Generate multiple bar/qr codes

I am trying to create a QR/Bar code Generator app in which users are allowed to give the quantity(also some name printed below the bar code) they want to generate and save the generated code as a PDF. What is the best way to generate bulk QR/Bar codes in flutter?

With the below code I am able to generate one QR/Bar code

      children: [

          barColor: Colors.white,
          value: controller.text,
          //symbology: QRCode(),
          showValue: true,
          textSpacing: 15,
          textStyle: TextStyle(fontSize: 20,color:,
        SizedBox(height: 40),
          children: [
            Expanded(child: buildTextField(context)),
            const SizedBox(width: 12),
              backgroundColor: Theme.of(context).primaryColor,
              child: Icon(Icons.done, size: 30),
              onPressed: () {
                print("I am from on Pressed");
                Expanded(child: resultTextField(context,controller.text));

Any help is really appreciated.Thanks in advance