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  • JS案例:轮播图(面向对象),最终版(注释全面)

    Html:

    <!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>Carousel</title>
        <script src="js/Carousel.js"></script>
        <style></style>
      </head>
    
      <body>
        <script>
          var arr = ["img/left.png", "img/right.png"]; //左右按钮
          var arr1 = [
            "img/a.png",
            "img/b.png",
            "img/c.png",
            "img/d.png",
            "img/e.png"
          ]; //新建源
          var arr2 = [
            "img/1.jpg",
            "img/2.jpg",
            "img/3.jpg",
            "img/4.jpg",
            "img/5.jpg",
            "img/6.jpg",
            "img/7.jpg"
          ]; //新建源
          var arr3 = ["img/aaa.jpg", "img/bbb.jpg", "img/ccc.jpg"]; //新建源
          var carousel = new Carousel(document.body, arr1, arr); //实例化轮播图
          var carousel2 = new Carousel(document.body, arr2, arr); //实例化轮播图
          var carousel3 = new Carousel(document.body, arr3, arr); //实例化轮播图
          carousel.autoPlay = true; //自动播放
          carousel2.autoPlay = true; //自动播放
          carousel3.autoPlay = true; //自动播放
          // carousel.heightValue = 600;//高宽可控
          // carousel3.widthValue =1600;//高宽可控
          animate();
    
          function animate() {
            //用一个动画函数控制轮播
            requestAnimationFrame(animate);
            carousel.animate();
            carousel2.animate();
            carousel3.animate();
          }
        </script>
      </body>
    </html>
    

    Js:

    var Carousel = (function () {
        var liStyle = { //初始化下面的小点样式
             "20px",
            height: "20px",
            borderRadius: "20px",
            backgroundColor: "rgba(240,137,137,0.3)",
            border: "1px solid #F08989",
            float: "left",
            lineHeight: "20px",
            textAlign: "center",
            marginLeft: "20px",
            color: "white"
        };
        var ulStyle = { //小点盒子
            margin: 0,
            padding: 0,
            listStyle: "none",
            position: "absolute",
            bottom: "20px"
        };
        var imgConStyle = { //图片盒子
            position: "absolute",
            left: "0px"
        };
        var maskDivStyle = { //最大的盒子
            overflow: "hidden",
            position: "relative",
            margin: "auto",
            backgroundColor: "antiquewhite"
        };
        //功能:实现高宽可改,图片预加载,可换图片源
        function Carousel(parent, list, btnList) {
            this.init(parent, btnList); //入口函数
            this.sourse = list; //引入图片源
        }
        Carousel.prototype = {
            loadImg: null, //正在加载的图片
            imgList: [], //加载的图片
            carouselBox: null, //装图片的盒子(最大的盒子)
            _ 0, //可修改的宽
            _height: 0, //可修改的高
            _sourse: [], //加载图片的源(路径)
            bool: false, //是否允许轮播
            index: 0, //当前加载图片的索引
            direct: "", //轮播方向
            speed: 30, //轮播的速度
            autoPlay: false, //是否自动轮播
            dotLi: null, //小点,根据源的图片数切换
            autoTime: 200, //自动轮播时间间隔,以每帧乘以200计算
            set sourse(value) { //设置切换的源时初始化其他属性
                if (!value || !Array.isArray(value) || !value.length) return; //当源不是数组或者为空时,截断并跳出
                this.widthValue = 0;
                this.heightValue = 0; //初始化宽高
                if (this.loadImg) { //初始化加载的图片,设为空
                    this.loadImg.removeEventListener("load", this.loadImgHandler);
                }
                this.imgList.length = 0; //清空图片列表
                this._sourse = value; //传入源
                this.reLoadImg(value); //执行加载图片
            },
            get sourse() {
                return this._sourse;
            },
            set widthValue(value) {
                this._width = value; //根据传入的宽度改变轮播图宽度
                if (this._width === 0) return;
                this.carouselBox.style.width = value + "px"; //每次更新,轮播图宽度改变
                var ul = this.carouselBox.lastElementChild; //初始化,装小点的盒子
                ul.style.left = (value - ul.offsetWidth) / 2 + "px"; // 当宽度改变时,小点自适应(定位在盒子宽度中间)
            },
            get widthValue() {
                return this._width;
            },
            set heightValue(value) { //根据传入的高度改变轮播图高度
                this._height = value;
                if (this._height === 0) return;
                this.carouselBox.style.height = value + "px";
                this.carouselBox.firstElementChild.style.height = value + "px"; //每次更新,轮播图高度改变
                this.carouselBox.children[1].style.top = this.carouselBox.children[2].style.top = (this.heightValue - this.carouselBox.children[1].offsetHeight) / 2 + "px"; // 当宽度改变时,左右按钮自适应(定位在盒子高度中间)
            },
            get heightValue() {
                return this._height;
            },
            reLoadImg: function (list) {
                var img = new Image(); //生成初始图片
                img.addEventListener("load", this.loadImgHandler); //图片加载完成后,执行下一张图片加载
                img.self = this;
                img.num = 0; //当前图片索引
                img.list = list;
                img.imgList = []; //图片列表初始
                img.src = list[img.num]; //通过事件传数据
            },
            loadImgHandler: function (e) {
                this.imgList.push(this.cloneNode(false)); //图片列表放入被加载的图片
                this.num++; //下一张图片索引
                if (this.num > this.list.length - 1) { //当全部加载完成后,继续执行其他函数
                    this.self.imgLoadFinish(this.imgList);
                    return;
                }
                this.src = this.list[this.num]; //否则继续加载
            },
            init: function (parent, btnList) { //入口函数
                if (!this.carouselBox) { //保证对象单例
                    this.carouselBox = document.createElement("div"); //装图片的盒子(最大的盒子)
                    var imgBox = document.createElement("div"); //加载图片的盒子,装在最大的盒子里,控制图片切换和移动
                    this.carouselBox.appendChild(imgBox);
                    for (var i = 0; i < btnList.length; i++) { //加载按钮
                        var btimg = new Image();
                        btimg.src = btnList[i];
                        this.carouselBox.appendChild(btimg);
                        if (i === 0) { //设置位置
                            btimg.style.left = "10px";
                            btimg.style.position = "absolute";
                        } else {
                            btimg.style.right = "10px";
                            btimg.style.position = "absolute";
                        }
                        btimg.self = this;
                        this.carouselBox.self = this;
                        this.carouselBox.addEventListener("mouseenter", this.isAuto); //控制开启关闭自动轮播
                        this.carouselBox.addEventListener("mouseleave", this.isAuto);
                        btimg.addEventListener("click", this.changeImgHandler); //加载点击事件
                    }
                    var ul = document.createElement("ul"); //小点盒子
                    Object.assign(ul.style, ulStyle); //设置样式
                    Object.assign(this.carouselBox.style, maskDivStyle); //设置样式
                    Object.assign(imgBox.style, imgConStyle); //设置样式
                    this.carouselBox.appendChild(ul);
                    parent.appendChild(this.carouselBox);
                }
                return this.carouselBox;
            },
            imgLoadFinish: function (imgList) { //图片加载完成后执行,传入图片列表
                this.imgList = imgList;
                var imgCon = this.carouselBox.firstElementChild; //初始化小点盒子和图片盒子(不是最大的盒子)
                var ul = this.carouselBox.lastElementChild;
                this.clearNode(imgCon); //清除子元素方法(初始化)
                this.clearNode(ul);
                for (var i = 0; i < this.imgList.length; i++) { //创建小点
                    var li = document.createElement("li");
                    ul.appendChild(li);
                    Object.assign(li.style, liStyle); //小点样式
                }
                ul.style.left = (this.widthValue - ul.offsetWidth) / 2 + "px"; //小点盒子的默认位置
                imgCon.appendChild(this.imgList[0]);
                ul.self = this;
                ul.addEventListener("click", this.changeDot); //小点点击事件
                if (this.widthValue === 0) {
                    this.widthValue = this.imgList[0].width; //当传入的宽为0时,将宽设置为默认宽
                } else {
                    this.carouselBox.style.width = this.widthValue + "px"; //否则设置为改变的宽
                    this.setSize(imgCon, this.widthValue, 0); //调用下面的设置宽高方法,将图片宽高重设
                }
                if (this.heightValue === 0) { //同上
                    this.heightValue = this.imgList[0].height;
                } else {
                    this.carouselBox.style.height = this.heightValue + "px";
                    imgCon.firstElementChild.style.height = this.heightValue + "px";
                    this.setSize(imgCon, 0, this.heightValue);
                }
                this.dotColor(); //执行小点样式切换
                this.carouselBox.children[1].style.top = this.carouselBox.children[2].style.top = (this.heightValue - this.carouselBox.children[1].offsetHeight) / 2 + "px"; //按钮位置重设,自适应
            },
            setSize: function (con, w, h) { //设置子元素宽高函数
                for (var i = 0; i < con.children.length; i++) {
                    if (w) {
                        con.children[i].style.width = w + "px";
                    }
                    if (h) {
                        con.children[i].style.height = h + "px";
                    }
                }
            },
            clearNode: function (node) { //清除子元素函数
                var len = node.children.length;
                for (var i = 0; i < len; i++) {
                    node.firstElementChild.remove();
                }
            },
            changeImgHandler: function (e) {
                if (this.self.bool) return; //当点击一次后,执行完一次轮播才能再次点击
                if (this.style.left === "10px") { //根据位置判断左右按钮
                    this.self.direct = "right"; //改变轮播方向
                    this.self.index--; //索引值减一,即加载上一张图片
                    if (this.self.index < 0) { //当减到0时,加载最后一张
                        this.self.index = this.self.imgList.length - 1;
                    }
                } else if (this.style.right === "10px") { //同上(相反)
                    this.self.direct = "left";
                    this.self.index++;
                    if (this.self.index > this.self.imgList.length - 1) {
                        this.self.index = 0;
                    }
                }
                this.self.creatNextPic(); //跳到加载下一张图片函数
            },
            creatNextPic: function () {
                if (this.direct !== "left" && this.direct !== "right") return; //当未点击左或者右时跳出
                var imgCount = this.carouselBox.firstElementChild; //获取装图片的盒子(控制图片轮播的盒子,不是最大的盒子)
                if (this.direct === "left") { //当方向为左,即单击了左按钮
                    imgCount.appendChild(this.imgList[this.index]); //装图片的盒子根据当前索引加入图片(插在后面)
                    imgCount.style.width = this.widthValue * 2 + "px"; //装图片的盒子宽度设置为图片宽度的两倍(放下两张图片)
                    imgCount.style.left = 0; //初始盒子位置
                } else {
                    imgCount.insertBefore(this.imgList[this.index], imgCount.firstElementChild); //装图片的盒子根据当前索引加入图片(插在前面)
                    imgCount.style.width = this.widthValue * 2 + "px"; //装图片的盒子宽度设置为图片宽度的两倍(放下两张图片)
                    imgCount.style.left = -this.widthValue + "px"; //初始盒子位置
                }
                if (!this.widthValue) { //重设宽高
                    this.imgList[this.index].style.width = this.widthValue + "px";
                }
                if (!this.heightValue) {
                    this.imgList[this.index].style.height = this.heightValue + "px";
                }
                this.dotColor(); //切换小点颜色
                this.bool = true; //允许下一次点击
            },
            movePic: function () { //轮播动画
                if (!this.bool) return; //若没加载好下一张,跳出
                if (this.direct !== "left" && this.direct !== "right") {
                    this.bool = false;
                    return;
                } //若没单击,跳出
                var imgCount = this.carouselBox.firstElementChild; //初始图片盒子
                if (this.direct === "left") { //轮播方向为左时,以设定的速度向左移动
                    imgCount.style.left = imgCount.offsetLeft - this.speed + "px";
                    if (imgCount.offsetLeft <= -this.widthValue) { //当后面的图片移动到0时停止
                        imgCount.firstElementChild.remove(); //删除左边的图片
                        imgCount.style.left = 0 + "px"; //初始化盒子的位置
                        this.direct = ""; //制空方向,将轮播开关关闭,需要下次点击才打开
                        this.bool = false;
                    }
                } else { //轮播方向为右时,以设定的速度向右移动
                    imgCount.style.left = imgCount.offsetLeft + this.speed + "px";
                    if (imgCount.offsetLeft >= 0) { //当前面的图片移动到0时停止
                        imgCount.lastElementChild.remove(); //删除右边的图片
                        imgCount.style.left = 0 + "px"; //初始化盒子的位置
                        this.direct = ""; //制空方向,将轮播开关关闭,需要下次点击才打开
                        this.bool = false;
                    }
                }
            },
            changeDot: function (e) {
                if (this.self.bool) return; //点击按钮或小点时,跳出
                if (e.target instanceof HTMLUListElement) return; //没有点击小点(li)时跳出
                var arr = Array.from(this.children); //小点数组化
                var count = arr.indexOf(e.target); //查找小点索引
                if (count === this.self.index) return; //点击自身时跳出
                if (count > this.self.index) { //当点击的小点大于当前小点时,将方向置为左
                    this.self.direct = "left";
                } else if (count < this.self.index) { //反之向右
                    this.self.direct = "right";
                }
                this.self.index = count; //将图片索引设置为点击小点索引
                this.self.creatNextPic(); //创建下张图片
                this.self.dotColor(); //改变小点样式
            },
            dotColor: function () { //前一个小点背景透明
                if (this.dotLi) {
                    this.dotLi.style.backgroundColor = "rgba(240,137,137,0.3)";
                } //将被切换的小点赋值给当前小点,使其根据计数器切换
                this.dotLi = this.carouselBox.lastElementChild.children[this.index];
                this.dotLi.style.backgroundColor = "rgba(240,137,137,1)";
            },
            isAuto: function (e) { //根据鼠标是否进入轮播图判断是否自动轮播
                if (e.type === "mouseenter") {
                    this.self.autoPlay = false;
                } else {
                    this.self.autoPlay = true;
                }
            },
            carouselAuto: function () { //自动轮播
                if (!this.autoPlay) return; //当计数器为0时执行一次
                this.autoTime--; //每帧使计时器减一
                if (this.autoTime > 0) return;
                this.autoTime = 200;
                this.direct = "left"; //默认自动轮播方向
                this.index++;
                if (this.index > this.imgList.length - 1) {
                    this.index = 0;
                }
                this.creatNextPic(); //创建下一张图
            },
            animate: function () { //单一动画,每帧执行一次,将动画放在一个函数内
                this.movePic();
                this.carouselAuto();
            }
        };
        Carousel.prototype.constructor = Carousel;
        return Carousel;
    })();
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  • 原文地址:https://www.cnblogs.com/HelloWorld-Yu/p/10193682.html
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