自定义相机拍照前需要创建拍照输出流、进行拍照设置（如图片质量、旋转角度、是否镜像等），然后再调用capture方法将拍照设置传递到拍照输出流中。
应用开发时，经常需要使用一些急促简短的音效（如相机快门音效、系统通知音效等），此时可以使用SoundPool实现一次加载、多次低时延播放，详情可以参考使用SoundPool播放短音频。

解决方案

定义SoundPoolUtil类，使用SoundPool完成快门音效的播放。

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import { media } from '@kit.MediaKit';
import { audio } from '@kit.AudioKit';
import { BusinessError } from '@kit.BasicServicesKit';
import { hilog } from '@kit.PerformanceAnalysisKit';

const DOMAIN: number = 0x0000;
const TAG: string = '[SoundPoolPage]';

export class SoundPoolUtil {
  private soundPool: media.SoundPool | undefined = undefined;
  private soundId: number = 0;
  private streamId: number = 0;
  private currentContext: Context;

  constructor(uiContext: Context) {
    this.currentContext = uiContext;
    this.create();
  }

  async create() {
    try {
      // audioRenderInfo中的参数usage取值为STREAM_USAGE_UNKNOWN，STREAM_USAGE_MUSIC，STREAM_USAGE_MOVIE
      // STREAM_USAGE_AUDIOBOOK时，SoundPool播放短音时为混音模式，不会打断其他音频播放
      let audioRendererInfo: audio.AudioRendererInfo = {
        usage: audio.StreamUsage.STREAM_USAGE_MUSIC, // 音频流使用类型：音乐
        rendererFlags: 1 // 音频渲染器标志
      };
      // 创建soundPool实例
      this.soundPool = await media.createSoundPool(14, audioRendererInfo);
      // 注册监听
      this.loadCallback();
      this.finishPlayCallback();
      this.setErrorCallback();

      // 加载音频资源，开发者需要在resources/rawfile目录下替换成快门音频资源
      let fileDescriptor = await this.currentContext!.resourceManager.getRawFd('shutter.mp3');
      hilog.info(DOMAIN, TAG, `Successfully get the fileDescriptor: ${fileDescriptor}`);
      this.soundId = await this.soundPool!.load(fileDescriptor.fd, fileDescriptor.offset, fileDescriptor.length);
      hilog.info(DOMAIN, TAG, `Successfully load soundPool soundId: ${this.soundId}`);
    } catch (e) {
      hilog.error(DOMAIN, TAG, `CreateSoundPool error: ${e}`);
    }
  }

  async loadCallback() {
    // 加载完成回调
    this.soundPool!.on('loadComplete', (soundId_: number) => {
      this.soundId = soundId_;
      hilog.info(DOMAIN, TAG, `Successfully loadComplete soundId: ${soundId_}`);
    });
  }

  // 设置播放完成监听
  async finishPlayCallback() {
    this.soundPool!.on('playFinished', () => {
      hilog.info(DOMAIN, TAG, 'receive play finished message');
    });
  }

  // 设置错误类型监听
  async setErrorCallback() {
    this.soundPool!.on('error', (error: BusinessError) => {
      hilog.error(DOMAIN, TAG, `error happened,message is: ${error.code}`);
      hilog.error(DOMAIN, TAG, `error happened,message is: ${error.message}`);
    });
  }

  async PlaySoundPool() {
    let playParameters: media.PlayParameters = {
      loop: 0, // 循环0次，即播放1次
      rate: 1, // 1倍速播放
      leftVolume: 0.5, // 取值范围0.0-1.0
      rightVolume: 0.5, // 取值范围0.0-1.0
      priority: 0, // 最低优先级
    };
    // 开始播放，请在音频资源加载完毕，即收到loadComplete回调之后再执行play操作
    this.soundPool!.play(this.soundId, playParameters, (error, streamID: number) => {
      if (error) {
        hilog.error(DOMAIN, TAG, `play sound Error: errCode is ${error.code}, errMessage is ${error.message}`);
      } else {
        this.streamId = streamID;
        hilog.info(DOMAIN, TAG, `play success soundid: ${this.streamId}`);
      }
    });

    // 设置循环播放次数
    await this.soundPool!.setLoop(this.streamId, 1);
    // 设置对应流的优先级
    await this.soundPool!.setPriority(this.streamId, 1);
    // 设置音量
    await this.soundPool!.setVolume(this.streamId, 0.5, 0.5);
  }

  async release() {
    // 终止指定流的播放
    await this.soundPool!.stop(this.streamId);
    // 卸载音频资源
    await this.soundPool!.unload(this.soundId);
    // 关闭监听
    this.setOffCallback();
    // 释放SoundPool
    await this.soundPool!.release();
  }

  async setOffCallback() {
    this.soundPool!.off('loadComplete');
    this.soundPool!.off('playFinished');
    this.soundPool!.off('error');
  }
}

定义相机管理类CameraShooter，完成相机会话配置、拍照、保存至媒体库等操作：

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import { camera } from '@kit.CameraKit';
import { BusinessError } from '@kit.BasicServicesKit';
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { colorSpaceManager } from '@kit.ArkGraphics2D';
import { image } from '@kit.ImageKit';
import { hilog } from '@kit.PerformanceAnalysisKit';

const DOMAIN: number = 0x0000;
const TAG: string = '[CameraShooterPage]';

let previewOutput: camera.PreviewOutput;
let cameraInput: camera.CameraInput;
let photoSession: camera.PhotoSession;
let photoOutPut: camera.PhotoOutput;
let currentContext: Context;
// 期望的拍照图片尺寸
let imageSize: image.Size = { width: 1920, height: 1440 };

export async function cameraShooting(cameraPosition: number, surfaceId: string, context: Context): Promise<void> {
  currentContext = context;
  releaseCamera();
  try {
    // 获取相机管理对象
    let cameraManager: camera.CameraManager = camera.getCameraManager(context);
    let cameraArray: camera.CameraDevice[] = cameraManager.getSupportedCameras();
    if (cameraArray.length <= 0) {
      hilog.error(DOMAIN, TAG, 'No camera devices found!');
      return;
    }
    // 创建相机输入流
    cameraInput = cameraManager.createCameraInput(cameraArray[cameraPosition]);
    await cameraInput.open();
    // 获取支持的相机模式
    let sceneModes: camera.SceneMode[] = cameraManager.getSupportedSceneModes(cameraArray[cameraPosition]);
    // 获取支持的相机输出能力
    let cameraOutputCap: camera.CameraOutputCapability =
      cameraManager.getSupportedOutputCapability(cameraArray[cameraPosition], camera.SceneMode.NORMAL_PHOTO);
    let isSupportPhotoMode: boolean = sceneModes.indexOf(camera.SceneMode.NORMAL_PHOTO) >= 0;
    if (!isSupportPhotoMode) {
      hilog.error(DOMAIN, TAG, 'No supported photo mode found!');
      return;
    }
    if (!cameraOutputCap) {
      hilog.error(DOMAIN, TAG, 'No supported camera OutputCap found!');
      return;
    }
    // 获取预览流的Profile列表
    let previewProfilesArray: camera.Profile[] = cameraOutputCap.previewProfiles;
    // 创建预览输出流，surfaceId为显示组件的id
    let previewProfile: camera.Profile | undefined = undefined;
    for (let index = previewProfilesArray.length - 1; index >= 0; index--) {
      if (previewProfilesArray[index].size.width / previewProfilesArray[index].size.height ===
        imageSize.width / imageSize.height) {
        previewProfile = previewProfilesArray[index];
        break;
      }
    }

    previewOutput = cameraManager.createPreviewOutput(previewProfile, surfaceId);
    if (previewOutput === undefined) {
      return;
    }

    // 获取支持的拍照流profile
    let photoProfilesArray: camera.Profile[] = cameraOutputCap.photoProfiles.slice().reverse();
    let photoProfile: camera.Profile | undefined = undefined;
    if (previewProfile !== undefined) {
      // 选择与预览流分辨率宽高比一致的拍照流分辨率
      photoProfile = photoProfilesArray.find((profile: camera.Profile) => {
        return profile.size.height * previewProfile!.size.width === previewProfile!.size.height * profile.size.width;
      });
    }
    // 获取支持的拍照输出能力
    photoOutPut = cameraManager.createPhotoOutput(photoProfile);

    if (photoOutPut === undefined) {
      return;
    }
    // 保存图片
    setPhotoOutputCb(photoOutPut);
    // 创建相机会话
    photoSession = cameraManager.createSession(camera.SceneMode.NORMAL_PHOTO) as camera.PhotoSession;
    if (photoSession === undefined) {
      return;
    }
    // 开始相机会话
    photoSession.beginConfig();
    photoSession.addInput(cameraInput);
    photoSession.addOutput(previewOutput);
    photoSession.addOutput(photoOutPut);
    photoSession.setColorSpace(colorSpaceManager.ColorSpace.DISPLAY_P3);
    await photoSession.commitConfig();
    await photoSession.start();
  } catch (error) {
    hilog.error(DOMAIN, TAG, `The cameraShooting call failed. error: ${JSON.stringify(error)}`);
  }
}

// 拍照方法
export async function capture(isFront: boolean) {
  try {
    let settings: camera.PhotoCaptureSetting = {
      quality: camera.QualityLevel.QUALITY_LEVEL_HIGH,
      rotation: camera.ImageRotation.ROTATION_0,
      mirror: isFront
    };
    photoOutPut.capture(settings);
  } catch (error) {
    hilog.error(DOMAIN, TAG, `The capture call failed. error: ${error.code}`);
  }
}

// 释放相机相关资源
export async function releaseCamera(): Promise<void> {
  try {
    if (photoSession) {
      photoSession.stop();
    }
    if (cameraInput) {
      cameraInput.close();
    }
    if (previewOutput) {
      previewOutput.release();
    }
    if (photoSession) {
      photoSession.release();
    }
    if (photoOutPut) {
      photoOutPut.off('photoAssetAvailable');
      photoOutPut.off('captureReady');
      photoOutPut.release();
    }
  } catch (error) {
    hilog.error(DOMAIN, TAG, `The releaseCamera call failed. error: ${error.code}`);
  }
}

// 拍照后将图片保存至媒体库
export function setPhotoOutputCb(photoOutput: camera.PhotoOutput): void {
  photoOutput.on('photoAssetAvailable',
    async (_err: BusinessError, photoAsset: photoAccessHelper.PhotoAsset): Promise<void> => {
      let accessHelper: photoAccessHelper.PhotoAccessHelper =
        photoAccessHelper.getPhotoAccessHelper(currentContext);
      let assetChangeRequest: photoAccessHelper.MediaAssetChangeRequest =
        new photoAccessHelper.MediaAssetChangeRequest(photoAsset);
      try {
        assetChangeRequest.saveCameraPhoto();
        await accessHelper.applyChanges(assetChangeRequest);
        AppStorage.setOrCreate('photoUri', await photoAsset.getThumbnail());
      } catch (error) {
        hilog.error(DOMAIN, TAG, `The setPhotoOutputCb call failed. error: ${error.code}`);
      }
    });
}

在主页面中引入SoundPoolUtil类和CameraShooter类，并在点击拍照时调用SoundPool播放函数：

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import { abilityAccessCtrl, Permissions } from '@kit.AbilityKit';
import { display } from '@kit.ArkUI';
import { hilog } from '@kit.PerformanceAnalysisKit';
import {
  cameraShooting, capture,
} from '../utils/CameraShooter';
import { SoundPoolUtil } from '../utils/SoundPoolUtil';

const DOMAIN: number = 0x0000;
const TAG: string = '[XComponentPage]';

let cameraPosition = 0;
let surfaceId = '';
let storage = new LocalStorage();

@Component
@Entry(storage)
export struct CameraPage {
  mXComponentController: XComponentController = new XComponentController;
  permissions: Array<Permissions> = [
    'ohos.permission.CAMERA',
  ];
  private isFront: boolean = false;
  // 全局context
  private context: Context = this.getUIContext().getHostContext()!;
  private displayWidth = display.getDefaultDisplaySync().width;
  private soundPoolUtil = new SoundPoolUtil(this.context);

  async aboutToAppear() {
    try {
      // 在aboutToAppear页面申请相机权限
      abilityAccessCtrl.createAtManager().requestPermissionsFromUser(this.context, this.permissions).then(() => {
        setTimeout(() => {
          cameraShooting(cameraPosition, surfaceId, this.context);
        }, 200);
      });
    } catch (error) {
      hilog.error(DOMAIN, TAG, `The cameraShooting failed. error: ${JSON.stringify(error)}`);
    }
  }

  build() {
    RelativeContainer() {
      // XComponent主视图
      XComponent({
        type: XComponentType.SURFACE,
        controller: this.mXComponentController
      })
        .onLoad(async () => {
          this.mXComponentController.setXComponentSurfaceRect({
            surfaceWidth: this.displayWidth,
            surfaceHeight: this.displayWidth * 4 / 3
          });
          surfaceId = this.mXComponentController.getXComponentSurfaceId();
        })

      Row() {
        Stack() {
          // 拍照按钮
          Image($r('app.media.capture'))
            .height(70)
            .onClick(() => {
              capture(this.isFront);
              // 播放自定义快门声音
              this.soundPoolUtil?.PlaySoundPool();
            })
        }
      }
      .id('controlPanel')
      .width('100%')
      .justifyContent(FlexAlign.SpaceAround)
      .alignRules({
        bottom: { anchor: '__container__', align: VerticalAlign.Bottom }
      })
      .margin({ bottom: '40vp' })
    }
    .height('100%')
    .backgroundColor(Color.Black)
  }
}

export async function fromBack(context: Context): Promise<void> {
  cameraShooting(cameraPosition, surfaceId, context);
}

打开摄像头后使用DevEco Testing测试功耗，手机温度上升过快

使用折叠屏手机进行相机预览，在展开态时黑屏

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