微信小程序实现加入购物车滑动轨迹

.good_box {
 width: 80rpx;
 height: 80rpx;
 position: fixed;
 border-radius: 50%;
 overflow: hidden;
 left: 50%;
 : 50%;
 z-index: 99;
}

<view class="iconfont icongouwuche remend_item_shopcar" bindtap="touchOnGoods"></view>
<view class="good_box" hidden="{{hide_good_box}}" style="left: {{bus_x}}px; : {{bus_y}}px;">
 <image class="image" src="/img/luntai2.png"></image>
</view>

//app.js
App({
 onLaunch: function() {
 //调用API从本地缓存中获取数据
 // var logs = wx.getStorageSync('logs') || []
 // logs.unshift(Date.now())
 // wx.setStorageSync('logs', logs)
 this.screenSize();
 },
 getUserInfo: function(cb) {
 var that = this
 if (this.globalData.userInfo) {
  typeof cb == "function" && cb(this.globalData.userInfo)
 } else {
  //调用登录接口
  wx.login({
  suess: function() {
   wx.getUserInfo({
   suess: function(res) {
    that.globalData.userInfo = res.userInfo
    typeof cb == "function" && cb(that.globalData.userInfo)
   }
   })
  }
  })
 }
 },
 //获取屏幕[宽、高]

 screenSize: function() {
 var that = this;
 wx.getSystemInfo({
  suess: function(res) {
  that.globalData.ww = res.windowWidth;
  that.globalData.hh = res.windowHeight;
  }

 })

 },

 /
 
   @param sx 起始点x坐标 
   @param sy 起始点y坐标 
   @param cx 控制点x坐标 
   @param cy 控制点y坐标 
   @param ex 结束点x坐标 
   @param ey 结束点y坐标 
   @param part 将起始点到控制点的线段分成的份数，数值越高，计算出的曲线越精确 
   @return 贝塞尔曲线坐标
 
  /

 bezier: function(points, part) {

 let sx = points[0]['x'];
 let sy = points[0]['y'];
 let cx = points[1]['x'];
 let cy = points[1]['y'];
 let ex = points[2]['x'];
 let ey = points[2]['y'];
 var bezier_points = [];

 // 起始点到控制点的x和y每次的增量
 var changeX1 = (cx - sx) / part;
 var changeY1 = (cy - sy) / part;

 // 控制点到结束点的x和y每次的增量
 var changeX2 = (ex - cx) / part;
 var changeY2 = (ey - cy) / part;

 //循环计算
 for (var i = 0; i <= part; i++) {
  // 计算两个动点的坐标

  var qx1 = sx + changeX1  i;
  var qy1 = sy + changeY1  i;
  var qx2 = cx + changeX2  i;
  var qy2 = cy + changeY2  i;

  // 计算得到此时的一个贝塞尔曲线上的点
  var lastX = qx1 + (qx2 - qx1)  i / part;
  var lastY = qy1 + (qy2 - qy1)  i / part;

  // 保存点坐标
  var point = {};
  point['x'] = lastX;
  point['y'] = lastY;
  bezier_points.push(point);

 }

 //console.log(bezier_points)
 return {
  'bezier_points': bezier_points

 };

 },
 globalData: {
 ww:'',
 hh:''
 }
})

//index.js
//获取应用实例
const app = getApp()

Page({
 data: {
 indicatorDots: true,
 vertical: false,
 aulay: false,
 interval: 2000,
 duration: 500,
 hide_good_box: true,
 },
 onLoad: function () {
 this.busPos = {};

 this.busPos['x'] = app.globalData.ww / 1.4; //1.4修改轨迹结束时x轴的位置，2是在正中心

 this.busPos['y'] = app.globalData.hh - 10;

 console.log('购物车坐标', this.busPos)
 },
 onShow(){
 app.editTabBar(); //显示自定义的底部导航
 },
 tosearchpage(e){
 wx.navigateTo({
  url: '',
 })
 },
 touchOnGoods: function (e) {
 // 如果good_box正在运动
 if (!this.data.hide_good_box) return;
 this.finger = {};
 var Point = {};
 this.finger['x'] = e.touches["0"].clientX;
 this.finger['y'] = e.touches["0"].clientY;

 if (this.finger['y'] < this.busPos['y']) {
  Point['y'] = this.finger['y'] - 150;
 } else {
  Point['y'] = this.busPos['y'] - 150;

 }
 Point['x'] = Math.abs(this.finger['x'] - this.busPos['x']) / 2;
 if (this.finger['x'] > this.busPos['x']) {
  Point['x'] = (this.finger['x'] - this.busPos['x']) / 2 + this.busPos['x'];
 } else {
  Point['x'] = (this.busPos['x'] - this.finger['x']) / 2 + this.finger['x'];

 }

 this.linePos = app.bezier([this.finger, Point, this.busPos], 20);
 this.startAnimation();

 },

 startAnimation: function () {
 var index = 0,
  that = this,
  bezier_points = that.linePos['bezier_points'],
  len = bezier_points.length - 1;
 this.setData({

  hide_good_box: false,
  bus_x: that.finger['x'],
  bus_y: that.finger['y']

 })

 this.timer = setInterval(function () {
  index++;
  that.setData({
  bus_x: bezier_points[index]['x'],
  bus_y: bezier_points[index]['y']
  })

  if (index >= len) {
  clearInterval(that.timer);
  that.setData({
   hide_good_box: true,

  })

  }

 }, 15);

 },
})