【HarmonyOS实战开发】鸿蒙相机开发最佳实践

拍照实现方案(ArkTS)

当前示例提供完整的拍照流程介绍，方便开发者了解完整的接口调用顺序。

在参考以下示例前，建议开发者查看相机开发指导(ArkTS)的具体章节，了解设备输入、会话管理、拍照单个流程。

开发流程

在获取到相机支持的输出流能力后，开始创建拍照流，开发流程如下。

完整示例

Context获取方式请参考：获取UIAbility的上下文信息。

import { camera } from '@kit.CameraKit';
import { image } from '@kit.ImageKit';
import { BusinessError } from '@kit.BasicServicesKit';
import { common } from '@kit.AbilityKit';
import { fileIo as fs } from '@kit.CoreFileKit';
import { photoAccessHelper } from '@kit.MediaLibraryKit';

let context = getContext(this);

async function savePicture(buffer: ArrayBuffer, img: image.Image): Promise<void> {
  let accessHelper: photoAccessHelper.PhotoAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
  let options: photoAccessHelper.CreateOptions = {
    title: Date.now().toString()
  };
  let photoUri: string = await accessHelper.createAsset(photoAccessHelper.PhotoType.IMAGE, 'jpg', options);
  //createAsset的调用需要ohos.permission.READ_IMAGEVIDEO和ohos.permission.WRITE_IMAGEVIDEO的权限
  let file: fs.File = fs.openSync(photoUri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
  await fs.write(file.fd, buffer);
  fs.closeSync(file);
  img.release(); 
}

function setPhotoOutputCb(photoOutput: camera.PhotoOutput): void {
  //设置回调之后，调用photoOutput的capture方法，就会将拍照的buffer回传到回调中
  photoOutput.on('photoAvailable', (errCode: BusinessError, photo: camera.Photo): void => {
    console.info('getPhoto start');
    console.info(`err: ${JSON.stringify(errCode)}`);
    if (errCode || photo === undefined) {
      console.error('getPhoto failed');
      return;
    }
    let imageObj = photo.main;
    imageObj.getComponent(image.ComponentType.JPEG, (errCode: BusinessError, component: image.Component): void => {
      console.info('getComponent start');
      if (errCode || component === undefined) {
        console.error('getComponent failed');
        return;
      }
      let buffer: ArrayBuffer;
      if (component.byteBuffer) {
        buffer = component.byteBuffer;
      } else {
        console.error('byteBuffer is null');
        return;
      }
      savePicture(buffer, imageObj);
    });
  });
}

async function cameraShootingCase(baseContext: common.BaseContext, surfaceId: string): Promise<void> {
  // 创建CameraManager对象
  let cameraManager: camera.CameraManager = camera.getCameraManager(baseContext);
  if (!cameraManager) {
    console.error("camera.getCameraManager error");
    return;
  }
  // 监听相机状态变化
  cameraManager.on('cameraStatus', (err: BusinessError, cameraStatusInfo: camera.CameraStatusInfo) => {
    if (err !== undefined && err.code !== 0) {
      console.error('cameraStatus with errorCode = ' + err.code);
      return;
    }
    console.info(`camera : ${cameraStatusInfo.camera.cameraId}`);
    console.info(`status: ${cameraStatusInfo.status}`);
  });

  // 获取相机列表
  let cameraArray: Array<camera.CameraDevice> = cameraManager.getSupportedCameras();
  if (cameraArray.length <= 0) {
    console.error("cameraManager.getSupportedCameras error");
    return;
  }

  for (let index = 0; index < cameraArray.length; index++) {
    console.info('cameraId : ' + cameraArray[index].cameraId);                          // 获取相机ID
    console.info('cameraPosition : ' + cameraArray[index].cameraPosition);              // 获取相机位置
    console.info('cameraType : ' + cameraArray[index].cameraType);                      // 获取相机类型
    console.info('connectionType : ' + cameraArray[index].connectionType);              // 获取相机连接类型
  }

  // 创建相机输入流
  let cameraInput: camera.CameraInput | undefined = undefined;
  try {
    cameraInput = cameraManager.createCameraInput(cameraArray[0]);
  } catch (error) {
    let err = error as BusinessError;
    console.error('Failed to createCameraInput errorCode = ' + err.code);
  }
  if (cameraInput === undefined) {
    return;
  }

  // 监听cameraInput错误信息
  let cameraDevice: camera.CameraDevice = cameraArray[0];
  cameraInput.on('error', cameraDevice, (error: BusinessError) => {
    console.error(`Camera input error code: ${error.code}`);
  })

  // 打开相机
  await cameraInput.open();

  // 获取支持的模式类型
  let sceneModes: Array<camera.SceneMode> = cameraManager.getSupportedSceneModes(cameraArray[0]);
  let isSupportPhotoMode: boolean = sceneModes.indexOf(camera.SceneMode.NORMAL_PHOTO) >= 0;
  if (!isSupportPhotoMode) {
    console.error('photo mode not support');
    return;
  }
  // 获取相机设备支持的输出流能力
  let cameraOutputCap: camera.CameraOutputCapability = cameraManager.getSupportedOutputCapability(cameraArray[0], camera.SceneMode.NORMAL_PHOTO);
  if (!cameraOutputCap) {
    console.error("cameraManager.getSupportedOutputCapability error");
    return;
  }
  console.info("outputCapability: " + JSON.stringify(cameraOutputCap));

  let previewProfilesArray: Array<camera.Profile> = cameraOutputCap.previewProfiles;
  if (!previewProfilesArray) {
    console.error("createOutput previewProfilesArray == null || undefined");
  }

  let photoProfilesArray: Array<camera.Profile> = cameraOutputCap.photoProfiles;
  if (!photoProfilesArray) {
    console.error("createOutput photoProfilesArray == null || undefined");
  }

  // 创建预览输出流,其中参数 surfaceId 参考上文 XComponent 组件，预览流为XComponent组件提供的surface
  let previewOutput: camera.PreviewOutput | undefined = undefined;
  try {
    previewOutput = cameraManager.createPreviewOutput(previewProfilesArray[0], surfaceId);
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to create the PreviewOutput instance. error code: ${err.code}`);
  }
  if (previewOutput === undefined) {
    return;
  }
  // 监听预览输出错误信息
  previewOutput.on('error', (error: BusinessError) => {
    console.error(`Preview output error code: ${error.code}`);
  });

  // 创建拍照输出流
  let photoOutput: camera.PhotoOutput | undefined = undefined;
  try {
    photoOutput = cameraManager.createPhotoOutput(photoProfilesArray[0]);
  } catch (error) {
    let err = error as BusinessError;
    console.error('Failed to createPhotoOutput errorCode = ' + err.code);
  }
  if (photoOutput === undefined) {
    return;
  }

    //调用上面的回调函数来保存图片
  setPhotoOutputCb(photoOutput);

  //创建会话
  let photoSession: camera.PhotoSession | undefined = undefined;
  try {
    photoSession = cameraManager.createSession(camera.SceneMode.NORMAL_PHOTO) as camera.PhotoSession;
  } catch (error) {
    let err = error as BusinessError;
    console.error('Failed to create the session instance. errorCode = ' + err.code);
  }
  if (photoSession === undefined) {
    return;
  }
  // 监听session错误信息
  photoSession.on('error', (error: BusinessError) => {
    console.error(`Capture session error code: ${error.code}`);
  });

  // 开始配置会话
  try {
    photoSession.beginConfig();
  } catch (error) {
    let err = error as BusinessError;
    console.error('Failed to beginConfig. errorCode = ' + err.code);
  }

  // 向会话中添加相机输入流
  try {
    photoSession.addInput(cameraInput);
  } catch (error) {
    let err = error as BusinessError;
    console.error('Failed to addInput. errorCode = ' + err.code);
  }

  // 向会话中添加预览输出流
  try {
    photoSession.addOutput(previewOutput);
  } catch (error) {
    let err = error as B