Bootstrap - Plugin Scrollspy

O plugin Scroll Spy (atualização automática de navegação) permite que você direcione seções da página com base na posição de rolagem. Em sua implementação básica, conforme você rola, você pode adicionar.active classes para a barra de navegação com base na posição de rolagem.

Se você deseja incluir esta funcionalidade de plug-in individualmente, você precisará scrollspy.js. Além disso, conforme mencionado no capítulo Visão geral dos plug-ins de bootstrap , você pode incluir bootstrap.js ou bootstrap.min.js minimizado .

Uso

Você pode adicionar o comportamento de rolagem à sua navegação na barra superior -

  • Via data attributes - adicionar data-spy = "scroll"ao elemento que você deseja espionar (normalmente o corpo). Em seguida, adicione o atributodata-target com o ID ou classe do elemento pai de qualquer Bootstrap .navcomponente. Para que isso funcione, você deve ter elementos no corpo da página que tenham IDs correspondentes dos links que você está espionando.

<body data-spy = "scroll" data-target = ".navbar-example">
   ...
   <div class = "navbar-example">
      <ul class = "nav nav-tabs">
         ...
      </ul>
   </div>
   ...
</body>
  • Via JavaScript - Você pode invocar o scrollspy com JavaScript em vez de usar os atributos de dados, selecionando o elemento para espiar e invocando o .scrollspy() função -

$('body').scrollspy({ target: '.navbar-example' })

Exemplo

O exemplo a seguir mostra o uso do plugin scrollspy por meio de atributos de dados -

<nav id = "navbar-example" class = "navbar navbar-default navbar-static" role = "navigation">
   
   <div class = "navbar-header">
      <button class = "navbar-toggle" type = "button" data-toggle = "collapse" 
         data-target = ".bs-js-navbar-scrollspy">
         <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 = "#">Tutorial Name</a>
   </div>
   
   <div class = "collapse navbar-collapse bs-js-navbar-scrollspy">
      <ul class = "nav navbar-nav">
         <li><a href = "#ios">iOS</a></li>
         <li><a href = "#svn">SVN</a></li>
         
         <li class = "dropdown">
            <a href = "#" id = "navbarDrop1" class = "dropdown-toggle" data-toggle = "dropdown">
               Java
               <b class = "caret"></b>
            </a>
            
            <ul class = "dropdown-menu" role = "menu" aria-labelledby = "navbarDrop1">
               <li><a href = "#jmeter" tabindex = "-1">jmeter</a></li>
               <li><a href = "#ejb" tabindex = "-1">ejb</a></li>
               
               <li class = "divider"></li>
               <li><a href = "#spring" tabindex = "-1">spring</a></li>
            </ul>
            
         </li>
      </ul>
   </div>
   
</nav>

<div data-spy = "scroll" data-target = "#navbar-example" data-offset = "0" 
   style = "height:200px; overflow:auto; position: relative;">
   <h4 id = "ios">iOS</h4>
	
   <p>iOS is a mobile operating system developed and distributed by Apple 
      Inc. Originally released in 2007 for the iPhone, iPod Touch, and Apple 
      TV. iOS is derived from OS X, with which it shares the Darwin 
      foundation. iOS is Apple's mobile version of the OS X operating system 
      used on Apple computers.</p>
   
   <h4 id = "svn">SVN</h4>
   
   <p>Apache Subversion which is often abbreviated as SVN, is a software 
      versioning and revision control system distributed under an open source 
      license. Subversion was created by CollabNet Inc. in 2000, but now it 
      is developed as a project of the Apache Software Foundation, and as 
      such is part of a rich community of developers and users.</p>
   
   <h4 id = "jmeter">jMeter</h4>
   
   <p>jMeter is an Open Source testing software. It is 100% pure Java 
      application for load and performance testing.</p>
   
   <h4 id = "ejb">EJB</h4>
   
   <p>Enterprise Java Beans (EJB) is a development architecture for building 
      highly scalable and robust enterprise level applications to be deployed 
      on J2EE compliant Application Server such as JBOSS, Web Logic etc.</p>
   
   <h4 id = "spring">Spring</h4>
   
   <p>Spring framework is an open source Java platform that provides 
      comprehensive infrastructure support for developing robust Java 
      applications very easily and very rapidly.</p>
   
   <p>Spring framework was initially written by Rod Johnson and was first 
      released under the Apache 2.0 license in June 2003.</p>
   
</div>

Opções

As opções podem ser passadas por meio de atributos de dados ou JavaScript. A tabela a seguir lista as opções -

Nome da Opção Tipo / valor padrão Nome do atributo de dados Descrição
Deslocamento número Padrão: 10 deslocamento de dados Pixels para deslocar a partir do topo ao calcular a posição da rolagem.

Métodos

.scrollspy('refresh') - Ao chamar o scrollspy por meio do método JavaScript, você precisa chamar o .refreshmétodo para atualizar o DOM. Isso é útil se algum elemento do DOM foi alterado, ou seja, se você adicionou ou removeu alguns elementos. A seguir está a sintaxe para usar este método.

$('[data-spy = "scroll"]').each(function () {
   var $spy = $(this).scrollspy('refresh')
})

Exemplo

O exemplo a seguir demonstra o uso de .scrollspy('refresh') método -

<nav id = "myScrollspy" class = "navbar navbar-default navbar-static" role = "navigation">
   
   <div class = "navbar-header">
      <button class = "navbar-toggle" type = "button" data-toggle = "collapse" 
         data-target = ".bs-js-navbar-scrollspy">
         <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 = "#">Tutorial Name</a>
   </div>
   
   <div class = "collapse navbar-collapse bs-js-navbar-scrollspy">
      <ul class = "nav navbar-nav">
         <li class = "active"><a href = "#ios">iOS</a></li>
         <li><a href = "#svn">SVN</a></li>
         
         <li class = "dropdown">
            <a href = "#" id = "navbarDrop1" class = "dropdown-toggle" data-toggle  = "dropdown">
               Java 
               <b class = "caret"></b>
            </a>
            
            <ul class = "dropdown-menu" role = "menu" aria-labelledby = "navbarDrop1">
               <li><a href = "#jmeter" tabindex = "-1">jmeter</a></li>
               <li><a href = "#ejb" tabindex = "-1">ejb</a></li>
               
               <li class = "divider"></li>
               <li><a href = "#spring" tabindex = "-1">spring</a></li>
            </ul>
            
         </li>
      </ul>
   </div>
   
</nav>

<div data-spy = "scroll" data-target = "#myScrollspy" data-offset = "0"  
   style = "height:200px; overflow:auto; position: relative;">
   
   <div class = "section">
      <h4 id = "ios">iOS<small><a href = "#" onclick = "removeSection(this);">
         &times; Remove this section</a></small>
      </h4>
      
      <p>iOS is a mobile operating system developed and distributed by 
         Apple Inc. Originally released in 2007 for the iPhone, iPod Touch, and 
         Apple TV. iOS is derived from OS X, with which it shares the Darwin 
         foundation. iOS is Apple's mobile version of the OS X operating system
         used on Apple computers.</p>
   </div>
   
   <div class = "section">
      <h4 id = "svn">SVN<small></small></h4>
      <p>Apache Subversion which is often abbreviated as SVN, is a software 
         versioning and revision control system distributed under an open source 
         license. Subversion was created by CollabNet Inc. in 2000, but 
         now it is developed as a project of the Apache Software Foundation, 
         and as such is part of a rich community of developers and users.</p>
   </div>
   
   <div class = "section">
      <h4 id = "jmeter">jMeter<small><a href = "#" onclick = "removeSection(this);">
         &times; Remove this section</a></small>
      </h4>
      
      <p>jMeter is an Open Source testing software. It is 100% pure Java 
         application for load and performance testing.</p>
   </div>
   
   <div class = "section">
      <h4 id = "ejb">EJB</h4>
      
      <p>Enterprise Java Beans (EJB) is a development architecture for 
         building highly scalable and robust enterprise level applications 
         to be deployed on J2EE compliant Application Server such as 
         JBOSS, Web Logic etc.</p>
   </div>
	
   <div class = "section">
      <h4 id = "spring">Spring</h4>
      
      <p>Spring framework is an open source Java platform that provides 
         comprehensive infrastructure support for developing robust Java 
         applications very easily and very rapidly.</p>
      
      <p>Spring framework was initially written by Rod Johnson and was first 
         released under the Apache 2.0 license in June 2003.</p>
   </div>
   
</div>

<script type = "text/javascript">
   $(function(){
      removeSection = function(e) {
         $(e).parents(".section").remove();
         
         $('[data-spy = "scroll"]').each(function () {
            var $spy = $(this).scrollspy('refresh')
         });
      }
      $("#myScrollspy").scrollspy();
   });
</script>

Eventos

A tabela a seguir lista os eventos para trabalhar com scrollspy. Este evento pode ser usado para conectar-se à função.

Evento Descrição Exemplo
activate.bs.scrollspy Este evento é disparado sempre que um novo item é ativado pelo scrollspy.
$('#myScrollspy').on('activate.bs.scrollspy', function () {
   // do something…
})

Exemplo

O exemplo a seguir demonstra o uso de activate.bs.scrollspy evento -

<html>
   <head>
      <link rel = "stylesheet" href = "bootstrap/css/bootstrap.min.css">
      <script src = "bootstrap/scripts/jquery.min.js"></script>
      <script src = "bootstrap/js/bootstrap.min.js"></script>
      
      <script>
         $(document).ready(function(){
            removeSection = function(e) {
               $(e).parents(".subject").remove();
            
               $('[data-spy="scroll"]').each(function () {
                  var $spy = $(this).scrollspy('refresh')
               });
            }
         
            $("#Navexample").scrollspy();
         
            // The event is fired when an item gets actived with the scrollspy
            $("#Navexample").on('activate.bs.scrollspy', function () {
               var currentSection = $(".nav li.active > a").text();
               $("#spyevent").html("Current Item being viewed >> " + currentSection);
            })
				
         });
      </script>
   
      <style>
         .scroll-box {
            height: 250px;
            position: relative;
            overflow: auto;
            font-size:2em;
         }
      </style>
   </head>
   
   <body>
      <div class = "container">
         <nav id = "Navexample" class = "navbar navbar-default" role = "navigation">
      
            <!-- Nav Bar -->
            <div class = "navbar-header">
               <button type = "button" class = "navbar-toggle" 
                  data-toggle = "collapse" data-target = "#navbarCollapse">
               
                  <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 = "#">Tutorials Point</a>
            </div>
            
            <!-- Links and Sublinks -->
            <div class = "collapse navbar-collapse" id = "navbarCollapse">
               <ul class = "nav navbar-nav">
                  <li class = "active"><a href = "#subject-1">Subject 1</a></li>
                  <li><a href = "#subject-2">Subject 2</a></li>
               
                  <li class = "dropdown"><a href = "#" class = "dropdown-toggle" 
                     data-toggle = "dropdown">Subject 3<b class = "caret"></b></a>
                     
                     <ul class = "dropdown-menu">
                        <li><a href = "#subject-3-1">Subject 3.1</a></li>
                        <li><a href = "#subject-3-2">Subject 3.2</a></li>
                        <li><a href = "#subject-3-3">Subject 3.3</a></li>
                     </ul>
                     
                  </li>
						
                  <li><a href = "#subject-4">Subject 4</a></li>
               </ul>
            </div>
            
         </nav>
         
         <div class = "scroll-box" data-spy = "scroll" data-offset = "0">
            <div class = "subject">
            
               <h3 id = "subject-1">Subject 1 
                  <small><a href = "#" onclick = "removeSubject(this);">Remove Subject ×</a></small>
               </h3>
            
               <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit,
                  sed do eiusmod tempor incididunt ut labore et dolore magna
                  aliqua. Ut enim ad minim veniam, quis nostrud exercitation
                  ullamco laboris nisi ut aliquip ex ea commodo consequat.</p>
            </div>
				
            <hr>
         
            <div class = "subject">
               <h3 id = "subject-2">Subject 2 
                  <small><a href = "#" onclick = "removeSubject(this);">Remove Subject ×</a></small>
               </h3>
            
               <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit,
                  sed do eiusmod tempor incididunt ut labore et dolore magna
                  aliqua. Ut enim ad minim veniam, quis nostrud exercitation
                  ullamco laboris nisi ut aliquip ex ea commodo consequat.</p>
            </div>
				
            <hr>
         
            <div class = "subject">
               <h3 id = "subject-3">Subject 3 
                  <small><a href = "#" onclick = "removeSubject(this);"> Remove Subject ×</a></small>
               </h3>
            
               <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit,
                  sed do eiusmod tempor incididunt ut labore et dolore magna
                  aliqua. Ut enim ad minim veniam, quis nostrud exercitation
                  ullamco laboris nisi ut aliquip ex ea commodo consequat.</p><
            </div>
				
            <hr>
            
            <div class = "subject">
               <h4 id = "subject-3-1">Subject 3.1
                  <small><a href = "#" onclick = "removeSubject(this);"> Remove Subject ×</a></small>
               </h4>
               
               <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit,
                  sed do eiusmod tempor incididunt ut labore et dolore magna
                  aliqua. Ut enim ad minim veniam, quis nostrud exercitation
                  ullamco laboris nisi ut aliquip ex ea commodo consequat.</p>
            </div>
            
            <div class = "subject">
               <h4 id = "subject-3-2">Subject 3.2
                  <small><a href = "#" onclick = "removeSubject(this);"> Remove Subject ×</a></small>
               </h4>
               
               <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit,
                  sed do eiusmod tempor incididunt ut labore et dolore magna
                  aliqua. Ut enim ad minim veniam, quis nostrud exercitation
                  ullamco laboris nisi ut aliquip ex ea commodo consequat.</p>
            </div>
            
            <div class = "subject">
               <h4 id = "subject-3-3">Subject 3.3 
                  <small><a href = "#" onclick = "removeSubject(this);">Remove Subject ×</a></small>
               </h4>
               
               <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit,
                  sed do eiusmod tempor incididunt ut labore et dolore magna
                  aliqua. Ut enim ad minim veniam, quis nostrud exercitation
                  ullamco laboris nisi ut aliquip ex ea commodo consequat.</p>
            </div>
				
            <hr>
            
            <div class = "subject">
               <h3 id = "subject-4">Subject 4 
                  <small><a href = "#" onclick = "removeSubject(this);">Remove Subject ×</a></small>
               </h3>
               
               <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit,
                  sed do eiusmod tempor incididunt ut labore et dolore magna
                  aliqua. Ut enim ad minim veniam, quis nostrud exercitation
                  ullamco laboris nisi ut aliquip ex ea commodo consequat.</p>
            </div>
            
         </div>
         <hr>
         
         <h4 id = "spyevent" class = "text-info"></h4>
      </div>
   </body>
</html>