Method loadUnitByIndex

js/ReadingSystem.js:294–342

* 根据索引加载指定单元 * @param {number} unitIndex - 单元索引 * @param {Object} [options={}] - 选项 * @returns {Promise }

(unitIndex, options = {})

   * @returns {Promise<void>}
   */
  async loadUnitByIndex(unitIndex, options = {}) {
    const { shouldScrollUnitIntoView = false } = options;

    this.state.currentUnitIndex = unitIndex;
    saveCurrentUnitIndex(this.state.bookPath, unitIndex);

    const unit = this.state.units[unitIndex];
    if (!unit) return;

    this.resetPlayer();
    this.updateActiveUnit(unitIndex, { shouldScrollUnitIntoView });
    this.updateNavigationButtons();

    // 加载歌词
    try {
      let lrcText = this.lrcCache.get(unit.lrc);
      if (!lrcText) {
        const response = await fetch(unit.lrc);
        lrcText = await response.text();
        this.lrcCache.set(unit.lrc, lrcText);
      }

      this.state.currentLyrics = LRCParser.parse(
        lrcText,
        this.config.PLAYER.TIME_OFFSET
      );
      this.renderLyrics();
    } catch (error) {
      console.error(this.config.ERROR_MESSAGES.LOAD_LYRIC, error);
      if (this.dom.lyricsDisplay) {
        setHTML(this.dom.lyricsDisplay, `<p class="placeholder">${this.config.ERROR_MESSAGES.LOAD_FAILED}</p>`);
      }
    }

    // 设置音频源
    if (this.dom.audioPlayer) {
      this.setPlayButtonDisabled(true);
      this.dom.audioPlayer.src = unit.audio;
      this.dom.audioPlayer.loop = this.state.loopMode === 'list';
      this.dom.audioPlayer.load();
    }

    // 恢复播放进度和速度
    this.loadPlayTime();
    this.loadSavedSpeed();

    // 预加载下一个单元
    this.prefetchUnit(unitIndex + 1);
  }

  /**
   * 重置播放器