在自定义相机中，连续两次调用拍照方法，会出现如下报错：
CameraService, start capture picture 1 CameraService, start capture picture 2 CameraService, capture callback 1 err: undefined SendRequest 168: failed, handle:31 error:13 desc:IStreamCapture proxy:3130119360 time:230783611856317 {Capture():42} HStreamCaptureProxy Capture failed, error: 13 {Capture():602} PhotoOutput Failed to Capture!, errCode: 13 CameraService, capture callback 2 err: {"code":"7400102","message":""}
连续两次调用拍照方法的核心代码如下：
Logger.error(TAG, 'start capture picture 1'); this.photoOutput?.capture(photoSettings, (err) => { Logger.error(TAG, `capture callback 1 err: ${err}`); }); Logger.error(TAG, 'start capture picture 2'); this.photoOutput?.capture(photoSettings, (err) => { Logger.error(TAG, `capture callback 2 err: ${err}`); });
错误码7400102表示接口执行顺序错误，可以发现在代码中第二次调用capture方法时，并不能确保第一次的capture方法已经执行完毕，报错原因为两次方法同时执行造成了冲突。
如需多次调用capture方法，可以对拍照输出流注册on('captureReady')监听，监听到上一次拍摄完成时再异步调用capture方法，并当拍摄次数达到规定次数后取消监听：
import { camera } from '@kit.CameraKit'; import { BusinessError, emitter } from '@kit.BasicServicesKit'; import { photoAccessHelper } from '@kit.MediaLibraryKit'; import { common } from '@kit.AbilityKit'; import { colorSpaceManager } from '@kit.ArkGraphics2D'; 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; let uri: string; export async function cameraShooting(cameraPosition: number, surfaceId: string, context: Context): Promise<void> { currentContext = context; releaseCamera(); try { // 获取相机管理器对象 let cameraManager: camera.CameraManager = camera.getCameraManager(context); let cameraArray: camera.CameraDevice[] = cameraManager.getSupportedCameras(); if (cameraArray.length <= 0) { 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) { return; } if (!cameraOutputCap) { return; } // 获取预览流的Profile列表 let previewProfilesArray: camera.Profile[] = cameraOutputCap.previewProfiles; // 选择合适的预览流分辨率，可以手动选取或通过代码选取 let previewProfile: camera.Profile | undefined = undefined; for (let i = previewProfilesArray.length - 1; i >= 0; i--) { if (previewProfilesArray[i].size.width / previewProfilesArray[i].size.height === 4 / 3) { previewProfile = previewProfilesArray[i]; break; } } // 创建预览输出流，surfaceId为显示组件的id previewOutput = cameraManager.createPreviewOutput(previewProfile, surfaceId); // 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; }); } if (previewOutput === undefined) { return; } // 创建拍照输出流 photoOutPut = cameraManager.createPhotoOutput(photoProfile); if (photoOutPut === undefined) { return; } // 将图片保存至媒体库 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)}`); } } // 拍照函数 export async function capture(isFront: boolean) { try { // 拍照输出设置 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}`); } } // 连拍设置函数 export async function burstCapture(isFront: boolean, captureCount: number) { await capture(isFront); let currCount = 1; photoOutPut.on('captureReady', async () => { await capture(isFront); currCount++; if (currCount >= captureCount) { emitter.emit('burstCaptureOff'); } }); emitter.once('burstCaptureOff', () => { photoOutPut.off('captureReady'); }); } // 相机相关资源释放 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) { emitter.off('burstCaptureOff'); photoOutPut.off('photoAssetAvailable'); photoOutPut.off('captureReady'); photoOutPut.release(); } } catch (error) { hilog.error(DOMAIN, TAG, `The releaseCamera call failed. error: ${error.code}`); } } // 将拍照图片保存至媒体库 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); uri = photoAsset.uri; AppStorage.setOrCreate('photoUri', await photoAsset.getThumbnail()); } catch (error) { hilog.error(DOMAIN, TAG, `The setPhotoOutputCb call failed. error: ${error.code}`); } }); } // 预览照片 export function previewPhoto(context: Context): void { let photoContext = context as common.UIAbilityContext; photoContext.startAbility({ parameters: { uri: uri }, action: 'ohos.want.action.viewData', bundleName: 'com.huawei.hmos.photos', abilityName: 'com.huawei.hmos.photos.MainAbility' }, (err: BusinessError) => { hilog.error(DOMAIN, TAG, `The previewPhoto call failed. error: ${err.code}`); }); }
主页面的代码示例参考如下：
import { dataSharePredicates } from '@kit.ArkData'; import { abilityAccessCtrl, Permissions } from '@kit.AbilityKit'; import { camera } from '@kit.CameraKit'; import { photoAccessHelper } from '@kit.MediaLibraryKit'; import { filePreview } from '@kit.PreviewKit'; import { curves, display } from '@kit.ArkUI'; import { hilog } from '@kit.PerformanceAnalysisKit'; import { cameraShooting, burstCapture, previewPhoto, } from '../utils/CameraShooter'; const DOMAIN: number = 0x0000; const TAG: string = '[XComponentPage]'; let cameraPosition = 0; let surfaceId = ''; let storage = new LocalStorage(); // 需要连续拍摄的照片个数 let picturesTaken: number = 3; // 设备显示屏的宽度 let displayWidth: number = display.getDefaultDisplaySync().width; @Component @Entry(storage) export struct Index { @StorageLink('photoUri') photoUri: string | Resource | PixelMap = ''; @State context: Context = this.getUIContext().getHostContext()!; mXComponentController: XComponentController = new XComponentController; permissions: Array<Permissions> = [ 'ohos.permission.CAMERA', ]; private isFront: boolean = false; onPageShow(): void { filePreview.closePreview(this.context); } async aboutToAppear() { try { abilityAccessCtrl.createAtManager().requestPermissionsFromUser(this.context, this.permissions).then(() => { setTimeout(async () => { cameraShooting(cameraPosition, surfaceId, this.context); }, 200); }); } catch (error) { hilog.error(DOMAIN, TAG, `The updatePreview call failed. error: ${JSON.stringify(error)}`); } } build() { RelativeContainer() { // 主视图页面 XComponent({ type: XComponentType.SURFACE, controller: this.mXComponentController }) .onLoad(async () => { this.mXComponentController.setXComponentSurfaceRotation({ lock: true }); this.mXComponentController.setXComponentSurfaceRect({ surfaceWidth: displayWidth, surfaceHeight: displayWidth * 4 / 3 }); surfaceId = this.mXComponentController.getXComponentSurfaceId(); }) // 拍摄完后显示缩略图 Row() { Image(this.photoUri) .borderWidth(this.photoUri === '' ? 0 : 1) .borderColor(Color.White) .height(50) .width(50) .borderRadius(25) .animation({ curve: curves.springMotion() }) .onClick(() => { if (this.photoUri !== '') { previewPhoto(this.context); } }) Image($r('app.media.capture')) .height(50) .onClick(() => { // isFront为是否摄像头是否前置，picturesTaken为连续调用capture的次数 burstCapture(this.isFront, picturesTaken); }) // 前后摄像头切换 Image($r('app.media.switch_camera')) .height(50) .animation({ curve: curves.springMotion() }) .onClick(async () => { cameraPosition = cameraPosition === camera.CameraPosition.CAMERA_POSITION_BACK ? camera.CameraPosition.CAMERA_POSITION_UNSPECIFIED : camera.CameraPosition.CAMERA_POSITION_BACK; cameraShooting(cameraPosition, surfaceId, this.context); }) } .id('controlPanel') .width('100%') .justifyContent(FlexAlign.SpaceAround) .alignRules({ bottom: { anchor: '__container__', align: VerticalAlign.Bottom } }) .margin({ bottom: '60vp' }) } .height('100%') .backgroundColor('#000000') } // 获取照片的缩略图 async getThumbnail(): Promise<void> { let predicates: dataSharePredicates.DataSharePredicates = new dataSharePredicates.DataSharePredicates(); predicates.orderByDesc(photoAccessHelper.PhotoKeys.DATE_ADDED); let fetchOptions: photoAccessHelper.FetchOptions = { fetchColumns: [], predicates: predicates }; let photoHelper = photoAccessHelper.getPhotoAccessHelper(this.context); try { let fetchResult: photoAccessHelper.FetchResult<photoAccessHelper.PhotoAsset> = await photoHelper.getAssets(fetchOptions); if (fetchResult !== undefined) { let photoAsset: photoAccessHelper.PhotoAsset = await fetchResult.getFirstObject(); this.photoUri = await photoAsset.getThumbnail(); } } catch (error) { hilog.error(DOMAIN, TAG, `The getThumbnail call failed. error: ${JSON.stringify(error)}`); } } } export async function fromBack(context: Context): Promise<void> { cameraShooting(cameraPosition, surfaceId, context); }