HarmonyOS开发中如何控制打开和关闭手电筒？

Question

关于相机，在创建预览输出流后，点击页面上的某个icon或button，toggle手电筒的开启和关闭。该功能不受拍照功能的影响（即和是否创建拍照输出流无关）。

Answer 1

参考代码如下：

// 封装一个相机预览管控类 
class CameraManagerWrapper { 
  private mCameraManager?: camera.CameraManager; // 相机控制器 
  private mCameraDevices?: Array<camera.CameraDevice>; // 设备列表 
  private mCameraInput?: camera.CameraInput; 
  private mPreviewOutput?: camera.PreviewOutput; 
  private mVideoSession?: camera.VideoSession; // 会话 
  /** 
   * 开启回话，这里只是配置一个预览流，用于测试功能 
   * @param surfaceId 
   */ 
  public async doPreview(surfaceId: string) { 
    this.mCameraManager = getCameraManager(getContext(this)); 
    this.mCameraDevices = getCameraDevices(this.mCameraManager as camera.CameraManager) 
    let profiles = this.mCameraManager.getSupportedOutputCapability(this.mCameraDevices[0]); // 获取对应相机设备profiles 
    // 创建 预览流1 输出对象 
    this.mPreviewOutput = this.mCameraManager.createPreviewOutput(profiles.previewProfiles[0], surfaceId); 
    // 创建cameraInput对象 
    this.mCameraInput = this.mCameraManager.createCameraInput(this.mCameraDevices[0]); 
    // 打开相机 
    await this.mCameraInput.open(); 
    // 会话流程 
    this.mVideoSession = this.mCameraManager.createSession(camera.SceneMode.NORMAL_VIDEO) as camera.VideoSession; 
    // 开始配置会话 
    this.mVideoSession.beginConfig(); 
    // 把CameraInput加入到会话 
    this.mVideoSession.addInput(this.mCameraInput); 
    // 把 预览流1 加入到会话 
    this.mVideoSession.addOutput(this.mPreviewOutput); 
    // 提交配置信息 
    await this.mVideoSession.commitConfig(); 
    // 会话开始 
    await this.mVideoSession.start(); 
  } 
  public doFlash(isOpen: boolean) { 
    // 支持闪光灯 
    let hasFlash = this.mVideoSession?.hasFlash(); 
    if (!hasFlash) { 
      return; 
    } 
    console.info('hasFlash --> setFlashMode: ' + isOpen) 
    this.mVideoSession?.setFlashMode(isOpen ? camera.FlashMode.FLASH_MODE_ALWAYS_OPEN : camera.FlashMode.FLASH_MODE_CLOSE); 
  } 
  public doRelease() { 
    this.mVideoSession?.stop(); 
    this.mCameraInput?.close(); 
    this.mPreviewOutput?.release(); 
    if (this.mVideoSession) { 
      this.mVideoSession.release(); 
      this.mVideoSession = undefined; 
    } 
  } 
} 
private mCameraManagerWrapper?: CameraManagerWrapper; 
@Builder 
PreviewManage() { 
  Column() { 
    CustomButton({ mTitle: '实现相机预览' }).onClick(async () => { 
      this.mCameraManagerWrapper = new CameraManagerWrapper(); 
      this.mCameraManagerWrapper.doPreview(this.surfaceId); 
    }) 
 
    CustomButton({ mTitle: '开启闪光灯' }).onClick(() => { 
      this.mCameraManagerWrapper?.doFlash(true); 
    }) 
 
    CustomButton({ mTitle: '关闭闪光灯' }).onClick(() => { 
      this.mCameraManagerWrapper?.doFlash(false); 
    }) 
  } 
  .borderWidth(2) 
  .borderColor(0xff00ff00) 
}