What's the reason behind bootstrap's grid system not working properly in a rails project?

Question

I followed the instructions written here - https://github.com/twbs/bootstrap-sass But bootstrap seems to be not working. I installed the gems needed, updated files written in the github documentation, and then in my application_layout,

<nav class="navbar navbar-inverse navbar-fixed-top">
  <div class="container">
    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="#">Project name</a>
    </div>
    <div id="navbar" class="navbar-collapse collapse">
      <form class="navbar-form navbar-right">
        <div class="form-group">
          <input type="text" placeholder="Email" class="form-control">
        </div>
        <div class="form-group">
          <input type="password" placeholder="Password" class="form-control">
        </div>
        <button type="submit" class="btn btn-success">Sign in</button>
      </form>
    </div><!--/.navbar-collapse -->
  </div>
</nav>

<!-- Main jumbotron for a primary marketing message or call to action -->
<div class="jumbotron">
  <div class="container">
    <h1>Hello, world!</h1>
    <p>This is a template for a simple marketing or informational website. It includes a large callout called a jumbotron and three supporting pieces of content. Use it as a starting point to create something more unique.</p>
    <p><a class="btn btn-primary btn-lg" href="#" role="button">Learn more &raquo;</a></p>
  </div>
</div>

<div class="container">
  <!-- Example row of columns -->
  <div class="row">
    <div class="col-md-4">
      <h2>Heading</h2>
      <p>Donec id elit non mi porta gravida at eget metus. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui. </p>
      <p><a class="btn btn-default" href="#" role="button">View details &raquo;</a></p>
    </div>
    <div class="col-md-4">
      <h2>Heading</h2>
      <p>Donec id elit non mi porta gravida at eget metus. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui. </p>
      <p><a class="btn btn-default" href="#" role="button">View details &raquo;</a></p>
   </div>
    <div class="col-md-4">
      <h2>Heading</h2>
      <p>Donec sed odio dui. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Vestibulum id ligula porta felis euismod semper. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus.</p>
      <p><a class="btn btn-default" href="#" role="button">View details &raquo;</a></p>
    </div>
  </div>

  <hr>

  <footer>
    <p>&copy; Company 2014</p>
</footer>

it breaks the layout and the grids comes one under another.

Answer 1

I think the reason your bootstrap grid is not working in your browser is that your screen resolution might be too small. Since its small it requires the col-sm-4 class and you also forget a to close out the container. I've posted a fiddle https://jsfiddle.net/rvega20/pogfb4w9/

Also as mentioned before in order to use bootstrap-sass, one has to use the main syntax (as of Sass 3) which is known as "SCSS". So straight from the bootstrap documentation --> Make sure the file has .scss extension (or .sass for Sass syntax). If you have just generated a new Rails app, it may come with a .css file instead. If this file exists, it will be served instead of Sass, so rename it:

$ mv app/assets/stylesheets/application.css app/assets/stylesheets/application.scss

Then, remove all the //= require and //= require_tree statements from the file. Instead, use @import to import Sass files.

Do not use //= require in Sass or your other stylesheets will not be able to access the Bootstrap mixins or variables.

Require Bootstrap Javascripts in app/assets/javascripts/application.js:

//= require jquery
//= require bootstrap-sprockets

bootstrap-sprockets and bootstrap should not both be included in application.js.

bootstrap-sprockets provides individual Bootstrap Javascript files (alert.js or dropdown.js, for example), while bootstrap provides a concatenated file containing all Bootstrap Javascripts.

   <nav class="navbar navbar-inverse navbar-fixed-top">
  <div class="container">
    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="#">Project name</a>
    </div>
    <div id="navbar" class="navbar-collapse collapse">
      <form class="navbar-form navbar-right">
        <div class="form-group">
          <input type="text" placeholder="Email" class="form-control">
        </div>
        <div class="form-group">
          <input type="password" placeholder="Password" class="form-control">
        </div>
        <button type="submit" class="btn btn-success">Sign in</button>
      </form>
    </div><!--/.navbar-collapse -->
  </div>
</nav>

<!-- Main jumbotron for a primary marketing message or call to action -->
<div class="jumbotron">
  <div class="container">
    <h1>Hello, world!</h1>
    <p>This is a template for a simple marketing or informational website. It includes a large callout called a jumbotron and three supporting pieces of content. Use it as a starting point to create something more unique.</p>
    <p><a class="btn btn-primary btn-lg" href="#" role="button">Learn more &raquo;</a></p>
  </div>
</div>

<div class="container">
  <!-- Example row of columns -->
  <div class="row">
    <div class="col-md-4 col-sm-4">
      <h2>Heading</h2>
      <p>Donec id elit non mi porta gravida at eget metus. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui. </p>
      <p><a class="btn btn-default" href="#" role="button">View details &raquo;</a></p>
    </div>
    <div class="col-md-4 col-sm-4">
      <h2>Heading</h2>
      <p>Donec id elit non mi porta gravida at eget metus. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui. </p>
      <p><a class="btn btn-default" href="#" role="button">View details &raquo;</a></p>
   </div>
    <div class="col-md-4 col-sm-4">
      <h2>Heading</h2>
      <p>Donec sed odio dui. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Vestibulum id ligula porta felis euismod semper. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus.</p>
      <p><a class="btn btn-default" href="#" role="button">View details &raquo;</a></p>
    </div>
  </div>
      </div>
  <hr>

  <footer>
    <p>&copy; Company 2014</p>
</footer>

Answer 2

Check your application.css file - it must be removed, and instead of it you must have application.css.scss file with contents:

@import "bootstrap-sprockets"; @import "bootstrap";

Answer 3

I'll try to guess what your problem is, but you haven't provided the necessary context code so it's impossible for anyone to answer you with any certainty.

I'm guessing you don't have that nested inside a row div.