iOS 15：锁定屏幕几分钟后，Web 音频播放在 Safari 中停止工作答案

【问题标题】：iOS 15: Web Audio playback stops working in Safari after locking screen for a few minutesiOS 15：锁定屏幕几分钟后，Web 音频播放在 Safari 中停止工作
【发布时间】：2021-11-28 19:05:42
【问题描述】：

这似乎是我将 iPod Touch 升级到 iOS 15 (15.0.1) 后出现的问题。

运行下面的示例时，它在第一次加载时运行良好，可以根据需要多次播放声音。但是，如果我在 iPod Touch 上锁定屏幕，然后在几分钟后返回，声音将不再播放。为了排除故障，我在 AudioContext 实例上设置了一个状态更改侦听器，并验证了 Safari 在屏幕锁定时将状态设置回running 后将其设置为interrupted。但是，声音没有播放。

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>audio-test</title>
    </head>
    <body>
        <script>

            const AudioContext = window.AudioContext || window.webkitAudioContext;
            const audioContext = new AudioContext();

            // Create AudioBuffer and fill with two seconds of white noise.
            const channels = 2;
            const frameCount = audioContext.sampleRate * 2.0;
            const audioBuffer = audioContext.createBuffer(channels, frameCount, audioContext.sampleRate);
            for (var channel = 0; channel < channels; channel++) {
                var nowBuffering = audioBuffer.getChannelData(channel);
                for (var i = 0; i < frameCount; i++) {
                    nowBuffering[i] = Math.random() * 2 - 1;
                }
            }

            const button = document.createElement('button');
            button.textContent = 'Play Audio';
            document.body.append(button);

            button.addEventListener('click', () => {
                const currentSourceNode = new AudioBufferSourceNode(audioContext, {
                    buffer: audioBuffer,
                });
                currentSourceNode.connect(audioContext.destination);
                currentSourceNode.start();
            });

        </script>
    </body>
</html>

【问题讨论】：

标签： javascript html ios mobile-safari web-audio-api

【解决方案1】：

奇怪的是，如果我在指向某个 mp3 文件的 HTML 中添加了一个音频元素，而该文件甚至根本没有在代码中引用，那么锁定屏幕一段时间然后返回页面不再影响音频播放。

更新代码：

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>audio-test</title>
    </head>
    <body>
        <script>

            const AudioContext = window.AudioContext || window.webkitAudioContext;
            const audioContext = new AudioContext();

            // Create AudioBuffer and fill with two seconds of white noise.
            const channels = 2;
            const frameCount = audioContext.sampleRate * 2.0;
            const audioBuffer = audioContext.createBuffer(channels, frameCount, audioContext.sampleRate);
            for (var channel = 0; channel < channels; channel++) {
                var nowBuffering = audioBuffer.getChannelData(channel);
                for (var i = 0; i < frameCount; i++) {
                    nowBuffering[i] = Math.random() * 2 - 1;
                }
            }

            const button = document.createElement('button');
            button.textContent = 'Play Audio';
            document.body.append(button);

            button.addEventListener('click', () => {
                const currentSourceNode = new AudioBufferSourceNode(audioContext, {
                    buffer: audioBuffer,
                });
                currentSourceNode.connect(audioContext.destination);
                currentSourceNode.start();
            });

        </script>
        <audio src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/858/outfoxing.mp3" crossorigin="anonymous"></audio>
    </body>
</html>

【讨论】：