微信小程序App中的值

微信小程序App中的值

detail.js中点击加入购物车

  onAddCart(){
    // 3.1获取商品对象
    const obj = {}
    obj.iid = this.data.iid
    obj.imageURL = this.data.topImages[0]
    obj.title = this.data.baseInfo.title
    obj.desc = this.data.baseInfo.desc
    obj.price = this.data.baseInfo.realPrice

    app.addToCart(obj)
  }

app.js存入全局变量cartList数组

App({
  globalData: {
    cartList: []
  },
  // 1.加入购物车操作
  addToCart(obj){
    const oldInfo = this.globalData.cartList.find( item => item.iid === obj.iid )
    if(oldInfo){
      oldInfo.count += 1
    }else{
      obj.count = 1
      obj.checked = true
      this.globalData.cartList.push(obj)
    }
  }
})

cart.js里面

const app = getApp()
Page({
  data: {
    cartList: [],
    isSelectAll: true,
    totalPrice: 0,
    totalCounter: 0
  }, 
  // 方法1、统计totalPrice和totalCount
  changeData() {
    let counter = 0
    let totalPrice = 0
    for(let item of this.data.cartList){
      if(item.checked){
        counter++
        totalPrice += item.price * item.count
      }
    }
    this.setData({
      totalCounter: counter,
      totalPrice: totalPrice
    })
  },
  onLoad: function(options) {
    // 1.第一次加载数据
    this.setData({
      cartList: app.globalData.cartList
    })
    // 2.cart-list-item里面check-icon发生改变
    app.changeGoodsState = (index,goods) => {
      // 1.修改某一项
      this.setData({
        [`cartList[${index}]`]: goods
      })
      // 2.修改bottom-bar里面的值
      const selectAll = !this.data.cartList.find(item => !item.checked)
      this.setData({
        isSelectAll: selectAll
      })
      this.changeData()
    }
  },
   // 1.进入页面
  onShow: function() {
  	// 1.1读取数据
  	this.changeData()
    // 1.2设置标题
    wx.setNavigationBarTitle({
      title: `购物车(${this.data.cartList.length})`,
    })
  },
  // 点击全选
  onSelectAll(){
    if(this.data.isSelectAll){//true全部选中
      this.data.cartList.forEach(item => {
        item.checked = false
      })
      this.setData({
        cartList: this.data.cartList,
        isSelectAll: false
      })
    }else{//某些没有选中
      this.data.cartList.forEach(item => item.checked = true)
      this.setData({
        cartList: this.data.cartList,
        isSelectAll: true
      })
    }
  }
})

cart-list-item.js

const app = getApp()

Component({
  methods: {
    onCheckClick(e){
      // 1.查找到对应的商品
      const goods = app.globalData.cartList.find(item => item.iid == this.properties.goods.iid)
      goods.checked = !goods.checked
      // 2.获取当前商品的index
      const index = e.currentTarget.dataset.index
      // 3.回调(重点)
      app.changeGoodsState(index,goods)
    }
  }
})