HarmonyOS 应用开发-边缓存边播放案例

 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;
       })
   })

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 = new Map();

  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);
  }
}

  async initPlayer(context: common.UIAbilityContext, surfaceId: string,
                   callback: (avPlayer: media.AVPlayer) => void): Promise {
    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)}`);
    }
  }

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

    // TODO:知识点: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);
    // TODO:知识点: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;
  }

videocache                                         // har类型
|---model
|   |---GlobalProxyServer.ets                      // 模型层-服务器管理
|   |---VideoPlayerManager.ets                     // 模型层-音视频管理
|---utils
|   |---utils.ets                                  // 工具
|---view
|   |---VideoCacheView.ets                         // 视图层-应用主页面