feat: comply with flutter's and dart's null safety (anarchuser#25)

Author: anarchuser

CHANGELOG.md

@@ -1,3 +1,7 @@
+### 0.5.3
+
+* Comply with [Null safety](https://flutter.dev/docs/null-safety)
+
 ### 0.5.2
 
 * Fixed permissions to record audio not being requested (solves [#19](https://github.com/anarchuser/mic_stream/issues/19))

example/lib/main.dart

@@ -28,22 +28,22 @@ class MicStreamExampleApp extends StatefulWidget {
 
 class _MicStreamExampleAppState extends State<MicStreamExampleApp>
     with SingleTickerProviderStateMixin, WidgetsBindingObserver {
-  Stream stream;
-  StreamSubscription listener;
-  List<int> currentSamples = [];
+  Stream? stream;
+  late StreamSubscription listener;
+  List<int>? currentSamples = [];
   List<int> visibleSamples = [];
-  int localMax;
-  int localMin;
+  int? localMax;
+  int? localMin;
 
 
   // Refreshes the Widget for every possible tick to force a rebuild of the sound wave
-  AnimationController controller;
+  late AnimationController controller;
 
   Color _iconColor = Colors.white;
   bool isRecording = false;
   bool memRecordingState = false;
-  bool isActive;
-  DateTime startTime;
+  late bool isActive;
+  DateTime? startTime;
 
   int page = 0;
   List state = ["SoundWavePage", "IntensityWavePage", "InformationPage"];
@@ -53,7 +53,7 @@ class _MicStreamExampleAppState extends State<MicStreamExampleApp>
   void initState() {
     print("Init application");
     super.initState();
-    WidgetsBinding.instance.addObserver(this);
+    WidgetsBinding.instance!.addObserver(this);
     setState(() {
       initPlatformState();
     });
@@ -80,8 +80,8 @@ class _MicStreamExampleAppState extends State<MicStreamExampleApp>
       !isRecording ? await _startListening() : _stopListening();
 
 
-  int bytesPerSample;
-  int samplesPerSecond;
+  late int bytesPerSample;
+  late int samplesPerSecond;
 
   Future<bool> _startListening() async {
     print("STARRT LISTENING");
@@ -98,8 +98,8 @@ class _MicStreamExampleAppState extends State<MicStreamExampleApp>
     // after invoking the method for the first time, though, these will be available;
     // It is not necessary to setup a listener first, the stream only needs to be returned first
     print("Start Listening to the microphone, sample rate is ${await MicStream.sampleRate}, bit depth is ${await MicStream.bitDepth}, bufferSize: ${await MicStream.bufferSize}");
-		bytesPerSample = (await MicStream.bitDepth / 8).toInt();
-    samplesPerSecond = (await MicStream.sampleRate).toInt();
+		bytesPerSample = ((await MicStream.bitDepth)! / 8).toInt();
+    samplesPerSecond = (await MicStream.sampleRate)!.toInt();
     localMax = null;
     localMin = null;
 
@@ -108,7 +108,7 @@ class _MicStreamExampleAppState extends State<MicStreamExampleApp>
       startTime = DateTime.now();
     });
     visibleSamples = [];
-    listener = stream.listen(_calculateSamples);
+    listener = stream!.listen(_calculateSamples);
     return true;
   }
 
@@ -121,7 +121,7 @@ class _MicStreamExampleAppState extends State<MicStreamExampleApp>
 
   void _calculateWaveSamples(samples) {
     bool first = true;
-    visibleSamples = List();
+    visibleSamples = [];
     int tmp = 0;
     for (int sample in samples) {
       if (sample > 128) sample -= 255;
@@ -133,8 +133,8 @@ class _MicStreamExampleAppState extends State<MicStreamExampleApp>
 
         localMax ??= visibleSamples.last;
         localMin ??= visibleSamples.last;
-        localMax = max(localMax, visibleSamples.last);
-        localMin = min(localMin, visibleSamples.last);
+        localMax = max(localMax!, visibleSamples.last);
+        localMin = min(localMin!, visibleSamples.last);
 
         tmp = 0;
       }
@@ -146,20 +146,20 @@ class _MicStreamExampleAppState extends State<MicStreamExampleApp>
   void _calculateIntensitySamples(samples) {
     currentSamples ??= [];
     int currentSample = 0;
-    eachWithIndex(samples, (i, sample) {
+    eachWithIndex(samples, (i, int sample) {
       currentSample += sample;
       if ((i % bytesPerSample) == bytesPerSample-1) {
-        currentSamples.add(currentSample);
+        currentSamples!.add(currentSample);
         currentSample = 0;
       }
     });
 
-    if (currentSamples.length >= samplesPerSecond/10) {
-      visibleSamples.add(currentSamples.map((i) => i).toList().reduce((a, b) => a+b));
+    if (currentSamples!.length >= samplesPerSecond/10) {
+      visibleSamples.add(currentSamples!.map((i) => i).toList().reduce((a, b) => a+b));
       localMax ??= visibleSamples.last;
       localMin ??= visibleSamples.last;
-      localMax = max(localMax, visibleSamples.last);
-      localMin = min(localMin, visibleSamples.last);
+      localMax = max(localMax!, visibleSamples.last);
+      localMin = min(localMin!, visibleSamples.last);
       currentSamples = [];
       setState(() {}); 
     }
@@ -275,19 +275,19 @@ class _MicStreamExampleAppState extends State<MicStreamExampleApp>
   void dispose() {
     listener.cancel();
     controller.dispose();
-    WidgetsBinding.instance.removeObserver(this);
+    WidgetsBinding.instance!.removeObserver(this);
     super.dispose();
   }
 }
 
 class WavePainter extends CustomPainter {
-  int localMax;
-  int localMin;
-  List<int> samples;
-  List<Offset> points;
-  Color color;
-  BuildContext context;
-  Size size;
+  int? localMax;
+  int? localMin;
+  List<int>? samples;
+  late List<Offset> points;
+  Color? color;
+  BuildContext? context;
+  Size? size;
 
   // Set max val possible in stream, depending on the config
   // int absMax = 255*4; //(AUDIO_FORMAT == AudioFormat.ENCODING_PCM_8BIT) ? 127 : 32767;
@@ -296,16 +296,16 @@ class WavePainter extends CustomPainter {
   WavePainter({this.samples, this.color, this.context, this.localMax, this.localMin});
 
   @override
-  void paint(Canvas canvas, Size size) {
-    this.size = context.size;
+  void paint(Canvas canvas, Size? size) {
+    this.size = context!.size;
     size = this.size;
 
     Paint paint = new Paint()
-      ..color = color
+      ..color = color!
       ..strokeWidth = 1.0
       ..style = PaintingStyle.stroke;
 
-    if (samples.length == 0)
+    if (samples!.length == 0)
       return; 
 
 
@@ -321,13 +321,13 @@ class WavePainter extends CustomPainter {
   bool shouldRepaint(CustomPainter oldPainting) => true;
 
   // Maps a list of ints and their indices to a list of points on a cartesian grid
-  List<Offset> toPoints(List<int> samples) {
+  List<Offset> toPoints(List<int>? samples) {
     List<Offset> points = [];
     if (samples == null)
-      samples = List<int>.filled(size.width.toInt(), (0.5).toInt());
-    double pixelsPerSample = size.width/samples.length;
+      samples = List<int>.filled(size!.width.toInt(), (0.5).toInt());
+    double pixelsPerSample = size!.width/samples.length;
     for (int i = 0; i < samples.length; i++) {
-      var point = Offset(i * pixelsPerSample, 0.5 * size.height * pow((samples[i] - localMin)/(localMax - localMin), 5));
+      var point = Offset(i * pixelsPerSample, 0.5 * size!.height * pow((samples[i] - localMin!)/(localMax! - localMin!), 5));
       points.add(point);
     }
     return points;
@@ -341,7 +341,7 @@ class WavePainter extends CustomPainter {
 
 class Statistics extends StatelessWidget {
   final bool isRecording;
-  final DateTime startTime;
+  final DateTime? startTime;
 
   final String url = "https://github.com/anarchuser/mic_stream";
 
@@ -360,7 +360,7 @@ class Statistics extends StatelessWidget {
       ListTile(
           leading: Icon(Icons.access_time),
           title: Text((isRecording
-              ? DateTime.now().difference(startTime).toString()
+              ? DateTime.now().difference(startTime!).toString()
               : "Not recording"))),
     ]);
   }

example/pubspec.yaml

@@ -3,15 +3,15 @@ description: Demonstrates how to use the mic_stream plugin.
 publish_to: 'none'
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   flutter:
     sdk: flutter
 
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
-  cupertino_icons: ^0.1.2
+  cupertino_icons: ^1.0.4
   path_provider: 
 dev_dependencies:
   flutter_test:

lib/mic_stream.dart

@@ -40,18 +40,18 @@ class MicStream {
       MethodChannel('aaron.code.com/mic_stream_method_channel');
 
   /// The actual sample rate used for streaming.  This may return zero if invoked without listening to the _microphone Stream
-  static Future<double> _sampleRate;
-  static Future<double> get sampleRate => _sampleRate;
+  static Future<double>? _sampleRate;
+  static Future<double>? get sampleRate => _sampleRate;
 
   /// The actual bit depth used for streaming. This may return zero if invoked without listening to the _microphone Stream first.
-  static Future<int> _bitDepth;
-  static Future<int> get bitDepth => _bitDepth;
+  static Future<int>? _bitDepth;
+  static Future<int>? get bitDepth => _bitDepth;
 
-  static Future<int> _bufferSize;
-  static Future<int> get bufferSize => _bufferSize;
+  static Future<int>? _bufferSize;
+  static Future<int>? get bufferSize => _bufferSize;
 
   /// The configured microphone stream;
-  static Stream<Uint8List> _microphone;
+  static Stream<Uint8List>? _microphone;
 
   // This function manages the permission and ensures you're allowed to record audio
   static Future<bool> get permissionStatus async {
@@ -70,16 +70,16 @@ class MicStream {
   /// channelConfig:   States whether audio is mono or stereo
   /// audioFormat:     Switch between 8- and 16-bit PCM streams
   ///
-  static Future<Stream<Uint8List>> microphone(
+  static Future<Stream<Uint8List>?> microphone(
       {AudioSource audioSource: _DEFAULT_AUDIO_SOURCE,
       int sampleRate: _DEFAULT_SAMPLE_RATE,
       ChannelConfig channelConfig: _DEFAULT_CHANNELS_CONFIG,
       AudioFormat audioFormat: _DEFAULT_AUDIO_FORMAT}) async {
     if (sampleRate < _MIN_SAMPLE_RATE || sampleRate > _MAX_SAMPLE_RATE)
       throw (RangeError.range(sampleRate, _MIN_SAMPLE_RATE, _MAX_SAMPLE_RATE));
-    if (!(await permissionStatus)) throw (PlatformException);
+    if (!(await permissionStatus))
+      throw (PlatformException);
 
-    print("Receive pbroadacast stream");
     _microphone = _microphone ??
         _microphoneEventChannel.receiveBroadcastStream([
           audioSource.index,
@@ -91,25 +91,23 @@ class MicStream {
     // sampleRate/bitDepth should be populated before any attempt to consume the stream externally.
     // configure these as Completers and listen to the stream internally before returning
     // these will complete only when this internal listener is called
-    StreamSubscription<Uint8List> listener;
+    StreamSubscription<Uint8List>? listener;
     var sampleRateCompleter = new Completer<double>();
     var bitDepthCompleter = new Completer<int>();
     var bufferSizeCompleter = new Completer<int>();
     _sampleRate = sampleRateCompleter.future;
     _bitDepth = bitDepthCompleter.future;
     _bufferSize = bufferSizeCompleter.future;
 
-    print("LISTEN NOW: $_microphone");
-    listener = _microphone.listen((x) async {
-    print("listening........");
-      await listener.cancel();
+    listener = _microphone!.listen((x) async {
+      await listener!.cancel();
       listener = null;
       sampleRateCompleter.complete(await _microphoneMethodChannel
-          .invokeMethod("getSampleRate") as double);
+          .invokeMethod("getSampleRate") as double?);
       bitDepthCompleter.complete(
-          await _microphoneMethodChannel.invokeMethod("getBitDepth") as int);
+          await _microphoneMethodChannel.invokeMethod("getBitDepth") as int?);
       bufferSizeCompleter.complete(
-          await _microphoneMethodChannel.invokeMethod("getBufferSize") as int);
+          await _microphoneMethodChannel.invokeMethod("getBufferSize") as int?);
     });
 
     return _microphone;

pubspec.yaml

@@ -1,10 +1,10 @@
 name: mic_stream
 description: Provides a tool to get the microphone input as PCM Stream
-version: 0.5.2
+version: 0.5.3
 homepage: https://github.com/anarchuser
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
   flutter: ">=2.0.1"
 
 module:
@@ -13,7 +13,7 @@ module:
 dependencies:
   flutter:
     sdk: flutter
-  permission_handler: ^8.1.4
+  permission_handler: ^8.2.6
 
 # For information on the generic Dart part of this file, see the
 # following page: https://www.dartlang.org/tools/pub/pubspec