var app = getApp();
    Page({
        data: {},
        onLoad: function (options) {
            // 页面初始化 options为页面跳转所带来的参数
            var that = this
            //登陆获取code
            wx.login({
                success: function (res) {
                    console.log(res.code)
                    //获取openid
                    that.getOpenId(res.code)
                }
            });
        },
        getOpenId: function (code) {
            var that = this;
            wx.request({
                url: "https://api.weixin.qq.com/sns/jscode2session?appid=小程序appid&secret=小程序应用密钥&js_code=" + code + "&grant_type=authorization_code",
                data: {},
                method: 'GET',
                success: function (res) {
                    that.generateOrder(res.data.openid)
                },
                fail: function () {
                    // fail
                },
                complete: function () {
                    // complete
                }
            })
        },
        /**生成商户订单 */
        generateOrder: function (openid) {
            var that = this
            //统一支付
            wx.request({
                url: '后台路径',
                method: 'GET',
                data: {
                    gfee: '商品价钱',
                    gname: '商品名称',
                    openId:openid
                    （商品价钱和商品名称根据自身需要是否传值,openid为必传）
                },
                success: function (res) {
                    var pay = res.data
                    //发起支付
                    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(默认为1) 页面
                        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
                }
            })
        }
    })