Question

我正在尝试构建一个简单的苹果音乐网络应用播放器。我成功地得到了一个工作的小例子。我可以根据“类型”和“ id”将专辑，歌曲等加载到音乐播放器队列中。我无法播放，暂停，跳到下一首曲目，上一首曲目等，但是由于某种原因，当一首歌结束并且下一首开始播放时（由API播放器队列自动处理），或者我单击跳到下一首曲目，暂停等它会做其应做的事情，但会弹出错误消息。

例如：我将相册加载到队列中。点击播放。它开始播放音乐，但是有时它会在开始播放后立即随机弹出一条错误消息，并将错误打印到控制台。

这是开发控制台中显示的内容。 “未处理的承诺拒绝：PLAY_ACTIVITY：在没有先前的play（）描述符的情况下调用了play stop（）方法” https://imgur.com/5MCq08s

我尝试让js在切换曲目之前暂停歌曲，但这不能解决问题。

“未处理的承诺拒绝：PLAY_ACTIVITY：在没有先前play（）描述符的情况下调用了stop（）方法”

document.addEventListener('musickitloaded', () => {
    console.log("musickit loaded :D")
  // MusicKit global is now defined
  fetch('/token').then(response => response.json()).then(res => {
    /***
      Configure our MusicKit instance with the signed token from server, returns a configured MusicKit Instance
      https://developer.apple.com/documentation/musickitjs/musickit/musickitinstance
    ***/
    const music = MusicKit.configure({
      developerToken: res.token,
      app: {
        name: 'AppleMusicCS115',
        build: '0.0.1'
      },
      declarativeMarkup: true
    });

    // setup click handlers
    document.getElementById('add-to-q-btn').addEventListener('click', () => {
      const idInput   = document.getElementById('id-input');
      const typeInput = document.getElementById('type-input');

      /***
        Add an item to the playback queue
        https://developer.apple.com/documentation/musickitjs/musickit/musickitinstance/2992716-setqueue
      ***/
      music.setQueue({
        [typeInput.value]: idInput.value
      });
      // set fields back to blank fields
      idInput.value   = '';
      typeInput.value = '';
    });

    document.getElementById('play-btn').addEventListener('click', () => {
      /***
        Resume or start playback of media item
        https://developer.apple.com/documentation/musickitjs/musickit/musickitinstance/2992709-play
      ***/
     music.authorize().then(function() {
        music.play();
      });// added then function
    });

    document.getElementById('pause-btn').addEventListener('click', () => {
      /***
        Pause playback of media item
        https://developer.apple.com/documentation/musickitjs/musickit/musickitinstance/2992708-pause
      ***/
     music.authorize().then(function() {
        music.pause();
      });// added then function
    });

    document.getElementById('next-trk-btn').addEventListener('click', () => {
        /***
         * Skip to next item in queue.
         * https://developer.apple.com/documentation/musickitjs/musickit/player/2992772-skiptonextitem
         */
        music.authorize().then(function() {
            music.skipToNextItem();
          });// added then function



    });

    document.getElementById('prev-trk-btn').addEventListener('click', () => {
        /***
         * https://developer.apple.com/documentation/musickitjs/musickit/player/2992773-skiptopreviousitem
         */

        music.authorize().then(function() {
            music.pause();;
          });
        music.authorize().then(function() {
            music.skipToPreviousItem();;
          });// added then function
    })

</head>
<body>
  <label>Type (eg 'album' 'song')</label>
  <input id="type-input" type="text" value="album">
  <br>
  <label>id</label>
  <input id="id-input" type="text" value="1462319084">
  <br>
  <button id="add-to-q-btn">Add to Queue</button>
  <br>
  <hr>
  <button id="prev-trk-btn">Prev Track</button>
  <button id="play-btn">Play</button>
  <button id="pause-btn">Pause</button>
  <button id="next-trk-btn">Next Track</button>

  <button id="login-btn">Login to Apple Music</button>
  <br>

我希望它能在不显示任何弹出错误的情况下切换歌曲，播放，暂停等。也许以某种方式处理这些异常？控制台输出：

未处理的承诺拒绝： PLAY_ACTIVITY：调用了play stop（）方法而没有先前的play（）描述符（匿名函数）-musickit.js：1：14539 拒绝-musickit.js：534 promiseReactionJob

未处理的承诺拒绝：PLAY_ACTIVITY-Apple MusicKitJS API

0 个答案: