> For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt.

# 九宫格抽奖

## 页面布局与样式

### 页面布局

- 默认九宫格图
  <img alt="原图.png" src={image0} />

- 九宫格占位图
  <img alt="奖品拼接图.png" src={image1} />

### HTML 页面代码

```html title="代码示例"
<!-- center为九宫格区域 -->
<div class="center">
    <!-- box为九个格子，DOM拼接区域 -->
    <ul id="box">
        <!-- li中下标从0开始，0-8共九个格子 -->
        <li class="prize jp-0 active">
            <!-- 动态获取奖品图标和文字描述 -->
            <img src="" draggable="false" />
            <p>xxxx</p>
        </li>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <!-- 其中下标为4的格子是最中心的按钮 -->
        <li class="no-price" id="drawBtn">
            <div>开始抽奖</div>
        </li>
        <li>5</li>
        <li>6</li>
        <li>7</li>
        <li>8</li>
    </ul>
</div>
```

### 页面样式

九宫格布局相关 CSS 页面样式

```css title="代码示例"
.center ul {
    box-sizing: border-box;
    padding: 15px;
    width: 100%;
    height: 100%;
}

ul li {
    float: left;
    box-sizing: border-box;
    width: 195px;
    height: 195px;
    background: #fff;
    border-radius: 6px;
    text-align: center;
}

ul li:nth-child(2),
ul li:nth-child(8) {
    margin: 0 15px;
}

ul li:nth-child(4),
ul li:nth-child(6) {
    margin: 15px 0;
}

ul li:nth-child(5) {
    cursor: pointer;
    margin: 15px;
    background: #f86f05;
}

ul li:nth-child(5):hover {
    opacity: 0.8;
}

ul li > img {
    margin-top: 20px;
    width: 104px;
    height: 104px;
}

ul li > p {
    line-height: 40px;
    font-size: 28px;
    color: #ff9f00;
}

ul li.no-price {
    padding: 15px 0;
}

ul li.no-price div {
    padding: 10px 16px;
    line-height: 60px;
    font-size: 54px;
    color: #fff;
    letter-spacing: 2px;
}

ul li.no-price p.tips {
    line-height: 30px;
    font-size: 16px;
    color: #fff;
    font-weight: bold;
    text-align: center;
}

#box li.active {
    background: #fcff76;
}
```

### 代码逻辑

Luck 幸运抽奖函数方法：

```javascript title="代码示例"
// 抽奖动画效果
var luck = {
    index: -1, //当前转动到哪,起点位置
    count: 0, //共有多少个位置
    timer: 0, //setTimeout的ID,用clearTimeout清除
    speed: 20, //初始化转动速度
    times: 0, //转动次数
    cycle: 25, //转动基本次数:即转动多少次之后进入抽奖环节
    prize: -1, //中奖位置
    init: function (id) {
        if ($("#" + id).find(".prize").length > 0) {
            $luck = $("#" + id);
            $units = $luck.find(".prize");
            this.obj = $luck;
            this.count = $units.length;
            $luck.find(".jp-" + this.index).addClass("active");
        }
    },
    roll: function () {
        var index = this.index;
        var count = this.count;
        var luck = this.obj;
        $(luck)
            .find(".jp-" + index)
            .removeClass("active");
        index += 1;
        if (index > count - 1) index = 0;
        $(luck)
            .find(".jp-" + index)
            .addClass("active");
        this.index = index;
        return false;
    },
    stop: function (index) {
        this.prize = index;
        return false;
    },
};
```

奖品列表 DOM 拼接：

```javascript title="代码示例"
/* 奖品列表排序 */
let sortList = function (data, el) {
    var str = "",
        sortArr = [];
    for (let i = 0, len = data.length; i < len; i++) {
        let tmp = data[i];
        if (i == 3) {
            sortArr[i] =
                `<li class="prize jp-7" data-gid="${tmp.goodGid}"><img src="${tmp.pic}" draggable="false"><p>${tmp.name}</p></li>`;
        } else if (i == 4) {
            sortArr[i] =
                `<li class="no-price" id="drawBtn"><div>开始抽奖</div><p class="tips">注：奖品以最终实物为准</p></li>`;
            sortArr[5] = `<li class="prize jp-3" data-gid="${tmp.goodGid}"><img src="${tmp.pic}" draggable="false"><p>${tmp.name}</p></li>`;
        } else if (i == 5) {
            sortArr[6] = `<li class="prize jp-6" data-gid="${tmp.goodGid}"><img src="${tmp.pic}" draggable="false"><p>${tmp.name}</p></li>`;
        } else if (i == 6) {
            sortArr[7] = `<li class="prize jp-5" data-gid="${tmp.goodGid}"><img src="${tmp.pic}" draggable="false"><p>${tmp.name}</p></li>`;
        } else if (i == 7) {
            sortArr[8] = `<li class="prize jp-4" data-gid="${tmp.goodGid}"><img src="${tmp.pic}" draggable="false"><p>${tmp.name}</p></li>`;
        } else {
            sortArr[i] =
                `<li class="prize jp-${i}" data-gid="${tmp.goodGid}"><img src="${tmp.pic}" draggable="false"><p>${tmp.name}</p></li>`;
        }
    }
    $("#" + el).html(sortArr.join(""));
    // 在拼接完页面之后再初始化抽奖逻辑函数，否则获取不到li的DOM节点列表
    luck.init("box");
};
```

时间、速度、中奖编号&中奖奖品下标控制：

```javascript title="代码示例"
/* 时间、速度、中奖编号控制 */
function roll() {
    luck.times += 1;
    luck.roll();
    if (luck.times > luck.cycle + 10 && luck.prize == luck.index) {
        clearTimeout(luck.timer);
        luck.prize = -1;
        luck.times = 0;
        click = false;
    } else {
        if (luck.times < luck.cycle) {
            luck.speed -= 20;
        } else if (luck.times == luck.cycle) {
            // 奖品位置下标
            if (prizeInfo.index != "") {
                luck.prize = prizeInfo.index;
            }
        } else {
            if (
                luck.times > luck.cycle + 10 &&
                ((luck.prize == 0 && luck.index == 7) ||
                    luck.prize == luck.index + 1)
            ) {
                luck.speed += 110;
            } else {
                luck.speed += 20;
            }
        }
        if (luck.speed < 40) luck.speed = 40;
        luck.timer = setTimeout(roll, luck.speed);
    }
    return false;
}
// 初始化点击事件为false，防止多次点击造成动画累积
var click = false;
```

点击抽奖实现：

```javascript title="代码示例"
/* 点击抽奖 */
$("#box").on("click", "li#drawBtn", function () {
    if (click) {
        return false;
    } else {
        $.post(`api`, { genre: 3, type: 2 }, function (res) {
            if (res.code == 1) {
                let data = res.result_data;
                let gId = data.goodGid,
                    pIndex = "";
                $("#prizeImg").attr("src", data.pic);
                $("#prizeTips").html(data.name);
                let arr = prizeList;
                for (let i = 0, len = arr.length; i < len; i++) {
                    let goodGid = arr[i]["goodGid"];
                    if (gId == goodGid) {
                        switch (i) {
                            case 3:
                                prizeInfo.index = 7;
                                break;
                            case 4:
                                prizeInfo.index = 3;
                                break;
                            case 5:
                                prizeInfo.index = 6;
                                break;
                            case 6:
                                prizeInfo.index = 5;
                                break;
                            case 7:
                                prizeInfo.index = 4;
                                break;
                            default:
                                prizeInfo.index = i;
                                break;
                        }
                        break;
                    }
                }
                // 抽奖
                luck.speed = 100;
                roll();
                click = true;
                let timer = setTimeout(function () {
                    clearTimeout(timer);
                    $("#mask").fadeIn();
                }, 4000);
                return false;
            } else {
                alert(res.message);
            }
        });
    }
});
```

## 抽奖逻辑与算法

### 抽奖模型和拼接模型

- 九宫格模型「图 1」
  <img alt="九宫格.png" src={image2} />

- 拼接图模型「图 2」
  <img alt="拼接图.png" src={image3} />

:::tip 提示
当动态实现九宫格奖品信息展示时，若想按照图 1 位置显示奖品信息，则此时需要换一下九宫格的位置。
替换位置为：4→8、6→4、8→6、9→5、5→○（○ 即抽奖按钮）
:::

### 封装奖品列表排序方法

```javascript title="代码示例"
/* 九宫格奖品列表排序 */
function sortList(data, el) {
    var ID4,
        str = "";
    for (var i = 0; i < data.length; i++) {
        if (i == 3) {
            //3->7
            str +=
                "<div class='prize jp-" +
                7 +
                "'><img src='" +
                data[i].pic +
                "'><p>" +
                data[i].name +
                "</p></div>";
        } else if (i == 4) {
            // 4
            ID4 = 4;
            str += "<div id='Btn'><p>开始抽奖</p></div>";
        } else if (i == 5) {
            //5->3
            str +=
                "<div class='prize jp-" +
                3 +
                "'><img src='" +
                data[i].pic +
                "'><p>" +
                data[i].name +
                "</p></div>";
        } else if (i == 7) {
            //7->5、8->4
            str +=
                "<div class='prize jp-" +
                5 +
                "'><img src='" +
                data[i].pic +
                "'><p>" +
                data[i].name +
                "</p></div><div class='prize jp-" +
                ID4 +
                "'><img src='" +
                data[ID4].pic +
                "'><p>" +
                data[ID4].name +
                "</p></div>";
        } else {
            str +=
                "<div class='prize jp-" +
                i +
                "'><img src='" +
                data[i].pic +
                "'><p>" +
                data[i].name +
                "</p></div>";
        }
    }
    $("#" + el).html(str);
}

//初始化抽奖按钮点击属性
var click = false;
```

### 初始全局变量（获奖奖品下标）

```javascript title="代码示例"
// 奖品列表
var prizeList,
    // 中奖下标（在奖品列表中的下标）
    prizeObj = {
        pIndex: "",
    };
```

### 奖品动画初始化

```javascript title="代码示例"
var luck = {
    index: -1, //当前转动到哪,起点位置
    count: 0, //共有多少个位置
    timer: 0, //setTimeout的ID,用clearTimeout清除
    speed: 20, //初始化转动速度
    times: 0, //转动次数
    cycle: 25, //转动基本次数:即转动多少次之后进入抽奖环节
    prize: -1, //中奖位置
    init: function (id) {
        if ($("#" + id).find(".prize").length > 0) {
            $luck = $("#" + id);
            $units = $luck.find(".prize");
            this.obj = $luck;
            this.count = $units.length;
            $luck.find(".jp-" + this.index).addClass("active");
        }
    },
    roll: function () {
        var index = this.index;
        var count = this.count;
        var luck = this.obj;
        $(luck)
            .find(".jp-" + index)
            .removeClass("active");
        index += 1;
        if (index > count - 1) index = 0;
        $(luck)
            .find(".jp-" + index)
            .addClass("active");
        this.index = index;
        return false;
    },
    stop: function (index) {
        this.prize = index;
        return false;
    },
};
```

### 时间、转速、中奖下标控制

```javascript title="代码示例"
/* 时间、速度、中奖编号控制 */
function roll() {
    luck.times += 1;
    luck.roll();
    if (luck.times > luck.cycle + 10 && luck.prize == luck.index) {
        clearTimeout(luck.timer);
        luck.prize = -1;
        luck.times = 0;
        click = false;
    } else {
        if (luck.times < luck.cycle) {
            luck.speed -= 20;
        } else if (luck.times == luck.cycle) {
            // 奖品位置下标 全局变量prizeObj对象为中奖信息
            if (prizeObj.pIndex != "") luck.prize = prizeObj.pIndex;
        } else {
            if (
                luck.times > luck.cycle + 10 &&
                ((luck.prize == 0 && luck.index == 7) ||
                    luck.prize == luck.index + 1)
            ) {
                luck.speed += 110;
            } else {
                luck.speed += 20;
            }
        }
        if (luck.speed < 40) luck.speed = 40;
        luck.timer = setTimeout(roll, luck.speed);
    }
    return false;
}
```

### 加载抽奖动画

```javascript title="代码示例"
luck.init("prizeBox");
/* 点击抽奖 */
$("#Btn").click(function () {
    if (click) {
        return false;
    } else {
        $.ajax({
            async: false,
            url: "url",
            type: "post",
            data: {},
            dataType: "json",
            success: function (res) {
                if (res.code) {
                    /* 寻找商品下标 */
                    // 寻找中奖商品下标代码...

                    /* 动画 */
                    // 初始转速
                    luck.speed = 100;
                    // 触发动画
                    roll();
                    // 激活点击事件
                    click = true;
                    // 延时动画
                    setTimeout(function () {
                        $("#mask").fadeIn();
                    }, 3600);
                    return false;
                } else {
                    alert(res.message);
                }
            },
        });
        return false;
    }
});
```

### 中奖奖品位置的判断「回显到九宫格上」

```javascript title="代码示例"
function findPirzeIndex(data, goodId) {
    for (let j = 0, len = data.length; j < len; j++) {
        if (data[j].goodId == goodId) {
            switch (j) {
                case 0:
                    prizeObj.pIndex = 0;
                    break;
                case 3: // 3->7
                    prizeObj.pIndex = 7;
                    break;
                case 4: //
                    prizeObj.pIndex = 4;
                    break;
                case 5: // 5->3
                    prizeObj.pIndex = 3;
                    break;
                case 7: // 7->5
                    prizeObj.pIndex = 5;
                    break;
                default:
                    prizeObj.pIndex = j;
            }
        }
    }
}
```

:::info 总结
通过该方法来查找中奖奖品的位置；查找的元素的下标为该元素在其数组对象中的位置下标，此时对比图 1 和图 2 两个图表的位置信息，就可以确定中奖奖品所在图 1 表盘的具体位置。
:::