Question

我正在锻炼，我试图在纯JS上写自己的旋转木马。

window.onload = function () {

    var slider = document.getElementById('slide-list');
    var left = document.getElementById('rewind');
    var right = document.getElementById('forward');

    var clickDisabled = false;

    function spin() {
        slider.firstChild.style.marginLeft = -800 + 'px';
        setTimeout(function () {
            slider.appendChild(slider.removeChild(slider.firstChild));
            slider.lastChild.style.marginLeft = '0px';
        }, 2000);
    }

    var slideShow = setInterval(spin, 4000);

    left.onclick = function () {
        if (clickDisabled) {return;}
        else {
            clickDisabled = true;
            clearInterval(slideShow);
            slider.lastChild.style.marginLeft = -800 + 'px';
            slider.insertBefore(slider.lastChild, slider.firstChild);
            // the crutch - try to unwrap content from timeout and see that image changes instantly, with no transition
            setTimeout(function () { slider.firstChild.style.marginLeft = '0px'; }, 1);
            slideShow = setInterval(spin, 4000);
            setTimeout(function() {clickDisabled = false;}, 2000);
        }
    }

    right.onclick = function () {
        // fix of fast sliding after multiple clicks
        if (clickDisabled) {return;}
        else {
            clickDisabled = true;
            clearInterval(slideShow);
            spin();
            slideShow = setInterval(spin, 4000);
            setTimeout(function() {clickDisabled = false;}, 2000);
        }
    }
}

我的想法是我有一个带旋转木马幻灯片的列表，我用setInterval重新排列这些幻灯片。通过在CSS中传输并改变滑块的边缘来实现平滑的滑动过渡 - 因此过渡使其平滑滑动。

自动旋转工作正常并没有问题，关键是要手动更改幻灯片，使用左右按钮。问题是，如果没有一个非常奇怪的（对我来说）拐杖，它就不会工作。它在代码中标记（第28行）。似乎有些事情阻止了过渡到完成，没有那个拐杖图像改变而没有过渡。我也非常感谢有关按钮的临时阻止onclick事件的想法的评论，以防止多次点击时出现乱码和即时滑动。也许这是一个糟糕的方式？哪种方式可以更好？

Answer 1

你可以使用我建立的这个图像滑块......虽然它只适用于现代浏览器。

http://codepen.io/team/moderndeveloper/pen/MKgqzq

/* global Modernizr */

if (!Object.assign) {
  Object.defineProperty(Object, 'assign', {
    enumerable: false,
    configurable: true,
    writable: true,
    value: function(target) {
      'use strict';
      if (target === undefined || target === null) {
        throw new TypeError('Cannot convert first argument to object');
      }

      var to = Object(target);
      for (var i = 1; i < arguments.length; i++) {
        var nextSource = arguments[i];
        if (nextSource === undefined || nextSource === null) {
          continue;
        }
        nextSource = Object(nextSource);

        var keysArray = Object.keys(nextSource);
        for (var nextIndex = 0, len = keysArray.length; nextIndex < len; nextIndex++) {
          var nextKey = keysArray[nextIndex];
          var desc = Object.getOwnPropertyDescriptor(nextSource, nextKey);
          if (desc !== undefined && desc.enumerable) {
            to[nextKey] = nextSource[nextKey];
          }
        }
      }
      return to;
    }
  });
}

(function(window, document, Modernizr) {
  "use strict";

  var d = document;
  var transform = Modernizr.prefixed('transform');

  function ImageSliderIndicators(imageSlider, options) {
    this.imageSlider = imageSlider;
    this.options = Object.assign({}, ImageSliderIndicators.DEFAULTS, options || {});
    this.el = d.querySelector('.' + this.options.indicatorsClass);
    this.indicators = [].slice.call(d.querySelectorAll('.' + this.options.indicatorClass));

    this.imageSlider.el.addEventListener('positionChanged', this.onPositionChanged.bind(this));
    this.el.addEventListener('click', this.onIndicatorClick.bind(this), false);
    this.onPositionChanged();
  }

  ImageSliderIndicators.DEFAULTS = {
    indicatorsClass: 'ImageSlider-indicators',
    indicatorClass: 'ImageSlider-indicator',
    indicatorActiveClass: 'ImageSlider-indicator--is-active'
  };

  ImageSliderIndicators.prototype.onIndicatorClick = function onIndicatorClick(event) {
    var position = this.indicators.indexOf(event.target);
    if (position !== -1) {
      this.imageSlider.goto(position);
    }
  };

  ImageSliderIndicators.prototype.onPositionChanged = function onPositionChanged() {
    var self = this;
    this.indicators.forEach(function(element, index) {
      var action = index === self.imageSlider.position ? 'add' : 'remove';
      element.classList[action](self.options.indicatorActiveClass);
    });
  };

  function ImageSlider(options) {
    this.options = Object.assign({}, ImageSlider.DEFAULTS, options || {});
    this.position = 0;
    this.el = d.querySelector('.' + this.options.imageSliderClass);
    this.items = d.querySelector('.' + this.options.itemsClass);
    this.itemCount = d.querySelectorAll('.' + this.options.itemClass).length;
    this.scroller = d.querySelector('.' + this.options.scrollerClass);
    this.previousButton = d.querySelector('.' + this.options.previousButtonClass);
    this.nextButton = d.querySelector('.' + this.options.nextButtonClass);
    this.indicators = new ImageSliderIndicators(this, this.options.indicators);

    window.addEventListener('resize', this.render.bind(this));
    this.nextButton && this.nextButton.addEventListener('click', this.next.bind(this));
    this.previousButton && this.previousButton.addEventListener('click', this.previous.bind(this));
  }

  ImageSlider.DEFAULTS = {
    imageSliderClass: 'ImageSlider',
    itemsClass: 'ImageSlider-items',
    itemClass: 'ImageSlider-item',
    scrollerClass: 'ImageSlider-scroller',
    previousButtonClass: 'js-ImageSlider-button--previous',
    nextButtonClass: 'js-ImageSlider-button--next'
  };

  ImageSlider.prototype.render = function render() {
    this.items.style[transform] = 'translate3d(' + (-this.position * this.items.offsetWidth) + 'px,0,0)';
  };

  ImageSlider.prototype.goto = function goto(position) {
    var event = d.createEvent('Event');
    event.initEvent('positionChanged', true, true);
    this.position = position;
    this.el.dispatchEvent(event);
    this.render();
  };

  ImageSlider.prototype.previous = function previous() {
    this.goto((this.position + (this.itemCount - 1)) % this.itemCount);
  };

  ImageSlider.prototype.next = function next() {
    this.goto((this.position + 1) % this.itemCount);
  };

  window.ImageSlider = ImageSlider;

}).call(this, window, window.document, Modernizr);

new ImageSlider();

Answer 2

为简单起见……图像、css 和 javascript 都在完全相同的时间呈现。因此转换无法发生，因为在转换运行时，图像已经具有您要“更改它”的值。

它的呈现是在添加值之后进行的，因此没有过渡。在这种情况下，使用 setTimeout 是相当标准的。但是，您应该意识到，如果某人的互联网连接速度较慢，那么 1/1000 秒的超时可能并不总是足够的。

正确的解决方案是，不要使用 javascript 更改样式，而是创建一个覆盖默认值的类，并使用 javascript 来切换您的类。

希望这实际上是您问题的答案，而不仅仅是我指出您使用预先存在的解决方案。

不过，就我个人而言，我完全按照您在做的事情做，就像我自己的轮播示例中所见：

/* set each image except first to not display */  
  document.querySelectorAll('.imgContainer div:not(:nth-child(1))').forEach(function(el) {
    el.style.display = 'none';
    el.style.opacity =  0;
  });

/* set onclick event for navigation dots */
  var dotty = document.querySelectorAll('ul li');
  for (var i = 0; i < dotty.length; i++) {
    dotty[i].addEventListener("click", contentChanger);
  }

/* rotate function */
  function contentChanger(evt) {
    var id = evt.target.id;
    x = evt.target.id;
    [].forEach.call(document.querySelectorAll('li'), function (el) {
      el.classList.remove('active');
    });
    evt.target.classList.add('active');
    document.querySelectorAll('.imgContainer div:not(:nth-child(' + id + '))').forEach(function(el) {
      el.style.display = 'none';
      el.style.opacity = '0';
    });
    document.querySelector('.imgContainer div:nth-child(' + id + ')').style.display = 'block';
    setTimeout(function(){
      document.querySelector('.imgContainer div:nth-child(' + id + ')').style.opacity =  1;
    }, 50);
  }

/* only required to automate rotation leave this code out if you want only a click navigation. */
  function clickIt(i) {
    document.querySelector('ul li:nth-child('+i+')').click();
  }
  var x = 0;
  setInterval(function(){
    x++;
    if (x > dotty.length) { x = 1; }
    clickIt(x);
  }, 5000);

https://codepen.io/billy-bucks/pen/RwKRyEx

纯JS Carousel bug

2 个答案: