滚动监听

根据滚动位置自动更新引导导航或列出组组件，以指示视口中当前处于活动状态的链接。

更新于: 2023-04-30 14:28:21 查看: 758

发布于: 2021-9-6 19:20 发布者: 大米

工作原理

有一些正常运行的要求：

它必须用于Bootstrap 导航组件 或 列表组上。
滚动监听需要设置 position: relative;；在要监视的元素上，通常是在 <body> 上设置。
锚点( <a> )是必需的，并且必须指向具有该 id 的元素。

当成功实现后，您的 nav 或 list 组将相应地更新，根据其关联的目标将 .active 从一个项目移动到下一个项目。

可滚动容器和键盘操作

如果要制作可滚动容器（而不是 <body> ），请确保设置了height 并将 overflow-y: scroll;；与 tabindex="0" 一起应用于该容器，以确保可以键盘操作。

导航栏中的示例

滚动导航栏下面的区域，观察处于活动类的变化。下拉项也将突出显示。

@fat

Ad leggings keytar, brunch id art party dolor labore. Pitchfork yr enim lo-fi before they sold out qui. Tumblr farm-to-table bicycle rights whatever. Anim keffiyeh carles cardigan. Velit seitan mcsweeney's photo booth 3 wolf moon irure. Cosby sweater lomo jean shorts, williamsburg hoodie minim qui you probably haven't heard of them et cardigan trust fund culpa biodiesel wes anderson aesthetic. Nihil tattooed accusamus, cred irony biodiesel keffiyeh artisan ullamco consequat.

@mdo

Veniam marfa mustache skateboard, adipisicing fugiat velit pitchfork beard. Freegan beard aliqua cupidatat mcsweeney's vero. Cupidatat four loko nisi, ea helvetica nulla carles. Tattooed cosby sweater food truck, mcsweeney's quis non freegan vinyl. Lo-fi wes anderson +1 sartorial. Carles non aesthetic exercitation quis gentrify. Brooklyn adipisicing craft beer vice keytar deserunt.

one

Occaecat commodo aliqua delectus. Fap craft beer deserunt skateboard ea. Lomo bicycle rights adipisicing banh mi, velit ea sunt next level locavore single-origin coffee in magna veniam. High life id vinyl, echo park consequat quis aliquip banh mi pitchfork. Vero VHS est adipisicing. Consectetur nisi DIY minim messenger bag. Cred ex in, sustainable delectus consectetur fanny pack iphone.

two

In incididunt echo park, officia deserunt mcsweeney's proident master cleanse thundercats sapiente veniam. Excepteur VHS elit, proident shoreditch +1 biodiesel laborum craft beer. Single-origin coffee wayfarers irure four loko, cupidatat terry richardson master cleanse. Assumenda you probably haven't heard of them art party fanny pack, tattooed nulla cardigan tempor ad. Proident wolf nesciunt sartorial keffiyeh eu banh mi sustainable. Elit wolf voluptate, lo-fi ea portland before they sold out four loko. Locavore enim nostrud mlkshk brooklyn nesciunt.

three

Keytar twee blog, culpa messenger bag marfa whatever delectus food truck. Sapiente synth id assumenda. Locavore sed helvetica cliche irony, thundercats you probably haven't heard of them consequat hoodie gluten-free lo-fi fap aliquip. Labore elit placeat before they sold out, terry richardson proident brunch nesciunt quis cosby sweater pariatur keffiyeh ut helvetica artisan. Cardigan craft beer seitan readymade velit. VHS chambray laboris tempor veniam. Anim mollit minim commodo ullamco thundercats.

<nav id="navbar-example2" class="navbar navbar-light bg-light px-3">
<a class="navbar-brand" href="#">Navbar</a>
<ul class="nav nav-pills">
<li class="nav-item">
  <a class="nav-link" href="#fat">@fat</a>
</li>
<li class="nav-item">
  <a class="nav-link" href="#mdo">@mdo</a>
</li>
<li class="nav-item dropdown">
  <a class="nav-link dropdown-toggle" data-bs-toggle="dropdown" href="#" role="button" aria-expanded="false">Dropdown</a>
  <ul class="dropdown-menu dropdown-menu-end">
    <li><a class="dropdown-item" href="#one">one</a></li>
    <li><a class="dropdown-item" href="#two">two</a></li>
    <li><hr class="dropdown-divider"></li>
    <li><a class="dropdown-item" href="#three">three</a></li>
  </ul>
</li>
</ul>
</nav>
<div data-bs-spy="scroll" data-bs-target="#navbar-example2" data-bs-offset="0" tabindex="0">
<h4 id="fat">@fat</h4>
<p>...</p>
<h4 id="mdo">@mdo</h4>
<p>...</p>
<h4 id="one">one</h4>
<p>...</p>
<h4 id="two">two</h4>
<p>...</p>
<h4 id="three">three</h4>
<p>...</p>
</div>

嵌套导航栏的示例

滚动监听也可以用于嵌套 .nav。如果嵌套的 .nav 是 .active，那么它的父对象也将是 .active。滚动导航栏旁边的区域，观察处于活动类的变化。

Item 1

Ex consequat commodo adipisicing exercitation aute excepteur occaecat ullamco duis aliqua id magna ullamco eu. Do aute ipsum ipsum ullamco cillum consectetur ut et aute consectetur labore. Fugiat laborum incididunt tempor eu consequat enim dolore proident. Qui laborum do non excepteur nulla magna eiusmod consectetur in. Aliqua et aliqua officia quis et incididunt voluptate non anim reprehenderit adipisicing dolore ut consequat deserunt mollit dolore. Aliquip nulla enim veniam non fugiat id cupidatat nulla elit cupidatat commodo velit ut eiusmod cupidatat elit dolore.

Item 1-1

Amet tempor mollit aliquip pariatur excepteur commodo do ea cillum commodo Lorem et occaecat elit qui et. Aliquip labore ex ex esse voluptate occaecat Lorem ullamco deserunt. Aliqua cillum excepteur irure consequat id quis ea. Sit proident ullamco aute magna pariatur nostrud labore. Reprehenderit aliqua commodo eiusmod aliquip est do duis amet proident magna consectetur consequat eu commodo fugiat non quis. Enim aliquip exercitation ullamco adipisicing voluptate excepteur minim exercitation minim minim commodo adipisicing exercitation officia nisi adipisicing. Anim id duis qui consequat labore adipisicing sint dolor elit cillum anim et fugiat.

Item 1-2

Cillum nisi deserunt magna eiusmod qui eiusmod velit voluptate pariatur laborum sunt enim. Irure laboris mollit consequat incididunt sint et culpa culpa incididunt adipisicing magna magna occaecat. Nulla ipsum cillum eiusmod sint elit excepteur ea labore enim consectetur in labore anim. Proident ullamco ipsum esse elit ut Lorem eiusmod dolor et eiusmod. Anim occaecat nulla in non consequat eiusmod velit incididunt.

Item 2

Quis magna Lorem anim amet ipsum do mollit sit cillum voluptate ex nulla tempor. Laborum consequat non elit enim exercitation cillum aliqua consequat id aliqua. Esse ex consectetur mollit voluptate est in duis laboris ad sit ipsum anim Lorem. Incididunt veniam velit elit elit veniam Lorem aliqua quis ullamco deserunt sit enim elit aliqua esse irure. Laborum nisi sit est tempor laborum mollit labore officia laborum excepteur commodo non commodo dolor excepteur commodo. Ipsum fugiat ex est consectetur ipsum commodo tempor sunt in proident.

Item 3

Quis anim sit do amet fugiat dolor velit sit ea ea do reprehenderit culpa duis. Nostrud aliqua ipsum fugiat minim proident occaecat excepteur aliquip culpa aute tempor reprehenderit. Deserunt tempor mollit elit ex pariatur dolore velit fugiat mollit culpa irure ullamco est ex ullamco excepteur.

Item 3-1

Deserunt quis elit Lorem eiusmod amet enim enim amet minim Lorem proident nostrud. Ea id dolore anim exercitation aute fugiat labore voluptate cillum do laboris labore. Ex velit exercitation nisi enim labore reprehenderit labore nostrud ut ut. Esse officia sunt duis aliquip ullamco tempor eiusmod deserunt irure nostrud irure. Ullamco proident veniam laboris ea consectetur magna sunt ex exercitation aliquip minim enim culpa occaecat exercitation. Est tempor excepteur aliquip laborum consequat do deserunt laborum esse eiusmod irure proident ipsum esse qui.

Item 3-2

Labore sit culpa commodo elit adipisicing sit aliquip elit proident voluptate minim mollit nostrud aute reprehenderit do. Mollit excepteur eu Lorem ipsum anim commodo sint labore Lorem in exercitation velit incididunt. Occaecat consectetur nisi in occaecat proident minim enim sunt reprehenderit exercitation cupidatat et do officia. Aliquip consequat ad labore labore mollit ut amet. Sit pariatur tempor proident in veniam culpa aliqua excepteur elit magna fugiat eiusmod amet officia.

<nav id="navbar-example3" class="navbar navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar</a>
<nav class="nav nav-pills flex-column">
<a class="nav-link" href="#item-1">Item 1</a>
<nav class="nav nav-pills flex-column">
  <a class="nav-link ms-3 my-1" href="#item-1-1">Item 1-1</a>
  <a class="nav-link ms-3 my-1" href="#item-1-2">Item 1-2</a>
</nav>
<a class="nav-link" href="#item-2">Item 2</a>
<a class="nav-link" href="#item-3">Item 3</a>
<nav class="nav nav-pills flex-column">
  <a class="nav-link ms-3 my-1" href="#item-3-1">Item 3-1</a>
  <a class="nav-link ms-3 my-1" href="#item-3-2">Item 3-2</a>
</nav>
</nav>
</nav>

<div data-bs-spy="scroll" data-bs-target="#navbar-example3" data-bs-offset="0" tabindex="0">
<h4 id="item-1">Item 1</h4>
<p>...</p>
<h5 id="item-1-1">Item 1-1</h5>
<p>...</p>
<h5 id="item-1-2">Item 1-2</h5>
<p>...</p>
<h4 id="item-2">Item 2</h4>
<p>...</p>
<h4 id="item-3">Item 3</h4>
<p>...</p>
<h5 id="item-3-1">Item 3-1</h5>
<p>...</p>
<h5 id="item-3-2">Item 3-2</h5>
<p>...</p>
</div>

列表组合示例

滚动监听还可以用于 .list-group。滚动列表组旁边的区域并观察处于活动类的变化。

Item 1 Item 2 Item 3 Item 4

Item 1

This is some placeholder content for the scrollspy page. Note that as you scroll down the page, the appropriate navigation link is highlighted. It's repeated throughout the component example. We keep adding some more example copy here to emphasize the scrolling and highlighting.

Item 2

Item 3

Item 4

<div id="list-example" class="list-group">
  <a class="list-group-item list-group-item-action" href="#list-item-1">Item 1</a>
  <a class="list-group-item list-group-item-action" href="#list-item-2">Item 2</a>
  <a class="list-group-item list-group-item-action" href="#list-item-3">Item 3</a>
  <a class="list-group-item list-group-item-action" href="#list-item-4">Item 4</a>
</div>
<div data-bs-spy="scroll" data-bs-target="#list-example" data-bs-offset="0" class="scrollspy-example" tabindex="0">
  <h4 id="list-item-1">Item 1</h4>
  <p>...</p>
  <h4 id="list-item-2">Item 2</h4>
  <p>...</p>
  <h4 id="list-item-3">Item 3</h4>
  <p>...</p>
  <h4 id="list-item-4">Item 4</h4>
  <p>...</p>
</div>

用法

通过数据属性

要简便地将滚动监听的行为添加到您的顶部导航栏中，请将 data-bs-spy="scroll" 添加到您要监听的元素（一般情况下是添加到 <body> 上）。然后添加带有任何Bootstrap .nav 组件的父元素的ID或class的 data-bs-target 属性。

body {
position: relative;
}

<body data-bs-spy="scroll" data-bs-target="#navbar-example">
...
<div id="navbar-example">
<ul class="nav nav-tabs" role="tablist">
  ...
</ul>
</div>
...
</body>

通过JavaScript

在CSS中添加 position: relative; 之后，通过JavaScript调用Scrollspy：

var scrollSpy = new bootstrap.ScrollSpy(document.body, {
  target: '#navbar-example'
})

需要可解析的目标ID

导航栏链接必须要有可解析的id目标。例如，<a href="#home">home</a> 必须对应于DOM中的某些内容，如<div id="home"></div>。

忽略不可见的目标元素

不可见的目标元素将被忽略，它们对应的导航栏项也不会突出显示。

方法

提示

在使用scrollspy并从DOM中添加或删除元素时，您需要像这样调用refresh方法：

var dataSpyList = [].slice.call(document.querySelectorAll('[data-bs-spy="scroll"]'))
dataSpyList.forEach(function (dataSpyEl) {
  bootstrap.ScrollSpy.getInstance(dataSpyEl)
    .refresh()
})

处理

销毁元素中的scrollspy。（删除存储在DOM元素上的数据）

获取实例

静态方法，该方法允许您获取与DOM元素关联的scrollspy实例

var scrollSpyContentEl = document.getElementById('content')
var scrollSpy = bootstrap.ScrollSpy.getInstance(scrollSpyContentEl) // Returns a Bootstrap scrollspy instance

获取创建实例

静态方法，该方法允许您获取与DOM元素关联的scrollspy实例，或者创建一个新的实例，以防它没有进行初始化

var scrollSpyContentEl = document.getElementById('content')
var scrollSpy = bootstrap.ScrollSpy.getOrCreateInstance(scrollSpyContentEl) // Returns a Bootstrap scrollspy instance

选项

选项可以通过数据属性或JavaScript传递。对于数据属性，将选项名称追加到 data-bs-，如 data-bs-offset=""。

名称	类型	默认	描述
`offset`	number	`10`	计算滚动位置时，从顶部开始偏移的像素。
`method`	string	`auto`	找到被监视元素所在的区域。 `auto` 将选择获得滚动坐标的最佳方法。偏移量将使用 `Element.getBoundingClientRect()` 获取滚动坐标的方法。位置将使用`HTMLElement.offsetTop`以及`HTMLElement.offsetLeft`属性以获取滚动坐标。
`target`	string \| jQuery object \| DOM element		指定要使用Scrollspy插件的元素。

方法

事件类型	描述
`activate.bs.scrollspy`	每当scrollspy激活一个新项目时，此事件就在scroll元素上激发。

var firstScrollSpyEl = document.querySelector('[data-bs-spy="scroll"]')
firstScrollSpyEl.addEventListener('activate.bs.scrollspy', function () {
// do something...
})

Bootstrap

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