wx.requestPayment({

    'timeStamp': data.timeStamp,

    'nonceStr': data.nonceStr,

    'package': data.package,

    'signType': data.signType,

    'paySign': data.paySign,

    success(res) {

        if (res.errMsg == "requestPayment:ok"){

            console.log('成功');

        }

        console.log(res)

    },

    fail(res) {

        console.log('失败');

        console.log(res);

    }

})

手机上实测的时候点击立即支付有几率直接进入 fail 回调，然后小程序进入后台，调起微信聊天界面，然后支付界面