Swiper Slider...removing箭头

Question

我想删除箭头上的iDangerous滑块，除非箭头是必要的。例如，我目前有4个并排的图像，如果用户在移动设备(或较小的计算机屏幕)上，并且显示的图像少于4个，那么我希望箭头显示出来，以便用户可以滚动。但是，如果所有4个图像都显示了，那么我不希望箭头出现。

我试着用jQuery来做这件事，但是我所做的都不起作用。

<script>
var swiper = new Swiper('.swiper-container', {
                slidesPerView: 4,
                slidesPerGroup: 4,
                loopedSlides: 4,
                centeredSlides: false,
                spaceBetween: 0,
                grabCursor: true,
                loop:false,
                pagination: '.swiper-pagination',
                paginationClickable: true,
                breakpoints: {
                    1200: {
                        slidesPerView: 4,
                        loopedSlides: 4,
                        spaceBetween: 10
                    },
                    1024: {
                        slidesPerView: 3,
                        loopedSlides: 3,
                        spaceBetween: 10
                    },
                    768: {
                        slidesPerView: 2,
                        loopedSlides: 2,
                        spaceBetween: 10
                    },
                    675: {
                        slidesPerView: 1,
                        loopedSlides: 1,
                        spaceBetween: 20
                    }
                }
            });
document.querySelector('.prepend-2-slides').addEventListener('click', function (e) {
  e.preventDefault();
  swiper.prependSlide([
    '<div class="swiper-slide">Slide ' + (--prependNumber) + '</div>',
    '<div class="swiper-slide">Slide ' + (--prependNumber) + '</div>'
    ]);
});
document.querySelector('.prepend-slide').addEventListener('click', function (e) {
  e.preventDefault();
  swiper.prependSlide('<div class="swiper-slide">Slide ' + (--prependNumber) + '</div>');
});
document.querySelector('.append-slide').addEventListener('click', function (e) {
  e.preventDefault();
  swiper.appendSlide('<div class="swiper-slide">Slide ' + (++appendNumber) + '</div>');
});
document.querySelector('.append-2-slides').addEventListener('click', function (e) {
  e.preventDefault();
  swiper.appendSlide([
    '<div class="swiper-slide">Slide ' + (++appendNumber) + '</div>',
    '<div class="swiper-slide">Slide ' + (++appendNumber) + '</div>'
    ]);
});
var slides = document.querySelectorAll('.swiper-wrapper .swiper-slide');
var arrowPrev = document.querySelector('.swiper-button-prev');
var arrowNext = document.querySelector('.swiper-button-prev');

if (slides.length < 4) {
arrowPrev.style.display = 'none';
arrowNext.style.display = 'none';
 }
 </script>

这不起作用，事实上，它弄乱了滑块(而不是有4个独立的图像，我在屏幕上有一个图像。然后我用下面的代码替换了最后一部分，它也将其更改为屏幕上的一个图像，箭头仍然在那里。

  var swiper__slidecount = mySwiper.slides.length;
    if (swiper__slidecount > 3) {
      $('.swiper-button-prev,.swiper-button-next').remove();
    }

这是一个link to the website这是一个JS Fiddle link.奇怪的是，在我的网站上运行的代码，不能在JS link to the website上运行，这让我更加困惑。

Answer 1

你可以检查它，我已经为你创建了一个片段，我会解释说，我已经创建了一个函数，检查视口时，其定义在滑动断点当视口小于1024，这是3幻灯片，然后箭头将出现一次是大于1024，然后箭头将消失，只要其4幻灯片如你所想。

小提琴https://jsfiddle.net/61LLnfh7/6/

​

var mySwiper = new Swiper('.swiper-container', {
  slidesPerView: 4,
  slidesPerGroup: 4,
  loopedSlides: 4,
  navigation: {
    nextEl: '.swiper-button-next',
    prevEl: '.swiper-button-prev',
  },
  breakpoints: {
    1200: {
      slidesPerView: 4,
      loopedSlides: 4,
      spaceBetween: 10
    },
    1024: {
      slidesPerView: 3,
      loopedSlides: 3,
      spaceBetween: 10
    },
    768: {
      slidesPerView: 2,
      loopedSlides: 2,
      spaceBetween: 10
    },
    675: {
      slidesPerView: 1,
      loopedSlides: 1,
      spaceBetween: 20,
    }
  },
  on: {
    init: function() {
			checkArrow();
    },
    resize: function () {
			checkArrow();
    }
  }
});

function checkArrow() {
  var swiperPrev = document.querySelector('.swiper-button-prev');
  var swiperNext = document.querySelector('.swiper-button-next');
  if ( window.innerWidth < 1024  ) {
    console.log('Success', window.innerWidth);
    swiperPrev.style.display = 'block';
    swiperNext.style.display = 'block';
  } else {
    swiperPrev.style.display = 'none';
    swiperNext.style.display = 'none';
  }
}

.swiper-wrapper .swiper-slide {
  background-color: #eee;
  height: 250px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.swiper-button-prev,
.swiper-button-next {
  display: none;
}

<link href="https://cdnjs.cloudflare.com/ajax/libs/Swiper/4.2.6/css/swiper.min.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Swiper/4.2.6/js/swiper.min.js"></script>

<!-- Slider main container -->
<div class="swiper-container">
    <!-- Additional required wrapper -->
    <div class="swiper-wrapper">
        <!-- Slides -->
        <div class="swiper-slide">Slide 1</div>
        <div class="swiper-slide">Slide 2</div>
        <div class="swiper-slide">Slide 3</div>
        <div class="swiper-slide">Slide 4</div>
        
    </div>
    <!-- If we need pagination -->
    <div class="swiper-pagination"></div>

    <!-- If we need navigation buttons -->
    <div class="swiper-button-prev"></div>
    <div class="swiper-button-next"></div>

</div>

​

Answer 2

不过，我设法用另一种方式让它正常工作。我只是想在导航箭头未被“禁用”时显示它们。

在Swiper API上，我们有disabledClass，这是当箭头被禁用时(不做导航，即滑块的开始或结束)时要应用的类。

navigation: {
    nextEl: '.swiper-button-next',
    prevEl: '.swiper-button-prev',
    disabledClass: 'disabled_swiper_button'
  },

然后在css方面只需简单地：

.disabled_swiper_button {
    opacity: 0;
    cursor: auto;
    pointer-events: none;
}

Answer 3

我的第一个想法是

console.log(slides);

并检查并查看它在运行时的编号。

还修复了控制台错误：

Uncaught TypeError: Cannot read property 'addEventListener' of null
at (index):449

似乎找不到此元素：

document.querySelector('.prepend-2-slides').addEventListener('click', function (e) {