Mysql 颤振如何隐藏我的qr和点击生成代码后，它会出现，并保存在我的sql

您好，我想在点击生成的二维码按钮后显示我的二维码，并将其保存到我的mysql中

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('QR Code Generator'),
        actions: <Widget>[],
      ),
      body: Container(
        padding: EdgeInsets.all(20.0),
        child: Column(
          children: <Widget>[
            Text(
              "New QR Link Generator",
              style: TextStyle(fontSize: 20.0),
            ),
            TextField(
              controller: qrdataFeed,
              decoration: InputDecoration(
                hintText: "Input your link or data",
              ),
            ),
            Padding(
              padding: EdgeInsets.fromLTRB(40, 20, 40, 0),
              child: FlatButton(
                padding: EdgeInsets.all(15.0),
                onPressed: () async {
                  if (qrdataFeed.text.isEmpty) {

这是我的二维码显示，我希望在单击生成码后显示

  Container(
              height: 200,
              child: QrImage(
                //plce where the QR Image will be shown
                data: qrData,
              ),
            ),
          ],
        ),
      ),
    );
  }

  final qrdataFeed = TextEditingController();
}

  Container(
              height: 200,
              child: QrImage(
                //plce where the QR Image will be shown
                data: qrData,
              ),
            ),
          ],
        ),
      ),
    );
  }

  final qrdataFeed = TextEditingController();
}