配置相机的输入流和输出流。相机在拍摄前，必须完成输入输出流的配置。

配置输入流即添加设备输入，对用户而言，相当于选择设备的某一相机拍摄；配置输出流，即选择数据将以什么形式输出。当应用需要实现拍照时，输出流应配置为预览流和拍照流，预览流的数据将显示在XComponent组件上，拍照流的数据将通过ImageReceiver接口的能力保存到相册中。
添加闪光灯、调整焦距等配置。具体支持的配置及接口说明请参考@ohos.multimedia.camera (相机管理)。
会话切换控制。应用可以通过移除和添加输出流的方式，切换相机模式。如当前会话的输出流为拍照流，应用可以将拍照流移除，然后添加视频流作为输出流，即完成了拍照到录像的切换。

完成会话配置后，应用提交和开启会话，可以开始调用相机相关功能。

开发步骤

导入相关接口，导入方法如下。

import { camera } from '@kit.CameraKit';
import { BusinessError } from '@kit.BasicServicesKit';

调用cameraManager中的createSession方法创建一个会话。

// 此处以videoSession为例。
function getSession(cameraManager: camera.CameraManager): camera.VideoSession | undefined {
  let videoSession: camera.VideoSession | undefined = undefined;
  try {
    videoSession = cameraManager.createSession(camera.SceneMode.NORMAL_VIDEO) as camera.VideoSession;
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to create the session instance. error: ${err.code}`);
  }
  return videoSession;
}

调用VideoSession中的beginConfig方法配置会话。

function beginConfig(videoSession: camera.VideoSession): void {
  try {
    videoSession.beginConfig();
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to beginConfig. error: ${err.code}`);
  }
}

使能。向会话中添加相机的输入流和输出流，调用addInput添加相机的输入流；调用addOutput添加相机的输出流。以下示例代码以添加预览流previewOutput和拍照流photoOutput为例，即当前模式支持拍照和预览。

调用VideoSession中的commitConfig和start方法提交相关配置，并启动会话。

在调用addOutput添加相机的输出流前，可通过canAddOutput判断当前相机输出流是否可以添加到session中。

相机输入流cameraInput创建流程请参考设备输入，相机预览输出流previewOutput和拍照输出流photoOutput创建流程请分别参考预览和拍照。

async function startSession(videoSession: camera.VideoSession, cameraInput: camera.CameraInput, previewOutput: camera.PreviewOutput, photoOutput: camera.PhotoOutput): Promise<void> {
  try {
    videoSession.addInput(cameraInput);
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to addInput. error: ${err.code}`);
  }
  let canAddPreviewOutput : boolean = false;
  try {
    canAddPreviewOutput = videoSession.canAddOutput(previewOutput);
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to add previewOutput. error: ${err.code}`);
  }
  if (!canAddPreviewOutput) {
    console.error(`Failed to add preview output.`);
    return;
  }
  try {
    videoSession.addOutput(previewOutput);
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to add previewOutput. error: ${err.code}`);
  }
  let canAddPhotoOutput : boolean = false
  try {
    canAddPhotoOutput = videoSession.canAddOutput(photoOutput);
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to add photoOutput error: ${err.code}`);
  }
  if (!canAddPhotoOutput) {
    console.error(`Failed to add photo output.`);
    return;
  }
  try {
    videoSession.addOutput(photoOutput);
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to add photoOutput. error: ${err.code}`);
  }
  try {
    await videoSession.commitConfig();
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to commitConfig. error: ${err.code}`);
   return;
  }

  try {
    await videoSession.start();
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to start. error: ${err.code}`);
  }
}

会话控制。调用VideoSession中的stop方法可以停止当前会话。调用removeOutput和addOutput方法可以完成会话切换控制。以下示例代码以移除拍照流photoOutput，添加视频流videoOutput为例，完成了拍照到录像的切换。

async function switchOutput(videoSession: camera.VideoSession, videoOutput: camera.VideoOutput, photoOutput: camera.PhotoOutput): Promise<void> {
  try {
    await videoSession.stop();
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to stop. error: ${err.code}`);
  }

  try {
    videoSession.beginConfig();
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to beginConfig. error: ${err.code}`);
  }
  // 从会话中移除拍照输出流。
  try {
    videoSession.removeOutput(photoOutput);
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to remove photoOutput. error: ${err.code}`);
  }
  try {
    videoSession.canAddOutput(videoOutput);
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to add videoOutput error: ${err.code}`);
  }
  // 向会话中添加视频输出流。
  try {
    videoSession.addOutput(videoOutput);
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to add videoOutput. error: ${err.code}`);
  }
  try {
    await videoSession.commitConfig();
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to commitConfig. error: ${err.code}`);
  }

  try {
    await videoSession.start();
  } catch (error) {
    let err = error as BusinessError;
    console.error(`Failed to start. error: ${err.code}`);
  }
}

目录

会话管理(ArkTS)

开发步骤