Using the Flashlight (C++)

To use the flashlight mode, you manipulate your phone to turn on the flashlight, which then stays on persistently.

When you use the flashlight mode with a camera application, the following situations may occur:

• When the rear camera is used and Camera_FlashMode is set to off, the flashlight cannot be turned on.
• When the front camera is used, the flashlight can be turned on and remains steady on.
• When you switch from the front camera to the rear camera, the flashlight will be automatically turned off if it was turned on previously.

How to Develop

Read Camera for the API reference.

1. Import the NDK.

    // Include the NDK header files.
    #include "hilog/log.h"
    #include "ohcamera/camera.h"
    #include "ohcamera/camera_input.h"
    #include "ohcamera/capture_session.h"
    #include "ohcamera/camera_manager.h"
   

2. Link the dynamic library in the CMake script.

    target_link_libraies(entry PUBLIC libohcamera.so libhilog_ndk.z.so)
   

3. Call OH_CameraManager_IsTorchSupported() to check whether the current device supports the flashlight.

   // Check whether the device supports the flashlight.
   Camera_OutputCapability* cameraOutputCapability = nullptr;
   Camera_TorchMode torchMode = AUTO;
   bool isTorchSupported = false;
   Camera_ErrorCode ret = OH_CameraManager_IsTorchSupported(cameraManager, &isTorchSupported);
   if (cameraManager == nullptr || ret != CAMERA_OK) {
       OH_LOG_ERROR(LOG_APP, "OH_CameraManager_IsTorchSupported failed.");
   }
   if (isTorchSupported) {
       OH_LOG_INFO(LOG_APP, "isTorchSupported success.");
   } else {
       OH_LOG_ERROR(LOG_APP, "isTorchSupported failed.");
   }
   

4. Call OH_CameraManager_IsTorchSupportedByTorchMode() to check whether the current device supports a specific flashlight mode.

   bool torchModeSupported = false;
   ret = OH_CameraManager_IsTorchSupportedByTorchMode(cameraManager, torchMode, &torchModeSupported);
   if (cameraManager == nullptr || ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CameraManager_IsTorchSupported failed.");
   }
   if (torchModeSupported) {
        OH_LOG_INFO(LOG_APP, "isTorchModeSupported success.");
   } else {
        OH_LOG_ERROR(LOG_APP, "isTorchModeSupported failed. %{public}d ", ret);
   }
   

5. Call OH_CameraManager_SetTorchMode() to set the flashlight mode.

   if (torchModeSupported) {
      OH_LOG_INFO(LOG_APP, "OH_CameraManager_IsTorchModeSupported success.");
      // Set the flashlight mode.
      ret = OH_CameraManager_SetTorchMode(cameraManager, torchMode);
      if (ret != CAMERA_OK) {
          OH_LOG_ERROR(LOG_APP, "OH_CameraManager_SetTorchMode failed. %{public}d ", ret);
      } else {
          OH_LOG_INFO(LOG_APP, "OH_CameraManager_SetTorchMode success.");
        }
   } else {
      OH_LOG_ERROR(LOG_APP, "OH_CameraManager_IsTorchModeSupported failed.");
   }
   

Status Listening

During camera application development, you can listen for changes of the flashlight status, including on, off, unavailable, and available, by using the callback function.

Register the torchStatus event and return the listening result through a callback, which carries the Camera_TorchStatusInfo parameter. For details about the parameter, see Camera_TorchStatusInfo.

ret = OH_CameraManager_RegisterTorchStatusCallback(cameraManager, GetTorchStatusCallback);
if (ret != CAMERA_OK) {
   OH_LOG_ERROR(LOG_APP, "OH_CameraManager_RegisterTorchStatusCallback failed.");
}

void GetTorchStatusCallback(Camera_Manager *cameraManager, Camera_TorchStatusInfo* torchStatus)
{
   OH_LOG_INFO(LOG_APP, "OH_CameraManager_GetTorchStatusCallback is called.");
}