Android前置摄像头

以下是两种在Android程序中调用前置摄像头的方法：
1. 使用Camera2 API

// 获取CameraManager实例
CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
try {
    // 获取可用摄像头列表
    String[] cameraIds = cameraManager.getCameraIdList();
    for (String cameraId : cameraIds) {
        // 获取相机的相关参数
        CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(cameraId);
        Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING);
        if (facing != null && facing == CameraCharacteristics.LENS_FACING_FRONT) {
            // 打开前置摄像头
            cameraManager.openCamera(cameraId, new CameraDevice.StateCallback() {
                @Override
                public void onOpened(@NonNull CameraDevice camera) {
                    // 摄像头打开成功后的操作
                }

                @Override
                public void onDisconnected(@NonNull CameraDevice camera) {
                    // 摄像头断开连接后的操作
                }

                @Override
                public void onError(@NonNull CameraDevice camera, int error) {
                    // 摄像头打开失败后的操作
                }
            }, null);
            break;
        }
    }
} catch (CameraAccessException e) {
    e.printStackTrace();
}

2. 使用Camera框架

// 获取前置摄像头的ID
int cameraId = -1;
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
for (int i = 0; i < Camera.getNumberOfCameras(); i++) {
    Camera.getCameraInfo(i, cameraInfo);
    if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
        cameraId = i;
        break;
    }
}
// 打开前置摄像头
Camera camera = Camera.open(cameraId);