@Override
        public void onError(@NonNull CameraPickerHelper helper) {
            AbsBoxingViewFragment fragment = mWr.get();
            if (fragment == null) {
                return;
            }
            fragment.onCameraError();
        }
start camera to take a photo.

@param activity      the caller activity.
@param fragment      the caller fragment, may be null.
@param subFolderPath the folder name in "DCIM/bili/boxing/"
boxing/src/main/java/com/bilibili/boxing/AbsBoxingViewFragment.java