HarmonyOS 鸿蒙Next createAVPlayer.dataSrc的具体使用方式

可以使用OhosVideoCache实现边下边播的功能@ohos%2Fvideo-cache/v/1.0.1-rc.1

边缓存播放功能主要是通过Xcomponent组件、@ohos.multimedia.media以及OhosVideoCache三方库实现，XComponent组件主要用于绘制 视频播放的窗口，页面进来初始化服务器然后利用XComponent组件的onLoad函数来调用VideoPlayerManager 中的initPlayer方法创建一个音视频管理实例，并通过setAVPlayerCallback函数和cacheAndPlayVideo函数来实现视频状态的监听以及边缓存边播放功能。

1. XComponent组件绘制视频播放窗口

XComponent({
   id: 'xcomponent',
   type: 'surface',
   controller: this.componentController
 })
   .height(`${this.xComponentHeight}px`)
   .width(`${this.xComponentWidth}px`)
   .onLoad(() => {
     // 设置XComponent持有Surface的宽度和高度
     this.componentController.setXComponentSurfaceSize({
       surfaceWidth: SURFACE_WIDTH,
       surfaceHeight: SURFACE_HEIGHT
     });
     this.surfaceId = this.componentController.getXComponentSurfaceId();
     // 创建音视频播放实例
     AvPlayManager.getInstance()
       .initPlayer(getContext(this) as common.UIAbilityContext, this.surfaceId, (avPlayer: media.AVPlayer) => {
         avPlayer.on('timeUpdate', (time: number) => {
           this.currentTime = time;
         });
         this.videoDuration = handleTime(avPlayer.duration);
         this.total = avPlayer.duration;
       })
   })

1. 初始化代理服务器，页面一进来需要使用setServer方法来初始化代理服务器，以便后续调用此服务器处理url

import common from '@ohos.app.ability.common';
import { HttpProxyCacheServer } from '@ohos/video-cache';

const CONTEXT_STR: string = 'context';
const SERVER_STR: string = 'server';

export default class GlobalProxyServer {
  private static instance: GlobalProxyServer | null = null;
  private objects: Map<string, Object | null> = new Map<string, Object | null>();

  public static getInstance(): GlobalProxyServer {
    if (!GlobalProxyServer.instance) {
      GlobalProxyServer.instance = new GlobalProxyServer();
    }
    return GlobalProxyServer.instance;
  }

  /**
   * 获取上下文信息
   * @returns
   */
  getContext(): common.UIAbilityContext {
    return this.objects.get(CONTEXT_STR) as common.UIAbilityContext;
  }

  /**
   * 设置上下文信息
   * @param context
   */
  setContext(context: common.UIAbilityContext): void {
    this.objects.set(CONTEXT_STR, context);
  }

  /**
   * 获取服务器
   * @returns
   */
  getServer(): HttpProxyCacheServer {
    return this.objects.get(SERVER_STR) as HttpProxyCacheServer;
  }

  /**
   * 设置服务器
   * @param objectClass
   */
  setServer(objectClass: HttpProxyCacheServer): void {
    try {
      const currentServer: HttpProxyCacheServer = this.getServer();
      currentServer.shutdown();
    } catch (err) {
    }
    this.objects.set(SERVER_STR, objectClass);
  }
}

1. media.createAVPlayer()创建播放管理类，用于管理和播放媒体资源

async initPlayer(context: common.UIAbilityContext, surfaceId: string,
                 callback: (avPlayer: media.AVPlayer) => void): Promise<void> {
  logger.info(TAG, `initPlayer==initCamera surfaceId== ${surfaceId}`);
  this.surfaceID = surfaceId;
  try {
    // 创建avPlayer实例对象
    this.avPlayer = await media.createAVPlayer();
    // 创建状态机变化回调函数
    await this.setAVPlayerCallback(callback);
    // 边缓存边播放
    this.cacheAndPlayVideo(context);
  } catch (err) {
    logger.error(TAG, `initPlayer initPlayer err：${JSON.stringify(err)}`);
  }
}

1. 边播放边缓存，MyCacheListener监听缓存进度，getProxyUrl(ORIGIN_URL)获取视频播放地址并设置给播放器

/**
 * 边缓存边监听函数
 * @param context 上下文信息
 * @returns
 */
async cacheAndPlayVideo(context: common.UIAbilityContext): Promise<void> {
  logger.info(TAG, `cacheAndPlayVideo start`);

  // 监听缓存进度
  class MyCacheListener implements CacheListener {
    onCacheAvailable(cacheFilePath: string, url: string, percentsAvailable: number): void {
      AppStorage.setOrCreate('currentCachePercent', percentsAvailable);
    }
  }

  GlobalProxyServer?.getInstance()?.getServer()?.registerCacheListener(new MyCacheListener(), ORIGIN_URL);
  // 将原始的音视频url交给OhosVideoCache
  let proxyUrl: string | undefined = await GlobalProxyServer?.getInstance()?.getServer()?.getProxyUrl(ORIGIN_URL);
  // 由于avplayer不支持直接加载本地文件路径 这里需要转化为fd的路径
  if (proxyUrl.startsWith(context.cacheDir)) {
    const file = fs.openSync(proxyUrl, fs.OpenMode.READ_ONLY);
    proxyUrl = `fd://${file.fd}`;
  }
  logger.info(TAG, `proxyUrl ${proxyUrl}`);
  // 将处理之后的url设置给播放器
  this.avPlayer.url = proxyUrl;
}