var app = getApp();
 Page({
   data: {},
   onLoad: function (options) {
      // 頁面初始化 options為頁面跳轉所帶來的引數
     var that = this
      //登陸獲取code
      wx.login({
        success: function (res) {
         console.log(res.code)
         //獲取openid
         that.getOpenId(res.code)
       }
     });
   },
   getOpenId: function (code) {
     var that = this;
     wx.request({
       url: "https://api.weixin.qq.com/sns/jscode2session?appid=小程式appid&secret=小程式應用金鑰&js_code=" + code + "&grant_type=authorization_code",
       data: {},
       method: 'GET',
       success: function (res) {
         that.generateOrder(res.data.openid)
       },
       fail: function () {
         // fail
       },
       complete: function () {
         // complete
       }
     })
   },
   /**生成商戶訂單 */
   generateOrder: function (openid) {
     var that = this
     //統一支付
     wx.request({
       url: '後臺路徑',
       method: 'GET',
       data: {
         gfee: '商品價錢',
         gname: '商品名稱',
         openId:openid
         （商品價錢和商品名稱根據自身需要是否傳值,openid為必傳）
       },
       success: function (res) {
         var pay = res.data
         //發起支付
         var timeStamp = pay[0].timeStamp;
         var packages = pay[0].package;
         var paySign = pay[0].paySign;
         var nonceStr = pay[0].nonceStr;
         var param = { "timeStamp": timeStamp, "package": packages, "paySign": paySign, "signType": "MD5", "nonceStr": nonceStr };
         that.pay(param)
       },
     })
   },
  
   /* 支付  */
   pay: function (param) {
     console.log("支付")
     console.log(param)
     wx.requestPayment({
       timeStamp: param.timeStamp,
       nonceStr: param.nonceStr,
       package: param.package,
       signType: param.signType,
       paySign: param.paySign,
       success: function (res) {
         // success
         wx.navigateBack({
           delta: 1, // 回退前 delta(預設為1) 頁面
           success: function (res) {
             wx.showToast({
               title: '支付成功',
               icon: 'success',
               duration: 2000
             })
           },
           fail: function () {
             // fail
  
           },
           complete: function () {
            // complete
           }
         })
       },
       fail: function (res) {
         // fail
       },
       complete: function () {
         // complete
       }
     })
   }
 })