Swap CSS

rubyonrails-talk
1

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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2

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

Long

3

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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4

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

5

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

6

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:

   <link href="/stylesheets/main.css" rel="stylesheet" type="text/css" title="main" />    <link rel="alternate stylesheet" type="text/css" href="/stylesheets/print.css" title="print" />    <link rel="alternate stylesheet" type="text/css" href="/stylesheets/largetext.css" title="largetext" />    <script type="text/javascript" src="/javascripts/style_switch.js"></script>

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 setActiveStyleSheet(title) {    var i, a, main;    for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {      if(a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title")) {        a.disabled = true;        if(a.getAttribute("title") == title) a.disabled = false;      }    } }

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

7

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