公司小程序完成后，产品突然需要增加一个新功能增项，结果其实就是一个购物车类似的功能
1、首先需要获取后台的数据
data: {open:false,animation_box:false,animationData:{}, //判断弹出上下滑动的inputOpen:false, //控制修改金额的弹窗id:'' ,//服务idservice:'' ,//服务数据charging_standard:'' ,//推送增项数据chooseId:'' ,//判断是否选中推送增项 和id相等则选中addService:[],//自定义增项数据selectService:[],//选中的增项inputPrice:'',//输入金额editPriceIndex:'',//编辑价格索引chooseAddService:[],//数量TotalPrice:'0',//总金额manageOpen:false, //显示是否展示删除选择的增项allselect:false,//判断全选choseIndex:'-1',//判断是否有选择删除的增项project:'', //自定义增项带过来的数据difference_id:''//增项记录id},//添加增项页面数据 这是自己的封装接口differenceData:function(){var that =this;let data={ //数据uid:wx.getStorageSync('uid'),order_id:that.data.id,}requestAjax.requestAjax('接口',data,'正在加载',function(res){var listItem = res.data.charging_standard; //返回的数组对象listItem.forEach((item)=>{ //y由于后台没有返回check值 所以自己添加了一个isSelected 为了判断选择和不选中false 不选中item.isSelected = false; item.number = "1"; //数量item.editPrice = item.price; //自己定义的价格 })that.setData({charging_standard:listItem //赋值给需要展示的数据数组})},function(){})},2、第二步 由于我们有推送数据，需要在数据里面选择在添加新的数组中去，所以需要判断是否有选中，把选中的服务添加到需要展示的数据中去，如果里面存在了，就不能再添加了，没有处理数量增加的，自己处理是去重
//选择推送服务chooseService:function(e){var that = this;var index = e.currentTarget.dataset.index; // 选中的索引var listItem = that.data.charging_standard; //推送增项数据var selectService = that.data.selectService; //已选择的商品数组var item = listItem[index];item.isSelected = !item.isSelected;that.setData({charging_standard:listItem,});if (listItem[index].isSelected){ //如果选中了, 就放到一选择的商品数组里for (var i = 0; i < listItem.length; i++) {if (listItem[i] == listItem[index]) {selectService.push(listItem[index])}}}else{ //取消选中就从已选择的商品数组里移除for (var i = 0; i < selectService.length; i++) {if(selectService[i].id == listItem[index].id){selectService.splice(i,1)}}}that.setData({selectService: selectService,});},//确认服务confirmAaditions:function(){let that = this;//需要判断选中的selectService里面是否已经存在了商品 如果存在则不再加入 如果不存在则加入进去//合并选中和已经展示的两个增项数组 去重let selectService = that.data.selectService;//页面推送总选中的增项数据let addService = that.data.addService; //展示中的增项数据addService=addService.concat(selectService) //合并两个数组that.unique(addService); //展示数组中去重},//去重数组unique:function (arr) {var that = this;if (!Array.isArray(arr)) {console.log('type error!')return}let res = []for (let i = 0; i < arr.length; i++) {if (res.indexOf(arr[i]) === -1) { //-1则没选中res.push(arr[i])}}res.forEach((item)=>{item.isSelected = false; //把选中的服务全部状态重置为false})that.setData({addService:res,//把页面推送数据添加到自定义增项数据里面open:false,});that.additionsTotalPrice(); //计算总价},第三、数量加减，总金额变化
//数量加addTap:function(e){var that = thisvar addService = that.data.addService;var index = e.currentTarget.dataset.index;var number = addService[index].number;number++;addService[index].number = number;that.setData({addService: addService,});that.additionsTotalPrice();},
//数量减reduceTap: function (e) {var that=this;var addService = that.data.addService;var index = e.currentTarget.dataset.index;var number = addService[index].number;if (number >1) {number--;addService[index].number = number;} else{addService[index].number = 1;};that.setData({addService: addService,});that.additionsTotalPrice();},
//增项总价格additionsTotalPrice:function(){let that = this;let TotalPrice = 0;for (var i = 0; i < this.data.addService.length; i++) {TotalPrice += that.data.addService[i].number * that.data.addService[i].editPrice};that.setData({TotalPrice: TotalPrice.toFixed(2)})},第四 删除想要删除的服务 单选和多选
// 全选select_all:function(){let that = this;that.setData({allselect: !that.data.allselect})if (that.data.allselect){let arr = that.data.addService;let arr2 = [];for (let i = 0; i < arr.length; i++) {if (arr[i].isSelected == true) {arr2.push(arr[i]);}else{arr[i].isSelected = true;arr2.push(arr[i]);}}that.setData({addService: arr2,chooseAddService:arr2,choseIndex:'0'})}},// 取消全选select_none:function(){let that = this;that.setData({allselect: !that.data.allselect})let arr = that.data.addService;let arr2 = [];for (let i = 0; i < arr.length; i++) {arr[i].isSelected = false;arr2.push(arr[i]);}that.setData({addService: arr2,chooseAddService:[],choseIndex:'-1'})},// 删除deleteServiceTap:function(){/*删除选中的服务，在现有的服务中删除选中的，把剩下的服务重新赋给需要展示的数组*/let that = this;let arr = that.data.addService; //原数组let choseIndex = that.data.choseIndex;let arr2 = []; //存放没有选中的服务if(choseIndex >= 0){wx.showModal({title:"确认删除所选增项?",success: (res) => {if (res.confirm) {for(let i=0;i<arr.length;i++){if (arr[i].isSelected == false){arr2.push(arr[i]);}};if(arr2 ==''){that.data.allselect = false; //全选为取消};that.setData({addService:arr2,chooseAddService:[],manageOpen:false,allselect:that.data.allselect,choseIndex:'-1'})that.additionsTotalPrice(); //计算总价}else if (res.cancel) {}}});}else{wx.showToast({title:"请选择要删除的增项服务",icon:"none"})}},