Flutter fetch widget by status not working - flutter

Question

I wrote a code like this:
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_sms_inbox/flutter_sms_inbox.dart';
class Inbox extends StatefulWidget {
const Inbox({Key? key}) : super(key: key);
#override
State<Inbox> createState() => _InboxState();
}
SmsQuery query = new SmsQuery();
List<SmsMessage> AllMessages = [];
Timer? _timer;
class _InboxState extends State<Inbox> {
#override
void initState() {
GetAllMessages();
_timer = Timer.periodic(const Duration(seconds: 1), (Timer t) {
GetAllMessages();
print("refreshed");
print(AllMessages); // output: []
});
super.initState();
}
Future<void> GetAllMessages() async {
Future.delayed(Duration.zero, () async {
List<SmsMessage> messages = await query.querySms(
kinds: [SmsQueryKind.inbox],
count: 50,
);
setState(() {
AllMessages = messages;
});
});
}
#override
void dispose() {
_timer?.cancel();
super.dispose();
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: SingleChildScrollView(
physics: const BouncingScrollPhysics(),
child: Page(),
),
);
}
}
Widget Page() {
if (AllMessages == null) {
return Text("No message");
} else {
Column(
children: [
const SizedBox(height: 25),
Container(
child: Column(
children: AllMessages.map((msg) {
return Container(
child: Card(
child: ListTile(
leading: Text("${msg.body}"),
title: Text("${msg.address}"),
),
),
);
}
).toList(),
),
),
],
);
}
return SizedBox();
}
I'm trying to access and list SMS's on the phone. I save the SMS in the list called AllMessages. If there is no SMS, I want it to show a Text named No message but it doesn't.
It shows blank as in the picture:
Why could this be? How can I solve the problem? Thanks in advance for your help.