Adapt camera view with Surfaceview dimension

Question

I'm developing an application where I read some barcode. In a first step I had a big SurfaceView where I can see well the camera preview, but now I would set the dimensions of Surfaceview like the dimensions of barcode but I have bad camera visualization (it is too small). Can someone help me to stretch camera preview? Thanks

Here manage detector and surfaceview:

public class LettoreBarcode extends Fragment {

View view;
SurfaceView surfaceView;
Handler handler;

private BarcodeDetector detector;       
private CameraSource cameraSource;       
private TextView code;
SparseArray<Barcode> items;


private static Button btnBack;

String barcode = "" ;
SparseArray<Articoli> groups = new SparseArray<Articoli>();

Context _context = null;
ProductsAdapter.ViewHolder _ViewHolder = null;

public LettoreBarcode(){

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    view = inflater.inflate(R.layout.fragment_barcode_scanner, container, false);

   surfaceView = (SurfaceView) view.findViewById(R.id.surfaceView);        

    detector = new BarcodeDetector.Builder(getActivity()).setBarcodeFormats(Barcode.ALL_FORMATS).build();   
    final Dialog d = new Dialog(getActivity());
    btnBack = (Button) view.findViewById(R.id.btnBack);
    handler = new Handler();

    if(!detector.isOperational()){
        Toast.makeText(getActivity(), "Detector non attivabile", Toast.LENGTH_LONG).show();
    }

    cameraSource = new CameraSource.Builder(getActivity(), detector).setAutoFocusEnabled(true).build();        


    surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            AttivaCamera();
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {

        }
    });

    detector.setProcessor(new Detector.Processor<Barcode>() {
        @Override
        public void release() {

        }

        @Override
        public void receiveDetections(Detector.Detections<Barcode> detections) {       
            items = detections.getDetectedItems();           
            if (items.size() > 0){      
               getActivity().runOnUiThread(new Runnable() {      
                    @Override
                    public void run() {

                        if (items.valueAt(0) != null){                               
                            //do something

                            handler.postDelayed(new Runnable() {
                                @Override
                                public void run() {
                                    DisattivaCamera();

                                }
                            },10);            //1000
                        }else
                        {
                            d.setContentView(R.layout.dialog_barcode_assente);
                            d.setTitle("Scanner");
                            d.setCancelable(true);
                            d.show();
                            DisattivaCamera();
                        }
                    }
                });

            }
        }

    });

    btnBack.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            getActivity().onBackPressed();
        }
    });

   return view;
}

private void AttivaCamera()
{
    try{
        cameraSource.start(surfaceView.getHolder());    
    }catch(IOException e){
        Toast.makeText(getActivity(), "Errore nell'avvio della fotocamera", Toast.LENGTH_LONG).show();
    }
}

private void DisattivaCamera()
{       
    cameraSource.stop(); 
}

}

It is how I visualize camera with small surfaceview:

https://i.sstatic.net/TMunJ.png

I'm new in android development so I'm sorry if could be a lot of mistake in the code.

Sorry for my english also..

Thanks you guys!

Answer 1

In order to display only part of the camera input, i.e. to crop it on the screen, you need a surface view that has dimensions that fit the camera frame aspect ratio, and overlay it with some nontransparent views to leave only part of it visible. Don't put the SurfaeView inside scrolling layout:

So, instead of

<SurfaceView width: match_parent height: 400dp />

you need e.g. FrameLayout as explained here: Is it possible to crop camera preview?

This will not change the frame that arrives to the barcode detector. But this should not worry you; the detector will handle the uncropped image correctly.