I am using the dB meter app to record noise and show it in decibels with periodic intervals. And I am printing decibels for every second. The app is working fine when active but when I press square button on android (That is pause the app) the decibel reading print -Infinity and the same thig happening when I click on circle button on android (that is inactive mode of the app). The original app git hub source - noise meter app source code.
And what I added to make automatic start and stop is this
Timer? _iStop;
Timer? _isStart;
@override
void initState() {
super.initState();
WidgetsBinding.instance!.addObserver(this);
_noiseMeter = NoiseMeter(onError);
_iStop = Timer.periodic(Duration(seconds: 20), (timer){
setState(() {
stop();
});
});
_isStart = Timer.periodic(Duration(seconds: 40), (timer){
setState(() {
start();
});
});
}
The app starting and stoping with regular time intervals with above mentioned time in the code. but the problem is when I pause or minimize the it is printing -Infinity as decibel reading.
I tried: didChangeAppLifecycleState method but this is to run or pause the app in the background. anyway our app is running in the background. Only thing is that it is showing -Infinity decibel when paused or minimized. Thanks in advance
main.dart
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'app.dart';
ThemeMode appTheme = ThemeMode.system; //dark / light
void main() => runApp(MyApp());
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
@override
Widget build(BuildContext context) {
return MaterialApp(
// debugShowCheckedModeBanner: false,
title: 'db Meter',
home: NoiseApp(),
darkTheme: ThemeData.dark().copyWith(
textTheme: ThemeData.dark().textTheme.apply(
fontFamily: GoogleFonts.comfortaa().fontFamily,
),
primaryTextTheme: ThemeData.dark().textTheme.apply(
fontFamily: GoogleFonts.comfortaa().fontFamily,
),
accentTextTheme: ThemeData.dark().textTheme.apply(
fontFamily: GoogleFonts.comfortaa().fontFamily,
),
),
theme: ThemeData(
fontFamily: GoogleFonts.comfortaa().fontFamily,
),
themeMode: appTheme,
);
}
}
app.dart
// https://github.com/syncfusion/flutter-examples/blob/master/lib/samples/chart/dynamic_updates/live_update/real_time_line_chart.dart
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:noise_meter/noise_meter.dart';
import 'package:syncfusion_flutter_charts/charts.dart';
import 'package:url_launcher/url_launcher.dart';
class NoiseApp extends StatefulWidget {
@override
_NoiseAppState createState() => _NoiseAppState();
}
class _NoiseAppState extends State<NoiseApp> {
bool _isRecording = false;
// ignore: cancel_subscriptions
StreamSubscription<NoiseReading>? _noiseSubscription;
late NoiseMeter _noiseMeter;
double? maxDB;
double? meanDB;
List<_ChartData> chartData = <_ChartData>[];
// ChartSeriesController? _chartSeriesController;
late int previousMillis;
Timer? _iStop;
Timer? _isStart;
@override
void initState() {
super.initState();
_noiseMeter = NoiseMeter(onError);
_iStop = Timer.periodic(Duration(seconds: 20), (timer){
setState(() {
stop();
});
});
_isStart = Timer.periodic(Duration(seconds: 40), (timer){
setState(() {
start();
});
});
}
void onData(NoiseReading noiseReading) {
this.setState(() {
if (!this._isRecording) this._isRecording = true;
});
maxDB = noiseReading.maxDecibel;
meanDB = noiseReading.meanDecibel;
chartData.add(
_ChartData(
maxDB,
meanDB,
((DateTime.now().millisecondsSinceEpoch - previousMillis) / 1000)
.toDouble(),
),
);
print("max db $maxDB");
}
void onError(Object e) {
print(e.toString());
_isRecording = false;
}
void start() async {
previousMillis = DateTime.now().millisecondsSinceEpoch;
try {
_noiseSubscription = _noiseMeter.noiseStream.listen(onData);
} catch (e) {
print(e);
}
}
void stop() async {
try {
_noiseSubscription!.cancel();
_noiseSubscription = null;
this.setState(() => this._isRecording = false);
} catch (e) {
print('stopRecorder error: $e');
}
previousMillis = 0;
chartData.clear();
}
void copyValue(
bool theme,
) {
Clipboard.setData(
ClipboardData(
text: 'It\'s about ${maxDB!.toStringAsFixed(1)}dB loudness'),
).then((_) {
ScaffoldMessenger.of(context).showSnackBar(
SnackBar(
behavior: SnackBarBehavior.floating,
duration: Duration(milliseconds: 2500),
content: Row(
children: [
Icon(
Icons.check,
size: 14,
color: theme ? Colors.white70 : Colors.black,
),
SizedBox(width: 10),
Text('Copied')
],
),
),
);
});
}
openGithub() async {
const url = 'https://github.com/iqfareez/noise_meter_flutter';
try {
await launch(url);
} catch (e) {
ScaffoldMessenger.of(context).showSnackBar(SnackBar(
content: Text('Could not launch $url'),
backgroundColor: Colors.red,
));
}
}
@override
Widget build(BuildContext context) {
bool _isDark = Theme.of(context).brightness == Brightness.light;
if (chartData.length >= 25) {
chartData.removeAt(0);
}
return Scaffold(
appBar: AppBar(
backgroundColor: _isDark ? Colors.green : Colors.green.shade800,
title: Text('dB Sound Meter'),
actions: [
IconButton(
tooltip: 'Source code on GitHub',
icon: Icon(Icons.code_outlined),
onPressed: openGithub),
IconButton(
tooltip: 'Copy value to clipboard',
icon: Icon(Icons.copy),
onPressed: maxDB != null ? () => copyValue(_isDark) : null,
)
],
),
floatingActionButtonLocation: FloatingActionButtonLocation.centerFloat,
floatingActionButton: FloatingActionButton.extended(
label: Text(_isRecording ? 'Stop' : 'Start'),
onPressed: _isRecording ? stop : start,
icon: !_isRecording ? Icon(Icons.circle) : null,
backgroundColor: _isRecording ? Colors.red : Colors.green,
),
body: Container(
child: Column(
children: [
Expanded(
flex: 2,
child: Center(
child: Text(
maxDB != null ? maxDB!.toStringAsFixed(2) : 'Press start',
style: GoogleFonts.exo2(fontSize: 76),
),
),
),
Text(
meanDB != null
? 'Mean: ${meanDB!.toStringAsFixed(2)}'
: 'Awaiting data',
style: TextStyle(fontWeight: FontWeight.w300, fontSize: 14),
),
Expanded(
child: SfCartesianChart(
series: <LineSeries<_ChartData, double>>[
LineSeries<_ChartData, double>(
dataSource: chartData,
xAxisName: 'Time',
yAxisName: 'dB',
name: 'dB values over time',
xValueMapper: (_ChartData value, _) => value.frames,
yValueMapper: (_ChartData value, _) => value.maxDB,
animationDuration: 0),
],
),
),
SizedBox(
height: 68,
),
],
),
),
);
}
}
class _ChartData {
final double? maxDB;
final double? meanDB;
final double frames;
_ChartData(this.maxDB, this.meanDB, this.frames);
}
pubspec.yaml
name: noise_meter_flutter
description: Sound meter
publish_to: "none"
version: 1.1.0-f+3
environment:
sdk: ">=2.12.0 <3.0.0"
dependencies:
flutter:
sdk: flutter
# cupertino_icons: ^1.0.0
noise_meter: ^3.0.1
syncfusion_flutter_charts: ^19.1.67
url_launcher: ^6.0.6
google_fonts: ^2.1.0
dev_dependencies:
flutter_test:
sdk: flutter
flutter:
uses-material-design: true
when screen visible:
Whe the app is paused or minimized:
