How to display an alert message if there is no data flutter - flutter

Question

I am doing a query about the data from a mysql database and they are displayed in a list.
My problem is if there is no data in the database. I would like to display an alert message stating that or display a text to warn that there is no available data.
This is the code page that I use to display the data:
void main() {
runApp(Your()
);
}
class Your extends StatefulWidget {
#override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<Your> {
MyPreferences _myPreferences = MyPreferences();
String apiURL;
var id;
List<Flowerdata> _flowersDataForTheListView = List<Flowerdata>();
Future<List<Flowerdata>> fetchNotes() async {
id=_myPreferences.id;
final String url = 'https://=============/All.php?id=' + id.toString();
var response = await http.get(url);
var flowers = List<Flowerdata>();
if (response.statusCode == 200) {
var flowersJsonData = json.decode(response.body);
for (var flower in flowersJsonData) {
flowers.add(Flowerdata.fromJson(flower));
}
}
else{
}
return flowers;
}
#override
void initState() {
fetchNotes();
super.initState();
}
#override
Widget build(BuildContext context) {
return ListView.builder(
itemBuilder: (context, index) {
return _listItem(index);
},
);
}
_listItem(index) {
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Row(
children: [
Flexible(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text( _flowersDataForTheListView[index].Name,style: TextStyle(fontSize: 17)),
SizedBox(height: 5.0,),
],
),
),
],
),
],
);
}
}
PHP contact page:
<?php
include 'connt.php';
$id=$_GET['id'];
$sql = "SELECT * FROM user WHERE id=? ORDER BY id DESC";
$stmt = $con->prepare($sql);
$stmt->bind_param("s",$id);
$stmt->execute();
$result = $stmt->get_result();
//$result = $con->query($sql);
if ($result->num_rows >0) {
while($row[] = $result->fetch_assoc()) {
$item = $row;
$json = json_encode($item, JSON_NUMERIC_CHECK);
}
} else {
echo "No";
}
echo $json;
$con->close();
?>
How can I do this if someone knows please help me.

Answer 1

You don't seem to be using MaterialApp in your flutter code, but if you use it, Scaffold widget has a method called showSnackbar where you can display a message that pops up at the bottom of the page.
Here is a sample code for showSnackbar:
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
home: HomePage(),
);
}
}
class HomePage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
body: MyList(),
);
}
}
class MyList extends StatefulWidget {
#override
_MyListState createState() => _MyListState();
}
class _MyListState extends State<MyList> {
#override
Widget build(BuildContext context) {
return Container();
}
#override
void initState() {
fetchNotes();
super.initState();
}
Future<void> fetchNotes() async {
// Here, you actually fetch the data from API
await Future.delayed(Duration(seconds: 3));
final flowers = [];
if (flowers.isEmpty) {
Scaffold.of(context).showSnackBar(
SnackBar(
content: Text('Data is empty'),
),
);
}
}
}