i try to make permission handler for flutter

Question

I am building a music player application. I want to ask the user to allow access to storage when the application is opened. I used this method and it works properly during testing, but when I get output from the application and upload it to the Google Store, it does not allow access.

Where is my problem?

 denied() {
return showDialog(
    barrierColor: Colors.white.withOpacity(0.5),
    context: context,
    builder: (context) {
      return AlertDialog(
          backgroundColor: Colors.black,
          title: Text(
            'Allow Permission',
            style: TextStyle(color: Colors.white),
          ),
          content: Container(
            height: MediaQuery.of(context).size.height * 0.2,
            child: Column(
              children: [
                Text(
                  'Music Player needs access to audio files to play music.',
                  style: TextStyle(color: Colors.white),
                ),
                Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    TextButton(
                        onPressed: () {
                          _promasionrequest();
                          Navigator.pop(context);
                        },
                        child: Text(
                          'Allow',
                          style: TextStyle(
                              fontWeight: FontWeight.normal,
                              fontStyle: FontStyle.italic,
                              color: Colors.blue),
                        )),
                    TextButton(
                        onPressed: () {
                          exit(0);
                        },
                        child: Text(
                          'Deny',
                          style: TextStyle(
                              fontWeight: FontWeight.normal,
                              fontStyle: FontStyle.italic,
                              color: Colors.blue),
                        ))
                  ],
                )
              ],
            ),
          ));
    });
}
 _promasionrequest() async {
Permission.storage.request();
var status = await Permission.storage.status;
setState(() {
  permissionStatus = status;
});
setState(() {
  switch (status) {
    case PermissionStatus.granted:
      setState(() {
        acsept = true;
      });
      getSongs();
      break;
    case PermissionStatus.denied:
      denied();
      testText = 'denied';
      break;
    case PermissionStatus.limited:
      denied();
      testText = 'limited';
      break;
    case PermissionStatus.restricted:
      denied();
      testText = 'restricted';
      break;
    case PermissionStatus.permanentlyDenied:
      denied();
      testText = 'permanentlyDenied';
      break;
    default:
    // getSongs();
  }
});
}