Add seekToNext/Previous, hasNext/Previous, polish example.

README.md

@@ -62,6 +62,8 @@ await player.load(
     ],
   ),
 );
+player.seekToNext();
+player.seekToPrevious();
 // Jump to the beginning of track3.mp3.
 player.seek(Duration(milliseconds: 0), index: 2);
 ```

example/lib/main.dart

@@ -1,8 +1,8 @@
 import 'dart:math';
 
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:just_audio/just_audio.dart';
-import 'package:rxdart/rxdart.dart';
 
 void main() => runApp(MyApp());
 
@@ -12,8 +12,6 @@ class MyApp extends StatefulWidget {
 }
 
 class _MyAppState extends State<MyApp> {
-  final _volumeSubject = BehaviorSubject.seeded(1.0);
-  final _speedSubject = BehaviorSubject.seeded(1.0);
   AudioPlayer _player;
   ConcatenatingAudioSource _playlist = ConcatenatingAudioSource(children: [
     LoopingAudioSource(
@@ -26,6 +24,8 @@ class _MyAppState extends State<MyApp> {
         tag: AudioMetadata(
           album: "Science Friday",
           title: "A Salute To Head-Scratching Science (5 seconds)",
+          artwork:
+              "https://media.wnyc.org/i/1400/1400/l/80/1/ScienceFriday_WNYCStudios_1400.jpg",
         ),
       ),
     ),
@@ -35,6 +35,8 @@ class _MyAppState extends State<MyApp> {
       tag: AudioMetadata(
         album: "Science Friday",
         title: "A Salute To Head-Scratching Science",
+        artwork:
+            "https://media.wnyc.org/i/1400/1400/l/80/1/ScienceFriday_WNYCStudios_1400.jpg",
       ),
     ),
     AudioSource.uri(
@@ -42,6 +44,8 @@ class _MyAppState extends State<MyApp> {
       tag: AudioMetadata(
         album: "Science Friday",
         title: "From Cat Rheology To Operatic Incompetence",
+        artwork:
+            "https://media.wnyc.org/i/1400/1400/l/80/1/ScienceFriday_WNYCStudios_1400.jpg",
       ),
     ),
   ]);
@@ -56,6 +60,9 @@ class _MyAppState extends State<MyApp> {
     super.initState();
     AudioPlayer.setIosCategory(IosCategory.playback);
     _player = AudioPlayer();
+    SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle(
+      statusBarColor: Colors.black,
+    ));
     _loadAudio();
   }
 
@@ -77,16 +84,15 @@ class _MyAppState extends State<MyApp> {
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
+      debugShowCheckedModeBanner: false,
       home: Scaffold(
-        appBar: AppBar(
+        body: SafeArea(
-          title: const Text('Audio Player Demo'),
-        ),
-        body: Center(
           child: Column(
             crossAxisAlignment: CrossAxisAlignment.center,
             mainAxisAlignment: MainAxisAlignment.center,
             children: [
-              StreamBuilder<int>(
+              Expanded(
+                child: StreamBuilder<int>(
                   stream: _player.currentIndexStream,
                   builder: (context, snapshot) {
                     final index = snapshot.data ?? 0;
@@ -94,6 +100,13 @@ class _MyAppState extends State<MyApp> {
                     return Column(
                       crossAxisAlignment: CrossAxisAlignment.center,
                       children: [
+                        Expanded(
+                          child: Padding(
+                            padding: const EdgeInsets.all(8.0),
+                            child:
+                                Center(child: Image.network(metadata.artwork)),
+                          ),
+                        ),
                         Text(metadata.album ?? '',
                             style: Theme.of(context).textTheme.headline6),
                         Text(metadata.title ?? ''),
@@ -101,6 +114,7 @@ class _MyAppState extends State<MyApp> {
                     );
                   },
                 ),
+              ),
               StreamBuilder<PlayerState>(
                 stream: _player.playerStateStream,
                 builder: (context, snapshot) {
@@ -110,6 +124,25 @@ class _MyAppState extends State<MyApp> {
                   return Row(
                     mainAxisSize: MainAxisSize.min,
                     children: [
+                      IconButton(
+                        icon: Icon(Icons.volume_up),
+                        onPressed: () {
+                          _showSliderDialog(
+                            context: context,
+                            title: "Adjust volume",
+                            divisions: 10,
+                            min: 0.0,
+                            max: 1.0,
+                            stream: _player.volumeStream,
+                            onChanged: _player.setVolume,
+                          );
+                        },
+                      ),
+                      IconButton(
+                        icon: Icon(Icons.skip_previous),
+                        onPressed:
+                            _player.hasPrevious ? _player.seekToPrevious : null,
+                      ),
                       if (processingState == ProcessingState.loading ||
                           processingState == ProcessingState.buffering)
                         Container(
@@ -137,11 +170,32 @@ class _MyAppState extends State<MyApp> {
                           onPressed: () =>
                               _player.seek(Duration.zero, index: 0),
                         ),
+                      IconButton(
+                        icon: Icon(Icons.skip_next),
+                        onPressed: _player.hasNext ? _player.seekToNext : null,
+                      ),
+                      IconButton(
+                        icon: StreamBuilder<double>(
+                            stream: _player.speedStream,
+                            builder: (context, snapshot) => Text(
+                                "${snapshot.data?.toStringAsFixed(1)}x",
+                                style: TextStyle(fontWeight: FontWeight.bold))),
+                        onPressed: () {
+                          _showSliderDialog(
+                            context: context,
+                            title: "Adjust speed",
+                            divisions: 10,
+                            min: 0.5,
+                            max: 1.5,
+                            stream: _player.speedStream,
+                            onChanged: _player.setSpeed,
+                          );
+                        },
+                      ),
                     ],
                   );
                 },
               ),
-              Text("Track position"),
               StreamBuilder<Duration>(
                 stream: _player.durationStream,
                 builder: (context, snapshot) {
@@ -164,34 +218,7 @@ class _MyAppState extends State<MyApp> {
                   );
                 },
               ),
-              Text("Volume"),
+              SizedBox(height: 8.0),
-              StreamBuilder<double>(
-                stream: _volumeSubject.stream,
-                builder: (context, snapshot) => Slider(
-                  divisions: 20,
-                  min: 0.0,
-                  max: 2.0,
-                  value: snapshot.data ?? 1.0,
-                  onChanged: (value) {
-                    _volumeSubject.add(value);
-                    _player.setVolume(value);
-                  },
-                ),
-              ),
-              Text("Speed"),
-              StreamBuilder<double>(
-                stream: _speedSubject.stream,
-                builder: (context, snapshot) => Slider(
-                  divisions: 10,
-                  min: 0.5,
-                  max: 1.5,
-                  value: snapshot.data ?? 1.0,
-                  onChanged: (value) {
-                    _speedSubject.add(value);
-                    _player.setSpeed(value);
-                  },
-                ),
-              ),
               Row(
                 children: [
                   StreamBuilder<LoopMode>(
@@ -242,7 +269,8 @@ class _MyAppState extends State<MyApp> {
                   ),
                 ],
               ),
-              Expanded(
+              Container(
+                height: 240.0,
                 child: StreamBuilder<int>(
                   stream: _player.currentIndexStream,
                   builder: (context, snapshot) {
@@ -293,7 +321,9 @@ class _SeekBarState extends State<SeekBar> {
 
   @override
   Widget build(BuildContext context) {
-    return Slider(
+    return Stack(
+      children: [
+        Slider(
           min: 0.0,
           max: widget.duration.inMilliseconds.toDouble(),
           value: min(_dragValue ?? widget.position.inMilliseconds.toDouble(),
@@ -312,13 +342,68 @@ class _SeekBarState extends State<SeekBar> {
             }
             _dragValue = null;
           },
+        ),
+        Positioned(
+          right: 16.0,
+          bottom: 0.0,
+          child: Text(
+              RegExp(r'((^0*[1-9]\d*:)?\d{2}:\d{2})\.\d+$')
+                      .firstMatch("$_remaining")
+                      ?.group(1) ??
+                  '$_remaining',
+              style: Theme.of(context).textTheme.caption),
+        ),
+      ],
     );
   }
+
+  Duration get _remaining => widget.duration - widget.position;
+}
+
+_showSliderDialog({
+  BuildContext context,
+  String title,
+  int divisions,
+  double min,
+  double max,
+  String valueSuffix = '',
+  Stream<double> stream,
+  ValueChanged<double> onChanged,
+}) {
+  showDialog(
+    context: context,
+    builder: (context) => AlertDialog(
+      title: Text(title, textAlign: TextAlign.center),
+      content: StreamBuilder<double>(
+        stream: stream,
+        builder: (context, snapshot) => Container(
+          height: 100.0,
+          child: Column(
+            children: [
+              Text('${snapshot.data?.toStringAsFixed(1)}$valueSuffix',
+                  style: TextStyle(
+                      fontFamily: 'Fixed',
+                      fontWeight: FontWeight.bold,
+                      fontSize: 24.0)),
+              Slider(
+                divisions: divisions,
+                min: min,
+                max: max,
+                value: snapshot.data ?? 1.0,
+                onChanged: onChanged,
+              ),
+            ],
+          ),
+        ),
+      ),
+    ),
+  );
 }
 
 class AudioMetadata {
   final String album;
   final String title;
+  final String artwork;
 
-  AudioMetadata({this.album, this.title});
+  AudioMetadata({this.album, this.title, this.artwork});
 }

example/pubspec.lock

@@ -178,7 +178,7 @@ packages:
     source: hosted
     version: "3.0.13"
   rxdart:
-    dependency: "direct main"
+    dependency: transitive
     description:
       name: rxdart
       url: "https://pub.dartlang.org"

example/pubspec.yaml

@@ -7,7 +7,6 @@ dependencies:
     sdk: flutter
 
   cupertino_icons: ^0.1.2
-  rxdart: ^0.24.0
 
 dev_dependencies:
   flutter_test:

lib/just_audio.dart

@@ -222,6 +222,16 @@ class AudioPlayer {
   /// A stream broadcasting the current item.
   Stream<int> get currentIndexStream => _currentIndexSubject.stream;
 
+  /// Whether there is another item after the current index.
+  bool get hasNext =>
+      _audioSource != null &&
+      currentIndex != null &&
+      currentIndex + 1 < _audioSource.sequence.length;
+
+  /// Whether there is another item before the current index.
+  bool get hasPrevious =>
+      _audioSource != null && currentIndex != null && currentIndex > 0;
+
   /// The current loop mode.
   LoopMode get loopMode => _loopModeSubject.value;
 
@@ -268,7 +278,7 @@ class AudioPlayer {
       _positionSubject.addStream(createPositionStream(
           steps: 800,
           minPeriod: Duration(milliseconds: 16),
-          maxPeriod: Duration(milliseconds: 11200)));
+          maxPeriod: Duration(milliseconds: 200)));
     }
     return _positionSubject.stream;
   }
@@ -515,6 +525,20 @@ class AudioPlayer {
     }
   }
 
+  /// Seek to the next item.
+  Future<void> seekToNext() async {
+    if (hasNext) {
+      await seek(Duration.zero, index: currentIndex + 1);
+    }
+  }
+
+  /// Seek to the previous item.
+  Future<void> seekToPrevious() async {
+    if (hasPrevious) {
+      await seek(Duration.zero, index: currentIndex - 1);
+    }
+  }
+
   /// Release all resources associated with this player. You must invoke this
   /// after you are done with the player.
   Future<void> dispose() async {