https://api.weixin.qq.com/cgi-bin/qrcode/create?access_token=ACCESS_TOKEN"

调用以上接口生成的二维码url，使用drawQrcode显示的二维码。

drawQrcode({

                    canvas: canvas,

                    canvasId: 'myQrcode',

                    width: 200,

                    padding: 0,

                    background: '#ffffff',

                    foreground: '#000000',

                    text: url,

                }).then((res)=>{

                  wx.hideLoading()

                })

再扫码时显示