Vue实战—商品分类菜单数量提示（10）

如上所示，这篇我们将商品分类菜单显示数量的提示完善，是软件更加易于使用。

好先让我回顾一下上节课的内容，Goods组件，数量提示功能最终需要在Goods组件内显示。

<template>
  <div class="goods">
    <div class="menu-wrapper" ref="menuScroll">
      <ul>
        <!--专场-->
        <li class="menu-item" :class="{'current':currentIndex===0}" @click="selectMenu(0)">
          <p class="text">
            <img :src="container.tag_icon" v-if="container.tag_icon" class="icon">
            {{container.tag_name}}
          </p>
        </li>
        <li
          class="menu-item"
          v-for="(item,index) in goods"
          :class="{'current':currentIndex===index+1}"
          @click="selectMenu(index+1)"
        >
          <p class="text">
            <img :src="item.icon" v-if="item.icon" class="icon">
            {{item.name}}
          </p>
          <i class="num" v-show="calculateCount(item.spus)">{{calculateCount(item.spus)}}</i>//通过i标签展示数量
        </li>
      </ul>
    </div>
    <!-- 右侧商品列表 -->
    <div class="foods-wrapper" ref="foodScroll">
      <!--专场-->
      <ul>
        <li class="container-list food-list-hook">
          <div v-for="item in container.operation_source_list">
            <img :src="item.pic_url">
          </div>
        </li>
        <!-- 具体分类-->
        <li v-for="item in goods" class="food-list food-list-hook">
          <h3 class="title">{{item.name}}</h3>
          <!--具体商品列表-->
          <ul>
            <li v-for="food in item.spus" class="food-item">
                
              <div class="icon" :style="head_bg(food.picture)"></div>

              <div class="content">
                <h3 class="name">{{food.name}}</h3>
                <p class="desc" v-if="food.description">{{food.description}}</p>
                <div class="extra">
                  <span class="saled">{{food.month_saled_content}}</span>
                  <span class="praise">{{food.praise_content}}</span>
                </div>
                <img
                  class="product"
                  :src="food.product_label_picture"
                  v-show="food.product_label_picture"
                >
                <p class="price">
                  <span class="text">￥{{food.min_price}}</span>
                  <span class="unit">/{{food.unit}}</span>
                </p>
              </div>
              <div class="cartcontrol-wrapper">
                <Cartcontrol :food="food"></Cartcontrol>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>
    <Shopcart :poiInfo="poiInfo" :selectFoods="selectFoods"></Shopcart>
  </div>
</template>

<script>
import BScroll from "better-scroll";
import Shopcart from "components/Shopcart/Shopcart";
import Cartcontrol from "components/Cartcontrol/Cartcontrol";

export default {
  data() {
    return {
      container: {},
      goods: [],
      poiInfo: {},
      listHeight: [],
      menuScroll: {},
      foodScroll: {},
      scrollY: 0
    };
  },
  components: {
    BScroll,
    Shopcart,
    Cartcontrol

  },
  created() {
    this.$axios
      .get("api/goods")
      .then(response => {
        let json = response.data;
        if (json.code === 0) {
          // 重点
          this.container = json.data.container_operation_source;
          this.goods = json.data.food_spu_tags;
          console.log(this.goods)
          this.poiInfo = json.data.poi_info;
          this.$nextTick(function() {
            this.initScroll();
            // 左右联动
            // 右->左
            // 计算区间
            this.caculateHeight();
          });
        }
      })
      .catch(function(error) {
        // handle error
        console.log(error);
      });
  },
  computed: {
    // 根据右侧判断左侧index
    currentIndex() {
      for (let i = 0; i < this.listHeight.length; i++) {
        let start = this.listHeight[i];
        let end = this.listHeight[i + 1];
        if (this.scrollY >= start && this.scrollY < end) {
          return i;
        }
      }
      return 0;
    },
    selectFoods() {
      let foods = [];
         this.goods.forEach(good => {
          good.spus.forEach(food => {
            if (food.count > 0) {
              foods.push(food);
            }
          }); 
        });
      return foods;
    }
  },
  methods: {
    head_bg(imgName) {
      return "background-image: url(" + imgName + ");";
    },
    initScroll() {
      this.menuScroll = new BScroll(this.$refs.menuScroll, {
        click: true
      });
      this.foodScroll = new BScroll(this.$refs.foodScroll, {
        probeType: 3,
        click: true
      });
      this.foodScroll.on("scroll", pos => {
        this.scrollY = Math.abs(Math.round(pos.y));
      });
    },
    caculateHeight() {
      let foodList = this.$refs.foodScroll.getElementsByClassName(
        "food-list-hook"
      );
      let height = 0;
      this.listHeight.push(height);
      for (let i = 0; i < foodList.length; i++) {
        height += foodList[i].clientHeight;
        this.listHeight.push(height);
      }
      // [0, 215, 1343, 2425, 3483, 4330, 5823, 7237, 8022, 8788, 9443]
    },
    selectMenu(index) {
      // console.log(index);

      let foodlist = this.$refs.foodScroll.getElementsByClassName(
        "food-list-hook"
      );

      // 根据下标，滚动到相对应的元素
      let el = foodlist[index];
      // 滚动到对应元素的位置
      this.foodScroll.scrollToElement(el, 100);
    },
    calculateCount(spus) {
        console.log(spus)
      let count = 0;
      spus.forEach(food => {
        if (food.count > 0) {
          count += food.count;
        }
      });

      return count;
    },
  }
};
</script>

注意methods方法中的calculateCount函数实现计算个数，数量来自于增减组件内Cartcontrol。

    calculateCount(spus) {
        console.log(spus)
      let count = 0;
      spus.forEach(food => {
        if (food.count > 0) {
          count += food.count;
        }
      });

      return count;
    },

以上是spus数据

Cartcontrol组件控制商品增减

通过组件Cartcontrol接受了来自父组件的传值，并且我们在组件内添加商品的增减功能。

<template>
  <div class="cartcontrol">
    <transition name="move">
      <div class="cart-decrease" @click="decreaseCart" v-show="food.count">
        <span class="inner icon-remove_circle_outline"></span>
      </div>
    </transition>
    <div class="cart-count" v-show="food.count">{{food.count}}</div>
    <div class="cart-add icon-add_circle" @click="increaseCart">
      <i class="bg"></i>
    </div>
  </div>
</template>

<script>
import Vue from 'vue'
export default {
  props:{
    food:{
      type:Object
    }
  },
  methods:{
    decreaseCart(){
      this.food.count--;//this指向了vue实例
       
    },
    increaseCart(){
      if(!this.food.count){
        Vue.set(this.food,'count',1);
      }else{
        this.food.count++;
      }
    }
    
  }
};
</script>

完善购物车内的数量统计

<template>
  <div class="shopcart" :class="{'highligh':totalCount>0}">
    <div class="shopcart-wrapper">
      <div class="content-left">
        <div class="logo-wrapper" :class="{'highligh':totalCount>0}">
          <span class="icon-shopping_cart logo" :class="{'highligh':totalCount>0}"></span>
          <i class="num" v-show="totalCount">{{totalCount}}</i>
        </div>
        <div class="desc-wrapper">
          <p class="total-price" v-show="totalPrice">￥{{totalPrice}}</p>
          <p class="tip" :class="{'highligh':totalCount>0}">另需{{shipping_fee_tip}}</p>
        </div>
      </div>

      <div class="content-right" :class="{'highligh':totalCount>0}">{{payStr}}</div>
    </div>
  </div>
</template>

<script>
// 导入BScroll
import BScroll from "better-scroll";

export default {
  props: {
    min_price_tip: {
      type: String,
      default: ""
    },
    shipping_fee_tip: {
      type: String,
      default: ""
    },
    selectFoods: {
      type: Array,
      default() {
        return [
          /*  {
            min_price: 10,
            count: 3
          },
          {
            min_price: 7,
            count: 1
          } */
        ];
      }
    }
  },
  computed: {
    // 总个数
    totalCount() {
      let num = 0;
      this.selectFoods.forEach(food => {
        num += food.count;
      });

      return num;
    },
    // 总金额
    totalPrice() {
      let total = 0;
      this.selectFoods.forEach(food => {
        total += food.min_price * food.count;
      });

      return total;
    },
    // 结算按钮显示
    payStr() {
      if (this.totalCount > 0) {
        return "去结算";
      } else {
        return this.min_price_tip;
      }
    }
  },
  components: {
    BScroll
  }
};
</script>

现在商品分类菜单的数量提示就完成了。