如何使用 React js 添加平滑滚动返回顶部按钮？

Question

我已经使用 jquery 实现了这个，但想创建一个组件来响应做同样的事情

<script>            
jQuery(document).ready(function() {
    var offset = 220;
    var duration = 500;
    jQuery(window).scroll(function() {
        if (jQuery(this).scrollTop() > offset) {
            jQuery('.move-top').fadeIn(duration);
        } else {
            jQuery('.move-top').fadeOut(duration);
        }
    });

    jQuery('.move-top').click(function(event) {
        event.preventDefault();
        jQuery('html, body').animate({scrollTop: 0}, duration);
        return false;
    })
});
</script>

在我的页脚中

<a href="#" class="move-top">↑</a>

Answer 1

首先，我们需要跟踪页面在组件状态下的滚动情况。这种跟踪应该只在组件安装时发生。可以这样做：

getInitialState: function() {
  return { scrollTop: 0 };
},
componentWillMount: function() {
  window.addEventListener('scroll', this.handleScroll);
},
componentWillUnmount: function() {
  window.removeEventListener('scroll', this.handleScroll);
},
handleScroll: function() {
   this.setState({scrollTop: $(window).scrollTop()});
},

注意：这仍然是使用 jQuery 来获取当前滚动位置。请参阅 this question 以在不使用 jQuery 的情况下执行此操作。

然后我们需要渲染组件：

scrollToTop: function() {
  $(window).animate({scrollTop: 0}, this.props.duration);
},
render: function() {
  if (this.state.scrollTop < this.props.offset) {
    return null;
  }

  return <a href="#" className="move-top" onClick={this.scrollToTop}>↑</a>
}

这仍然使用 jQuery 来进行实际的滚动。看看this question 没有 jQuery 的滚动。

如果你想让这个组件淡入淡出，你应该用ReactCSSTransitionGroup 包裹它并使用CSS 动画。这记录在React docs。

这是一个JSFiddle 演示。

Answer 2

在 google 上搜索后，我在 JSFiddle 中找到了您需要的 jQuery 代码。然后，我重新排序了你的 jQuery：

$(document).ready(function() {

  $(window).scroll(function() {
    if ($(this).scrollTop() > 100) {
      $('.move-top').fadeIn();
    } else {
      $('.move-top').fadeOut();
    }
  });

  $('.move-top').click(function() {
    $("html, body").animate({
      scrollTop: 0
    }, 600);
    return false;
  });

});

.container {
  min-height: 1000px;
}

.move-top {
  position: fixed;
  bottom: 50px;
  right: 100px;
  display: none;
  padding: 10px 15px;
  color: #fff;
  font-weight: 600;
  background: #333;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.2/jquery.min.js"></script>
<h1>Page Header</h1>
<div class="container">
  <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. Duis aute irure dolor
    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
  </p>
  <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. Duis aute irure dolor
    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
  </p>
  <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. Duis aute irure dolor
    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
  </p>
  <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. Duis aute irure dolor
    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
  </p>
  <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. Duis aute irure dolor
    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
  </p>
  <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. Duis aute irure dolor
    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
  </p>
  <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. Duis aute irure dolor
    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
  </p>

  <a class="move-top" href="#">↑</a>
</div>
<h3>Page Footer</h3>

Answer 3

如果你想完全避免使用 jQuery

var Example = React.createClass({
    scrollUp: function () {
        var doc = document.documentElement;
        var top = (window.pageYOffset || doc.scrollTop) - (doc.clientTop || 0);

        if (top > 0) {
            window.scrollTo(0, top - 15)
            setTimeout(this.scrollUp, 10)
        }
    },
    render: function () {
        return (<div><h1>Page Header</h1>
            <div ref="container" className="container">
                <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. Duis aute irure dolor
                    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint
                    occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
                </p>
                <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. Duis aute irure dolor
                    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint
                    occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
                </p>
                <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. Duis aute irure dolor
                    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint
                    occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
                </p>
                <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. Duis aute irure dolor
                    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint
                    occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
                </p>
                <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. Duis aute irure dolor
                    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint
                    occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
                </p>
                <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. Duis aute irure dolor
                    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint
                    occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
                </p>
                <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. Duis aute irure dolor
                    in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint
                    occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
                </p>

                <a className="move-top" onClick={this.scrollUp}>Up</a>
            </div>
        </div>);
    }
});

Answer 4

像这样使用下面的代码：

smoothScroll.scrollTo(ID_OF_DOM_ELEMENT, OPTIONAL_CALLBACK_ON_SCROLL_DONE)

代码：

var smoothScroll = {

    timer: null,

    stop: function () {
        clearTimeout(this.timer);
    },

    scrollTo: function (id, callback) {
        var settings = {
            duration: 1000,
            easing: {
                outQuint: function (x, t, b, c, d) {
                    return c*((t=t/d-1)*t*t*t*t + 1) + b;
                }
            }
        };
        var percentage;
        var startTime;
        var node = document.getElementById(id);
        var nodeTop = node.offsetTop;
        var nodeHeight = node.offsetHeight;
        var body = document.body;
        var html = document.documentElement;
        var height = Math.max(
            body.scrollHeight,
            body.offsetHeight,
            html.clientHeight,
            html.scrollHeight,
            html.offsetHeight
        );
        var windowHeight = window.innerHeight
        var offset = window.pageYOffset;
        var delta = nodeTop - offset;
        var bottomScrollableY = height - windowHeight;
        var targetY = (bottomScrollableY < delta) ?
            bottomScrollableY - (height - nodeTop - nodeHeight + offset):
            delta;

        startTime = Date.now();
        percentage = 0;

        if (this.timer) {
            clearInterval(this.timer);
        }

        function step () {
            var yScroll;
            var elapsed = Date.now() - startTime;

            if (elapsed > settings.duration) {
                clearTimeout(this.timer);
            }

            percentage = elapsed / settings.duration;

            if (percentage > 1) {
                clearTimeout(this.timer);

                if (callback) {
                    callback();
                }
            } else {
                yScroll = settings.easing.outQuint(0, elapsed, offset, targetY, settings.duration);
                window.scrollTo(0, yScroll);
                this.timer = setTimeout(step, 10);
            }
        }

        this.timer = setTimeout(step, 10);
    }
};

Answer 5

我认为react-scroll 值得一提，将其添加到组件的click 处理程序（onClick={this.handleClick}）

import Scroll from 'react-scroll'

...
Scroll.animateScroll.scrollToTop({options})
...

选项是根据Props/Options指定的对象

Answer 6

我不建议混合使用 jQuery 和 React/Angular。使用 'react-scroll' 可以轻松完成，如下所示：

import React, { Component } from 'react';
import ReactDOM from 'react-dom';
import { animateScroll as scroll } from 'react-scroll';

class Scrolltotop extends Component {

    ScrollTo() {
        scroll.scrollToTop();
    }

    render() {

        return (
            <div className="move-top-wrap">                 
                <div onClick={this.ScrollTo} class="move-top">↑</div> 
            </div>
        );

    }

}
export default Scrolltotop;

您可以查看所有basic examples of react-scroll usage here。

您现在可以在任何地方导入和使用该组件。