Alert dialog didnt invoke - url

Question

Content of this code is after a QR scan it need alert a dialog with confirm to redirect for that i use ShowDialog in the function it need a context of Widget so I used AlertDialog directly.
If i use ShowDialog in side the scaffold i didnt get the scanned data of Qr code. So what to do?
This is the code:
import 'package:appteq_solutions/dashboard.dart';
import 'package:flutter/material.dart';
import 'package:qr_code_scanner/qr_code_scanner.dart';
import 'package:url_launcher/url_launcher.dart';
class Scanner extends StatelessWidget {
Scanner({super.key});
final GlobalKey qrKey = GlobalKey(debugLabel: 'QR');
late QRViewController controller;
Future<Void> _onQRViewCreated(QRViewController controller) {
this.controller = controller;
controller.scannedDataStream.listen((scanData) async {
controller.pauseCamera();
print(scanData.code);
final uri = Uri.parse(scanData.code as String);
AlertDialog(
title: Text('Redirect To The Url'),
content: SingleChildScrollView(
child: ListView(),
),
actions: <Widget>[
ElevatedButton(
onPressed: () {},
child: Text('No'),
),
ElevatedButton(
child: const Text("Confirm"),
onPressed: () async {
if (await canLaunchUrl(uri)) {
await launchUrl(uri);
controller.resumeCamera();
}
},
),
]);
// }
});
return ;
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('QR Scanner'),
),
body: Stack(
children: [
Column(
children: <Widget>[
Expanded(
flex: 5,
child: Stack(
children: [
QRView(
key: qrKey,
onQRViewCreated: _onQRViewCreated,
),
Center(`your text`
child: Container(
width: 300,
height: 300,
decoration: BoxDecoration(
border: Border.all(
color: Colors.red,
width: 4,
),
borderRadius: BorderRadius.circular(12),
),
),
),
],
),
),
Expanded(
flex: 1,
child: GestureDetector(
onTap: () {
Navigator.of(context).pushReplacement(MaterialPageRoute(
builder: (BuildContext context) => Dashboard()));
},
child: Center(
child: Text(
' Press Here To Go DashBoard',
style:
TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
),
),
),
),
],
),
],
),
);
}
}
Help me use Alerdialog in function or to pass the data in dcaffold.