Use the device's flash unit on Android SDK (Kotlin/Java)

Enabling the device's flash unit during an AR session can help improve visibility.

Check that the current camera configuration supports flash

Not all camera configurations support enabling a flash unit. Before enabling the flash or offering users the option to enable the flash, ensure that the flash unit is available for the active camera configuration:

boolean flashAvailable;
try {
  CameraManager cameraManager =
      (CameraManager) context.getSystemService(Context.CAMERA_SERVICE);

  CameraCharacteristics characteristics =
      cameraManager.getCameraCharacteristics(session.getCameraConfig().getCameraId());
  flashAvailable = characteristics.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
} catch (Exception e) {
  flashAvailable = false;
}

val flashAvailable =
  runCatching {
      val cameraManager = context.getSystemService(Context.CAMERA_SERVICE) as CameraManager
      val characteristics = cameraManager.getCameraCharacteristics(session.cameraConfig.cameraId)
      characteristics.get(CameraCharacteristics.FLASH_INFO_AVAILABLE)
    }
    .getOrNull() ?: false

Enable the flash unit

Enable the flash unit by configuring the AR session with Config.FlashMode.TORCH:

if (flashAvailable) {
  Config config = session.getConfig();
  config.setFlashMode(Config.FlashMode.TORCH);
  session.configure(config);
}

if (flashAvailable) {
  session.configure(session.config.apply { flashMode = Config.FlashMode.TORCH })
}

Disable the flash unit

Disable the flash unit by configuring the AR session with Config.FlashMode.OFF:

Config config = session.getConfig();
config.setFlashMode(Config.FlashMode.OFF);
session.configure(config);

session.configure(session.config.apply { flashMode = Config.FlashMode.OFF })