QRCode Generator

Question

In my flutter application I wanted to generate QR code that have the current time and user ID as data.Whenever I click on the button new QR code should be generated based on the time. This is my code for my qr

QrImage(
   data: tdata + userId,
   size: 250,
),

this is the code for my button

Button(
  onPressed: () {
  },
  label: const Text(
    'Generate',
  ),
),

Answer 1

I have used this package https://pub.dev/packages/qr_flutter

This is the demo of what you are looking for .

import 'package:qr_flutter/qr_flutter.dart';

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(home: QRGenerator());
  }
}

class QRGenerator extends StatefulWidget {
  const QRGenerator({Key? key}) : super(key: key);

  @override
  State<QRGenerator> createState() => _QRGeneratorState();
}

class _QRGeneratorState extends State<QRGenerator> {
  String userId = "userIdHere";

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            QrImage(
              data: "$userId ${DateTime.now()}",
              version: QrVersions.auto,
              size: 200.0,
            ),
            const SizedBox(
              height: 20,
            ),
            MaterialButton(
              onPressed: () {
                setState(() {});
              },
              child: const Text("Generate QR Code"),
              color: Colors.blue,
            )
          ],
        ),
      ),
    );
  }
}

Set the state when the button is clicked.. it will fetch the current time and add the user id to it and generate a new QR code.

Edit Create an int

int maxAttempt = 10;

On each button tap decrease this value

maxAttempt--;
setState((){});

Now on button click setState only if maxAttempt > 0 or you can also add condition in widget

(maxAttempt> 0) ? QrImage(): Text("max attempts reached")