需要通过触发stateChange才能暂停播放，可以参考下这个示例：

import media from '@ohos.multimedia.media';
import { BusinessError } from '@ohos.base';
import common from '@ohos.app.ability.common';

// 音频播放
export class AVPlayerDemo {
  public flag: number = 1;
  public static avPlayerCom: media.AVPlayer;
  public static avFileDescriptorCom: media.AVFileDescriptor;
  public curAudioPath: string = '';
  public avFileDescriptor4: media.AVFileDescriptor | undefined = undefined;
  public isLoop: boolean = false;
  private avPlayer: media.AVPlayer | null = null;

  // 注册avplayer回调函数
  setAVPlayerCallback(avPlayer: media.AVPlayer): void {
    // seek操作结果回调函数
    avPlayer.on('seekDone', (seekDoneTime: number) => {
      console.info(`AVPlayer seek succeeded, seek time is ${seekDoneTime}`);
    })
    // error回调监听函数,当avPlayer在操作过程中出现错误时调用 reset接口触发重置流程
    avPlayer.on('error', (err: BusinessError) => {
      console.error(`Invoke avPlayer failed, code is ${err.code}, message is ${err.message}`);
      avPlayer.reset(); // 调用reset重置资源，触发idle状态
    })
    // 状态机变化回调函数
    avPlayer.on('stateChange', async (state: string, _: media.StateChangeReason) => {
      switch (state) {
        case 'idle': // 成功调用reset接口后触发该状态机上报
          console.info('AVPlayer state idle called.');
          avPlayer.release(); // 调用release接口销毁实例对象
          break;
        case 'initialized': // avplayer 设置播放源后触发该状态上报
          console.info('AVPlayer state initialized called.');
          avPlayer.prepare();
          break;
        case 'prepared': // prepare调用成功后上报该状态机
          console.info('AVPlayer state prepared called.');
          avPlayer.play(); // 调用播放接口开始播放
          break;
        case 'playing': // play成功调用后触发该状态机上报
          console.info('AVPlayer state playing called.');
          break;
        case 'paused': // pause成功调用后触发该状态机上报
          console.info('AVPlayer state paused called.');
          break;
        case 'completed': // 播放结束后触发该状态机上报
          console.info('AVPlayer state completed called.');
          if (this.isLoop) {
            avPlayer.play()
          } else {
            avPlayer.stop(); //调用播放结束接口
          }
          break;
        case 'stopped': // stop接口成功调用后触发该状态机上报
          console.info('AVPlayer state stopped called.');
          avPlayer.reset(); // 调用reset接口初始化avplayer状态
          break;
        case 'released':
          console.info('AVPlayer state released called.');
          break;
        default:
          console.info('AVPlayer state unknown called.');
          break;
      }
    })
  }
  async avPlayerUrlDemo(): Promise<void> {
    // 创建avPlayer实例对象
    try {
      this.avPlayer = await media.createAVPlayer();
      this.avPlayer.audioRendererInfo
      // 创建状态机变化回调函数
      await this.setAVPlayerCallback(this.avPlayer);
      // 通过UIAbilityContext获取沙箱地址filesDir，以Stage模型为例
      const context = getContext(this) as common.UIAbilityContext;
      let fileDescriptor = await context.resourceManager.getRawFd('AV_1739446770000.m4a');
      let avFileDescriptor: media.AVFileDescriptor =
        { fd: fileDescriptor.fd, offset: fileDescriptor.offset, length: fileDescriptor.length };
      // 测试可以播放
      this.avPlayer.fdSrc = avFileDescriptor;
      AVPlayerDemo.avFileDescriptorCom = avFileDescriptor;
    } catch (e) {
    }
  }

  async StopPlayer(): Promise<void> {
    try {
      this.avPlayer?.stop();
    } catch (e) {
    }
  }

  async PausePlayer(): Promise<void> {
    try {
      this.avPlayer?.pause();
    } catch (e) {
    }
  }

  async PauseedPlayer(): Promise<void> {
    try {
      this.avPlayer?.play();
    } catch (e) {
    }
  }
}
@Entry
@Component
export struct AVPlayerSimple {
  avPlayer = new AVPlayerDemo();

  build() {
    Column() {
      Button('播放音频')
        .onClick(() => {
          this.avPlayer.avPlayerUrlDemo().then(() => {
          });
        })
        .width('100')
        .height('100')
      Button('暂停播放')
        .onClick(() => {
          this.avPlayer.PausePlayer()
        })
        .width('100')
        .height('100')
      Button('继续播放')
        .onClick(() => {
          this.avPlayer.PauseedPlayer()
        })
        .width('100')
        .height('100')
      Button('停止播放')
        .onClick(() => {
          this.avPlayer.StopPlayer().then(() => {
          });
        })
        .width('100')
        .height('100')
      Button('循环播放')
        .onClick(() => {
          this.avPlayer.isLoop = true;
        })
        .width('100')
        .height('100')
    }
    .width('200')
    .height('200')
  }
}