flutterEmpty/lib/components/playing_control.dart

import 'package:assets_audio_player/assets_audio_player.dart';
import 'package:flutter/material.dart';
import 'package:flutter/painting.dart';


class PlayingControls extends StatelessWidget {

  final bool isPlaying;
  final LoopMode loopMode;
  final bool isPlaylist;
  final Function() onPrevious;
  final Function() onPlay;
  final Function() onNext;
  final Function() toggleLoop;
  final Function() onStop;

  PlayingControls({
    @required this.isPlaying,
    this.isPlaylist = false,
    this.loopMode,
    this.toggleLoop,
    this.onPrevious,
    @required this.onPlay,
    this.onNext,
    this.onStop,
  });

  Widget _loopIcon(BuildContext context) {
    final iconSize = 24.0;
    if( loopMode == LoopMode.none) {
      return Icon(Icons.loop,size: iconSize,color: Colors.white,);
    } else if(loopMode == LoopMode.playlist) {
      return Icon(Icons.loop,size: iconSize,color: Colors.white,);
    } else {
      return Stack(
        alignment: Alignment.center,
        children: [
          Icon(Icons.loop,size: iconSize,color: Colors.white,),
          Center(
            child: Text('1',style: TextStyle(fontSize: 9,fontWeight: FontWeight.bold,color: Colors.white),),
          )
        ],
      );
    }

    return Radio(
        value: LoopMode.playlist,
        groupValue: this.loopMode,
        onChanged: (newValue) {
          toggleLoop();
        }
    );
  }

  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        GestureDetector(
          onTap: (){
            toggleLoop();
          },
          child: _loopIcon(context),
        ),
        SizedBox(width: 10,),
        IconButton(
          icon: Icon(isPlaying ? Icons.pause : Icons.play_arrow,size: 24,color: Colors.white,),
            onPressed: this.onPlay
        ),
        if( onStop != null )
          IconButton(
            icon: Icon(Icons.stop,size: 24,color: Colors.white,),
              onPressed: this.onStop
          )
      ],
    );
  }
}