"I want to run the sample program ""face-detection"" in-camera + vertical orientation on Android + OpenCV."

I looked for the OpenCV reference and source code, but I want to run it in camera + vertical direction, but I can't do it as the camera preview was intended.
If your smartphone is sideways, the preview is normal.Vertical orientation causes the preview to be upside down.
I would like to use setDisplayOrientation and setRotation upside down, but my program did not work as intended.
Please let me know if you know.

• Eclipse 4.4+ADT
• API19
• Nexus5

What I've tried.
Verified that the CameraBridgeViewBase type of the member variable mOpenCvCameraView works with the JavaCameraView type. ->Verified that it works as intended.

JavaCameraViewCreate a JavaCameraView2 class that inherited the JavaCameraView and add a method to change the orientation

FdActivityIn the class onCreate method, call the created method
->Here we are.

public class JavaCameraView2 extensions JavaCameraView{
    // snip..
    public void setCameraRotation(intangle){
        Log.i(TAG, "called setCameraRotation");

        try{
            This.mCamera.setDisplayOrientation(angle);

        } catch(Exceptione){
            Log.e(TAG, "failed camera setting");
            e.printStackTrace();
        }
    }
}


public class FdActivity extensions Activity implements CvCameraViewListener2 {
    private JavaCameraView 2mOpenCvCameraView;
// snip..
    /** Called when the activity is first created.*/
    @ Override
    public void onCreate (Bundle savedInstanceState) {
        Log.i(TAG, "called onCreate");
        super.onCreate(savedInstanceState);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

        setContentView(R.layout.face_detect_surface_view);

        mOpenCvCameraView=(JavaCameraView2) findViewById(R.id.fd_activity_surface_view);
        mOpenCvCameraView.setCvCameraViewListener(this);
        mOpenCvCameraView.setCameraRotation(90);
    }
// snip..
}

mOpenCvCameraView.setCameraRotation(90); generates Java.lang.NullPointerException.

Thank you for your cooperation.

Additional
Based on your advice, I added code to the "onResume" method.

public void onResume(){
  super.onResume();

  OpenCVLoader.initAsync (OpenCVLoader.OPENCV_VERSION_2_4_3, this, mLoaderCallback);
  // Additional hereinafter
  mOpenCvCameraView.setVisibility (SurfaceView.VISIBLE);
  mOpenCvCameraView.setCameraRotation(90);
  mOpenCvCameraView.enableView();
}

The result was a NullPointerException and did not work as intended.
Please let me know if you have any information to help me.

1/27 Additional
I was able to set the preview in the intended direction.Please refer to the following site.
OpenCV4 Android-Displaying Preview in Portrait Mode

Immediately after opening the camera, the setDisplayOrientation method does not change its orientation. I think OpenCV has been coded so that I can't change the orientation, so I adjusted the orientation on the reference site
I did.
However, if you keep doing this, the ratio will not be correct, so it will be previewed in a crushed state.
I am not sure if this method is correct.

Now, I'm adjusting the ratio so that it doesn't collapse.

public class FdActivity extensions Activity implements CvCameraViewListener2{
    private MatmRgbaF;
    private MatmRgbaT;

    public void onCameraViewStarted(int width, int height) {
        mGray = new Mat();
        mRgba = new Mat();

        mRgbaF = new Mat(height, width, CvType.CV_8UC4);
        mRgbaT = new Mat (width, width, CvType.CV_8UC4);
    }

    public MatonCameraFrame (CvCameraViewFrame inputFrame) {
        // omission

        // Rotate mRgba90 degrees
        Core.transpose (mRgba, mRgbaT);
        Imgproc.resize(mRgbaT, mRgbaF, mRgbaF.size(), 0, 0);
        Core.flip(mRgbaF,mRgba,0);

        return mRgba;
    }

}

If you have any information other than this method, please let me know.
Thank you for your cooperation.

Note 2/9
With the above method, the preview screen was crushed (the ratio of vertical to horizontal is strange), and it didn't work out as intended, so I was looking for a website that I could refer to.
I checked the following site and confirmed that the back camera + portrait will work as intended, but the preview screen will be upside down with the in-camera + portrait.

Reference Site:
http://answers.opencv.org/question/7313/rotating-android-camera-to-portrait/
http://littlecheesecake.me/blog/13804736/opencv-android-orientation

In conclusion, OpenCV cannot operate as intended under "in-camera + portrait" conditions.I have determined that
Thank you.