摄像头前后摄设定方法，目前有定义值两个分别为CAMERA_FACING_FRONT前置和CAMERA_FACING_BACK后置，摄像头个数int cameraCount = Camera.getNumberOfCameras();

摄像头个数：

int cameraCount = Camera.getNumberOfCameras();

cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK 后摄

cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT 前摄