全功能轮播组件封装（详细注释）

布满荆棘的人生 2022-02-25 16:56 196阅读 0赞

在线演示：[http://js.jirengu.com/ferojuvonu/2/edit?html,js,output][http_js.jirengu.com_ferojuvonu_2_edit_html_js_output]

<!DOCTYPE html>
    <html lang="en">
      <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <meta http-equiv="X-UA-Compatible" content="ie=edge" />
        <title>Document</title>
        <style> .slider { overflow: hidden; position: relative; } .slider .slider-pager { position: absolute; bottom: 5px; left: 50%; transform: translateX(-50%); } .slider .slider-pager .active { padding-top: 5px; } .slider .slider-pre { position: absolute; top: 50%; left: 5px; transform: translateY(-50%); } .slider .slider-next { position: absolute; top: 50%; right: 5px; transform: translateY(-50%); } .slider ul { display: flex; list-style: none; margin: 0; padding: 0; transition: transform 0.5s; } ul img { vertical-align: top; } </style>
      </head>
      <body>
        <div class="slider">
          <ul>
            <li><img src="https://i.loli.net/2018/01/03/5a4c93e92b0e1.png" /></li>
            <li>
              <img src="https://i.loli.net/2018/01/03/5a4c93e931f93.png" />
            </li>
            <li>
              <img src="https://i.loli.net/2018/01/03/5a4c93e938b6b.png" />
            </li>
          </ul>
        </div>
      </body>
      <script src="./SliderController.js"></script>
    </html>

/** * 具有翻页器，页面指示器，自动播放功能的轮播图 */
    class Slider { 
      constructor(options) { 
        this.options = options;
        this.element = document.querySelector(this.options.selector);
        this.init();
      }
    
      //初始化轮播图
      init() { 
        //根据单个内容宽度设定容器宽度
        this.width = this.element.querySelector("li").clientWidth;
        this.length = this.element.querySelectorAll("li").length;
        this.element.style.width = this.width + "px";
        this.currentIndex = 0;
        if (this.options.controls) { 
          this.renderControls();
        }
        if (this.options.pager) { 
          this.renderPager();
        }
        if (this.options.autoPlay) { 
          this.autoPlay();
        }
      }
    
      //渲染轮播页指示器
      renderPager() { 
        //渲染单个指示点，并绑定事件
        const renderItem = index => { 
          const item = document.createElement("li");
          item.style.margin = "0 2px";
          item.innerText = "_";
          item.onclick = () => { 
            this.go(index);
          };
          return item;
        };
        const pager = document.createElement("ul");
        pager.setAttribute("class", "slider-pager");
        for (let i = 0; i < this.length; i++) { 
          pager.appendChild(renderItem(i));
        }
        this.element.appendChild(pager);
        this.pagerRefresh(); //首次渲染时激活active样式
      }
    
      //根据currentIndex渲染被激活的指示点
      pagerRefresh() { 
        if (!this.options.pager) return;
        const items = this.element.querySelector(".slider-pager").children;
        Array.prototype.forEach.call(items, i => { 
          i.classList.remove("active");
        });
        items[this.currentIndex].classList.add("active");
      }
    
      //渲染左右翻页器,默认按钮为“<>”
      renderControls(preDiv, nextDiv) { 
        const preBtn = document.createElement("span");
        preBtn.setAttribute("class", "slider-pre");
        preBtn.innerText = preDiv || "<";
        preBtn.onclick = () => this.go(this.currentIndex - 1);
        const nextBtn = document.createElement("span");
        nextBtn.setAttribute("class", "slider-next");
        nextBtn.innerText = nextDiv || ">";
        nextBtn.onclick = () => this.go(this.currentIndex + 1);
        this.element.appendChild(preBtn);
        this.element.appendChild(nextBtn);
      }
    
      //使用定时器自动播放
      play() { 
        console.log("play");
        this.timerID = setInterval(() => { 
          this.go(this.currentIndex + 1);
        }, 2000);
      }
    
      //清除定时器，止自动播放
      stop() { 
        console.log("stop");
        clearInterval(this.timerID);
      }
    
      //自动播放
      autoPlay() { 
        this.play();
        this.element.addEventListener("mouseenter", () => this.stop());
        this.element.addEventListener("mouseleave", () => this.play());
      }
    
      //核心方法，跳转至指定页数
      go(index) { 
        length = this.length;
        index = index >= length ? 0 : index < 0 ? length - 1 : index; //判断跳转的位置是否超出范围（边缘处理）
        console.log(index);
        this.element.querySelector(
          "ul"
        ).style.cssText = `transform:translateX(-${ index * this.width}px)`;
        this.currentIndex = index;
        this.pagerRefresh();
      }
    }
    
    new Slider({ 
      selector: ".slider", //轮播组件的位置
      autoPlay: true, //自动播放
      pager: true, //是否显示页面跳转指示器
      controls: true //是否显示上一页下一页控制器
    });

[http_js.jirengu.com_ferojuvonu_2_edit_html_js_output]: http://js.jirengu.com/ferojuvonu/2/edit?html,js,output