Android SurfaceView预览版太暗

我正在开发使用Surfaceview的应用程序.我可以拍照，一切都很好.

I'm developing an App that uses Surfaceview. I can take pictures and everything's fine.

我的问题是:预览图像太暗.我尝试更改相机的SceneMode，但没有任何效果(我尝试了AUTO，NIGHT和NIGHT_PORTRAIT).

My problem is: the image of the preview is too dark. I try to change the SceneMode of the camera, but nothing is working (I've tried AUTO, NIGHT and NIGHT_PORTRAIT).

以下是使用我的应用拍摄的照片之间的区别:

Here is the difference between pictures taken with my app:

和Android Camera App(本机):

and the Android Camera App (native):

这是我的代码(凸轮上使用的参数):

Here's my code (the params used on cam):

        c = Camera.open(0);
        Camera.Parameters params =  c.getParameters();
        params.setSceneMode(Camera.Parameters.SCENE_MODE_NIGHT);
        params.setAutoExposureLock(true);
        params.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
        if (params.getMaxNumMeteringAreas() > 0){ // check that metering areas are supported
            List<Camera.Area> meteringAreas = new ArrayList<>();
            Rect areaRect1 = new Rect(-100, -100, 100, 100);    // specify an area in center of image
            meteringAreas.add(new Camera.Area(areaRect1, 600)); // set weight to 60%
            Rect areaRect2 = new Rect(800, -1000, 1000, -800);  // specify an area in upper right of image
            meteringAreas.add(new Camera.Area(areaRect2, 400)); // set weight to 40%
            params.setMeteringAreas(meteringAreas);
        }
        c.setParameters(params);

有人可以帮助我吗?

谢谢！