如何将HTML CSS图像滑块转换为Angular图像滑块？

Question

我正试图从头开始在 Angular 中实现一个图片轮播器，并尝试复制一个基于 w3school 的图片轮播器。

下面是我在 Angular 中的实现，请问有谁可以指导我如何使用 Angular 实现呢？

您可以在这里查找 stackblitz 链接

component.html

<div class="slideshow-container" #myDiv>

    <div class="mySlides fade">
        <div class="numbertext">1 / 3</div>
        <img src="https://img.adaptivereso.com/https://stellarmls-propertyresi.s3.us-west-002.backblazeb2.com/314a10f7-07d4-4d9e-b8ea-be44be55ab35.jpeg/?rwidth=300&rheight=200&type=jpg" style="width:100%">
        <div class="text">Caption Text</div>
    </div>

    <div class="mySlides fade" >
        <div class="numbertext">2 / 3</div>
        <img src="https://img.adaptivereso.com/https://stellarmls-propertyresi.s3.us-west-002.backblazeb2.com/cd7c5e85-d528-4d10-a635-ace77aaef77d.jpeg/?rwidth=300&rheight=200&type=jpg" style="width:100%">
        <div class="text">Caption Two</div>
    </div>

    <div class="mySlides fade">
        <div class="numbertext">3 / 3</div>
        <img src="https://img.adaptivereso.com/https://stellarmls-propertyresi.s3.us-west-002.backblazeb2.com/314a10f7-07d4-4d9e-b8ea-be44be55ab35.jpeg/?rwidth=300&rheight=200&type=jpg" style="width:100%">
        <div class="text">Caption Three</div>
    </div>

    <a class="prev" (click)="plusSlides(-1)">&#10094;</a>
    <a class="next" (click)="plusSlides(1)">&#10095;</a>

</div>
<br>

<div style="text-align:center">
    <span class="dot" (click)="currentSlide(1)"></span>
    <span class="dot" (click)="currentSlide(2)"></span>
    <span class="dot" (click)="currentSlide(3)"></span>
</div>

component.ts

import { Component, OnInit, ViewChild, ElementRef, ViewChildren, QueryList } from '@angular/core';

@Component({
  selector: 'app-custom-gallery',
  templateUrl: './custom-gallery.component.html',
  styleUrls: ['./custom-gallery.component.css']
})
export class CustomGalleryComponent implements OnInit {

  slideIndex:number = 1;
  constructor (public elementRef: ElementRef) { }

  ngOnInit(): void {
    this.showSlides(this.slideIndex);
  }

  plusSlides(n) {
    this.showSlides(this.slideIndex += n);
  }
  
  currentSlide(n) {
    console.log(n)
    this.showSlides(this.slideIndex = n);
  }

  showSlides(n) {
    var i;
    var slides = document.getElementsByClassName("mySlides");
    var dots = document.getElementsByClassName("dot");
    if (n > slides.length) {this.slideIndex = 1}    
    if (n < 1) {this.slideIndex = slides.length}
    for (i = 0; i < slides.length; i++) {
      console.log(typeof slides[i]);
        // slides[i].style.display = "none";
    }
    for (i = 0; i < dots.length; i++) {
        dots[i].className = dots[i].className.replace(" active", "");
    }
    // slides[this.slideIndex-1].style.display = "block";  
    dots[this.slideIndex-1].className += " active";
  }

}

component.css

* {box-sizing: border-box}
body {font-family: Verdana, sans-serif; margin:0}
.mySlides {display: none}
img {vertical-align: middle;}

/* Slideshow container */
.slideshow-container {
  max-width: 1000px;
  position: relative;
  margin: auto;
}

/* Next & previous buttons */
.prev, .next {
  cursor: pointer;
  position: absolute;
  top: 50%;
  width: auto;
  padding: 16px;
  margin-top: -22px;
  color: white;
  font-weight: bold;
  font-size: 18px;
  transition: 0.6s ease;
  border-radius: 0 3px 3px 0;
  user-select: none;
}

/* Position the "next button" to the right */
.next {
  right: 0;
  border-radius: 3px 0 0 3px;
}

/* On hover, add a black background color with a little bit see-through */
.prev:hover, .next:hover {
  background-color: rgba(0,0,0,0.8);
}

/* Caption text */
.text {
  color: #f2f2f2;
  font-size: 15px;
  padding: 8px 12px;
  position: absolute;
  bottom: 8px;
  width: 100%;
  text-align: center;
}

/* Number text (1/3 etc) */
.numbertext {
  color: #f2f2f2;
  font-size: 12px;
  padding: 8px 12px;
  position: absolute;
  top: 0;
}

/* The dots/bullets/indicators */
.dot {
  cursor: pointer;
  height: 15px;
  width: 15px;
  margin: 0 2px;
  background-color: #bbb;
  border-radius: 50%;
  display: inline-block;
  transition: background-color 0.6s ease;
}

.active, .dot:hover {
  background-color: #717171;
}

/* Fading animation */
.fade {
  -webkit-animation-name: fade;
  -webkit-animation-duration: 1.5s;
  animation-name: fade;
  animation-duration: 1.5s;
}

@-webkit-keyframes fade {
  from {opacity: .4} 
  to {opacity: 1}
}

@keyframes fade {
  from {opacity: .4} 
  to {opacity: 1}
}

/* On smaller screens, decrease text size */
@media only screen and (max-width: 300px) {
  .prev, .next,.text {font-size: 11px}
}

- Sangram Badi

---

你的 StackBlitz 有什么问题吗？我只看到了三个点。 - wlf

@wlf它正在显示3个点，所以这是我得到的错误，但预期输出应该是图像滑块。 - Sangram Badi

它没有显示任何内容，因为您在所有图像上都有 display: none;。但我认为您的一般方法不正确。您想要一个 ImageSliderComponent，其中一种方法是将其作为输入数组获取图像。该组件将封装导航图像等功能。 - wlf

所以最初我将所有内容都设置为display:none，然后在单击箭头时，逐个显示图像。 在这里我遇到了一个错误：slides[i].style.display = "none"。 - Sangram Badi

Answer 1

这里有一种方法可以使用:

创建一个 ImageSlider 组件，它接受一个 images 列表作为输入，并跟踪当前幻灯片。

export class ImageSliderComponent {
  @Input() images: string[];

  slideIndex: number = 0;

  changeSlide(n: number) {
    this.slideIndex += n;
  }
}

在模板中，仅显示活动幻灯片（参考 src绑定）：

<div class="slideshow-container" #myDiv>
  <div class="mySlides fade">
    <div class="numbertext">{{ slideIndex + 1}} / {{ images.length }}</div>
    <img
    [src]="images[slideIndex]" 
    style="width:100%"
  />
    <div class="text">Caption Text</div>
  </div>

  <a class="prev" (click)="changeSlide(-1)">&#10094;</a>
  <a class="next" (click)="changeSlide(1)">&#10095;</a>
</div>

使用组件的方法如下：

<app-image-slider [images]="[  'http://images.com/image1.jpg',  'http://images.com/image1.jpg',  'http://images.com/image3.jpg']"></app-image-slider>

Stackblitz: https://stackblitz.com/edit/angular-ivy-x9nk16?file=src%2Fapp%2Fimage-slider.component.ts

注意：

• 在 Angular 应用程序中，应避免使用 ElementRef、getElementsByClassName 等方法，这通常表示您没有按照 Angular 的惯例使用。

- wlf