I am not able to display notfication popup on screen when app is open and screen is lock any solution

[amelioratesolutions]

FirebaseMessaging.onMessage.listen((RemoteMessage message) {
// viewShowRide == true;
if (message.data != null &&
message.data['title'] != null &&
message.data['body'] != null) {
var title = message.data['title'];
var body = message.data['body'];
print('Push Listen*');
print("SOCKET");
print(title.toString());
print(body.toString());
// Parse the message received
PushNotification _notificationInfo = PushNotification(
title: title,
body: body,
);

  showSimpleNotification(
    Text(_notificationInfo.title,
          style: Theme
              .of(context)
              .textTheme
              .headline3
              .copyWith(color: whiteColor)),

    subtitle: Text(
      _notificationInfo.body,
      style: Theme
          .of(context)
          .textTheme
          .headline2
          .copyWith(color: whiteColor),
    ),
    background: textLight,
    duration: Duration(seconds: 5),
  );
} else {

  // show popup when value is true

  setState(() {
    bookingArrive == true ? viewShowRide = true : false;
  });

  PushNotification _notificationInfo = PushNotification(
    title: message.notification?.title,
    body: message.notification?.body,
  );
  print('************Push Listen*************');
  if (_notificationInfo != null) {
    // For displaying the notification as an overlay
    showSimpleNotification(
      Text(_notificationInfo.title,
            style: Theme
                .of(context)
                .textTheme
                .headline3
                .copyWith(color: whiteColor)),

      subtitle: Text(
        _notificationInfo.body,
        style: Theme
            .of(context)
            .textTheme
            .headline2
            .copyWith(color: whiteColor),
      ),
      background: textLight,
      duration: Duration(seconds: 5),
    );
  }
}

});
This is condition for displaying widget

viewShowRide ? bottomRiderView() : Container(),

I am new to flutter plz give me solution to show popup if screen is lock and app is open in flutter