Flutter中的背景音乐不起作用

如何解决Flutter中的背景音乐不起作用

我正在尝试将背景音乐添加到我的应用中。如果我启动我的应用程序，则音乐会正确播放，但是如果我按下对音乐没有影响的按钮，则音乐将从新开始。我用Flutter编写代码。这是我删除不重要内容的代码。

import 'package:audioplayers/audio_cache.dart';
import 'package:audioplayers/audioplayers.dart';


class _MyHomepageState extends State<MyHomepage> {
  AudioPlayer player = AudioPlayer();
  AudioCache cache = new AudioCache();
  bool isPlaying = false;

  Future<bool> _willPopCallback() async {
    if (isPlaying == false) {
      setState(() {
        isPlaying = true;
      });
      player.stop();
    }
    return true;
  }

  openingActions() async {
    player = await cache.loop('audio/test.mp3');
  }

 
  @override
  Widget build(BuildContext context) {
    openingActions();
    return WillPopScope(
        onWillPop: () => _willPopCallback(),child: Scaffold(
          body: Container(
            decoration: Boxdecoration(
              image: decorationImage(
                image: Assetimage('assets/images/background.jpg'),fit: BoxFit.cover,),...
    ...
    ...
raisedbutton(
....
)

解决方法

您可以在下面复制粘贴运行完整代码
您可以将openingActions();从build移到initState
并且rebuild将不会再次调用openingActions();

@override
  void initState() {
    openingActions();
    super.initState();
  }

@override
  Widget build(BuildContext context) {
    //openingActions(); //delete this line and move to initState

完整代码

import 'package:flutter/material.dart';
import 'package:audioplayers/audio_cache.dart';
import 'package:audioplayers/audioplayers.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',theme: ThemeData(
        primarySwatch: Colors.blue,visualDensity: VisualDensity.adaptivePlatformDensity,),home: MyHomePage(title: 'Flutter Demo Home Page'),);
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key,this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  AudioPlayer player = AudioPlayer();
  AudioCache cache = new AudioCache();
  bool isPlaying = false;

  Future<bool> _willPopCallback() async {
    if (isPlaying == false) {
      setState(() {
        isPlaying = true;
      });
      player.stop();
    }
    return true;
  }

  openingActions() async {
    player = await cache.loop('audio/test.mp3');
  }

  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  void initState() {
    openingActions();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[
            RaisedButton(
              child: Text('Open route'),onPressed: () {
                setState(() {});
              },Text(
              'You have pushed the button this many times:',Text(
              '$_counter',style: Theme.of(context).textTheme.headline4,],floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,tooltip: 'Increment',child: Icon(Icons.add),);
  }
}