Read QR from fragment and return the result to fragment

Good, I have the following code that works for me when I work with normal activities, the fact is that I am now making an app dependent on fragments, so I do not know how to make this request:

Code to read the qr

scanbtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(PreScan.this, LeerQR.class);
            startActivityForResult(intent, REQUEST_CODE);
        }
    });

This activity receives the values that result from the activity LeerQR.class

  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if(requestCode == REQUEST_CODE && resultCode == RESULT_OK){

        if(data != null){
            final Barcode barcode = data.getParcelableExtra("barcode");
            result.post(new Runnable() {
                @Override
                public void run() {
                    result.setText(barcode.displayValue);

Now, from leerQR send me the answer to my activity back:

     @Override
        public void receiveDetections(Detector.Detections<Barcode> detections) {
            final SparseArray<Barcode> barcodes =  detections.getDetectedItems();
            if(barcodes.size() > 0){
                Intent intent = new Intent();
                //String [] variables = barcodes.split(=);
                intent.putExtra("barcode", barcodes.valueAt(0));
                setResult(RESULT_OK, intent);
                finish();
            }
        }

The question is, how can I do all this with fragment, how can I call the next activity (which is a fragment) and have the result returned to me in such a way that I can use it as it is already programmed in the activity.

Edit, this is my preScan fragment:

    public class PreScan extends Fragment {
Button btnscan;
RequestQueue requestQueue;
TextView result;
String montooper, comCorreo;
public static final int REQUEST_CODE = 100;
public static final int PERMISSION_REQUEST = 200;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view = inflater.inflate(R.layout.fragment_pre_scan, container, false);
    btnscan = (Button)view.findViewById(R.id.btn_scanear);
    requestQueue = Volley.newRequestQueue(getActivity());
    if(ContextCompat.checkSelfPermission(getActivity(), android.Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED){
        ActivityCompat.requestPermissions(getActivity(), new String[]{android.Manifest.permission.CAMERA}, PERMISSION_REQUEST);
    }
    btnscan.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
           //Esto es lo que debo pasar al siguiente fragment, y recibir la respuesta para poder procesarla
           // Intent intent = new Intent(PreScan.this, LeerQR.class);
           // startActivityForResult(intent, REQUEST_CODE);
        }
    });
    return view;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if(requestCode == REQUEST_CODE && resultCode == RESULT_OK){

        if(data != null){
            final Barcode barcode = data.getParcelableExtra("barcode");
            result.post(new Runnable() {
                @Override
                public void run() {
                    result.setText(barcode.displayValue);
                    //aqui proceso el resultado. en una actividad funciona sin problema, aqui no, ya que no se como hacer con los fragments    

                }
            });
        }
    }
}

}

This is where it should be processed:

    public class LeerQR extends AppCompatActivity {
SurfaceView cameraView;
BarcodeDetector barcode;
CameraSource cameraSource;
SurfaceHolder holder;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_leer_qr);
    cameraView = (SurfaceView) findViewById(R.id.cameraView);
    cameraView.setZOrderMediaOverlay(true);
    holder = cameraView.getHolder();
    barcode = new BarcodeDetector.Builder(this)
            .setBarcodeFormats(Barcode.QR_CODE)
            .build();
    if(!barcode.isOperational()){
        Toast.makeText(getApplicationContext(), "Sorry, Couldn't setup the detector", Toast.LENGTH_LONG).show();
        this.finish();
    }
    cameraSource = new CameraSource.Builder(this, barcode)
            .setFacing(CameraSource.CAMERA_FACING_BACK)
            .setRequestedFps(24)
            .setAutoFocusEnabled(true)
            .setRequestedPreviewSize(1920,1024)
            .build();
    cameraView.getHolder().addCallback(new SurfaceHolder.Callback() {
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            try{
                if(ContextCompat.checkSelfPermission(LeerQR.this, android.Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED){
                    cameraSource.start(cameraView.getHolder());
                }
            }
            catch (IOException e){
                e.printStackTrace();
            }
        }



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

        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            cameraSource.stop();

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

        }

        @Override
        public void receiveDetections(Detector.Detections<Barcode> detections) {
            final SparseArray<Barcode> barcodes =  detections.getDetectedItems();
            if(barcodes.size() > 0){
                Intent intent = new Intent();
                //String [] variables = barcodes.split(=);
                intent.putExtra("barcode", barcodes.valueAt(0));
                setResult(RESULT_OK, intent);
                finish();
            }
        }
    });
}

}

What I want is to pass the result to the first fragment, to be able to process it there