Initialize TextRecognizer and CameraSource

MainActivity.java

private void startCameraSource() {

        //Create the TextRecognizer
        final TextRecognizer textRecognizer = new TextRecognizer.Builder(getApplicationContext()).build();

        if (!textRecognizer.isOperational()) {
            Log.w(TAG, "Detector dependencies not loaded yet");
        } else {

            //Initialize camerasource to use high resolution and set Autofocus on.
            mCameraSource = new CameraSource.Builder(getApplicationContext(), textRecognizer)
                    .setFacing(CameraSource.CAMERA_FACING_BACK)
                    .setRequestedPreviewSize(1280, 1024)
                    .setAutoFocusEnabled(true)
                    .setRequestedFps(2.0f)
                    .build();

            /**
             * Add call back to SurfaceView and check if camera permission is granted.
             * If permission is granted we can start our cameraSource and pass it to surfaceView
            */
            mCameraView.getHolder().addCallback(new SurfaceHolder.Callback() {
                @Override
                public void surfaceCreated(SurfaceHolder holder) {
                    try {

                        if (ActivityCompat.checkSelfPermission(getApplicationContext(),
                                Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {

                            ActivityCompat.requestPermissions(MainActivity.this,
                                    new String[]{Manifest.permission.CAMERA},
                                    requestPermissionID);
                            return;
                        }
                        mCameraSource.start(mCameraView.getHolder());
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }

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

                /**
                * Release resources for cameraSource
                */    
                @Override
                public void surfaceDestroyed(SurfaceHolder holder) {
                    mCameraSource.stop();
                }
            });

            //Set the TextRecognizer's Processor.
            textRecognizer.setProcessor(new Detector.Processor<TextBlock>() {
                @Override
                public void release() {
                }

                /**
                 * Detect all the text from camera using TextBlock and the values into a stringBuilder
                 * which will then be set to the textView.
                 * */
                @Override
                public void receiveDetections(Detector.Detections<TextBlock> detections) {
                    final SparseArray<TextBlock> items = detections.getDetectedItems();
                    if (items.size() != 0 ){

                        mTextView.post(new Runnable() {
                            @Override
                            public void run() {
                                StringBuilder stringBuilder = new StringBuilder();
                                for(int i=0;i<items.size();i++){
                                    TextBlock item = items.valueAt(i);
                                    stringBuilder.append(item.getValue());
                                    stringBuilder.append("\n");
                                }
                                mTextView.setText(stringBuilder.toString());
                            }
                        });
                    }
                }
            });
        }
    }