print');return false;">Print</a>
<a href="#" onclick="setActiveStyleSheet('largetext');return false;">Large Text</a>

And the style_switch.js file:

function getActiveStyleSheet() {
   var i, a;
   for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
     if(a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title") && !a.disabled) return a.getAttribute("title");
   }
   return null;
}

function getPreferredStyleSheet() {
   var i, a;
   for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
     if(a.getAttribute("rel").indexOf("style") != -1
        && a.getAttribute("rel").indexOf("alt") == -1
        && a.getAttribute("title")
        ) return a.getAttribute("title");
   }
   return null;
}

function createCookie(name,value,days) {
   if (days) {
     var date = new Date();
     date.setTime(date.getTime()+(days*24*60*60*1000));
     var expires = "; expires="+date.toGMTString();
   }
   else expires = "";
   document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
   var nameEQ = name + "=";
   var ca = document.cookie.split(';');
   for(var i=0;i < ca.length;i++) {
     var c = ca[i];
     while (c.charAt(0)==' ') c = c.substring(1,c.length);
     if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
   }
   return null;
}

window.onload = function(e) {
   var cookie = readCookie("style");
   var title = cookie ? cookie : getPreferredStyleSheet();
   setActiveStyleSheet(title);
}

window.onunload = function(e) {
var title = getActiveStyleSheet();
createCookie("style", title, 365);
}

var cookie = readCookie("style");
var title = cookie ? cookie : getPreferredStyleSheet();
setActiveStyleSheet(title);

Cheers-
-Ezra

Long · March 13, 2020, 11:57pm

Hmm, you are right. I got a bit ahead of myself there.

The approach I would take is to add a before_filter. It would
check params for a "new" style and set the value in the session,
like you've suggested.

Now one can construct links to switch styles with ease.

Long