uni.createInnerAudioContext()

创建并返回内部 audio 上下文 innerAudioContext 对象。

解决方法：

onCanplay 音频进入可以播放状态 添加定时器获取音频时长

const innerAudioContext = uni.createInnerAudioContext();
innerAudioContext.autoplay = true;
innerAudioContext.src = 'https://bjetxgzv.cdn.bspapp.com/VKCEYUGU-hello-uniapp/2cc220e0-c27a-11ea-9dfb-6da8e309e0d8.mp3';
innerAudioContext.onPlay(() => {
  console.log('开始播放');
});
innerAudioContext.onCanplay(() => {
    let intervalID = setInterval(() => {
      if (innerAudioContext.duration !== 0) {
        clearInterval(intervalID);
        console.log("音频时长", innerAudioContext.duration);
      }
    }, 500);
});
innerAudioContext.onError((res) => {
  console.log(res.errMsg);
  console.log(res.errCode);
});