Гусев Максим Игоревич

        public class MainActivity extends AppCompatActivity {

        public static TextView textView;
        private TextureView cameraTextureView;
        private Button readButton;
        private HandlerThread backgroundThread;
        private ImageView imageView;
        private Spinner spinner;
        public static String qrResult = "0";
        Bitmap barcode_bitmap;

        @RequiresApi(api = Build.VERSION_CODES.M)
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED ||
                    (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED))
            {
                requestPermissions(new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
            }

            textView = findViewById(R.id.textView);
            readButton = findViewById(R.id.readButton);
            imageView = findViewById(R.id.imageView);
            spinner = findViewById(R.id.spinner);

            readButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    startActivityForResult(new Intent(getApplicationContext(), ScanCodeActivity.class), 1);
                }
            });
        }

        @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            if (resultCode == RESULT_OK) {
                new Client().execute();
            }
        }

        private static Bitmap encodeAsBitmap(String contents, BarcodeFormat format, int img_width, int img_height)
                throws WriterException {
            String contentsToEncode = contents;
            if (contentsToEncode == null) {
                return null;
            }
            Map hints = null;
            String encoding = guessAppropriateEncoding(contentsToEncode);
            if (encoding != null) {
                hints = new EnumMap(EncodeHintType.class);
                hints.put(EncodeHintType.CHARACTER_SET, encoding);
            }
            MultiFormatWriter writer = new MultiFormatWriter();
            BitMatrix result;
            try {
                result = writer.encode(contentsToEncode, format, img_width, img_height, hints);
            } catch (IllegalArgumentException iae) {
                // Unsupported format
                return null;
            }
            int width = result.getWidth();
            int height = result.getHeight();
            int[] pixels = new int[width * height];
            for (int y = 0; y < height; y++) {
                int offset = y * width;
                for (int x = 0; x < width; x++) {
                    pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;
                }
            }

            Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
            bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
            return bitmap;
        }

        private static String guessAppropriateEncoding(CharSequence contents) {

            for (int i = 0; i < contents.length(); i++) {
                if (contents.charAt(i) > 0xFF) {
                    return "UTF-8";
                }
            }
            return null;
        }

        public void getQRButtonClick(View view) throws WriterException {
            new Client().execute();
        }
        class Client extends AsyncTask
        {
            String server = "https://secure-refuge-57247.herokuapp.com/ticket";
            String code;
            String answer;
            @SuppressLint("WrongThread")
            @Override
            protected String doInBackground(String... strings) {
                BufferedReader reader = null;
                try {
                    @SuppressLint("WrongThread") URL url = new URL(server+"?a="+spinner.getSelectedItemPosition()+"&b="+qrResult);
                    HttpURLConnection connection = (HttpURLConnection)url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setReadTimeout(10000);
                    connection.connect();
                    reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                    answer = reader.readLine();
                    if(qrResult == "0") {

                        //imageView.setImageBitmap(barcode_bitmap);


                        if(answer.compareTo("No more tickets") == 0){
                            textView.setTextColor(Color.rgb(128, 0, 128));
                            textView.setText(answer);
                        }
                        else{
                            barcode_bitmap = encodeAsBitmap(answer, BarcodeFormat.QR_CODE, 300, 300);
                        }
                    }
                    else {
                        if(answer.compareTo("correct") == 0){
                            textView.setTextColor(Color.GREEN);
                        }
                        else {
                            textView.setTextColor(Color.RED);
                        }
                        textView.setText(answer);
                    }
                } catch (IOException | WriterException e) {
                    e.printStackTrace();
                }
                finally {
                    if (reader != null) {
                        try {
                            reader.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
                return null;
            }

            @Override
            protected void onPreExecute()
            {
                super.onPreExecute();
            }

            @Override
            protected void onPostExecute(String result)
            {
            super.onPostExecute(result);
                imageView.setImageBitmap(barcode_bitmap);
            }

        }
    }