public class QRCode extends AppCompatActivity {

    EditText txtInput;
    Button btnCreateBarcode;
    ImageView imgBarcode;
    String text2Qr;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_qrcode);
        txtInput = (EditText) findViewById(R.id.txtInput);
        btnCreateBarcode = (Button) findViewById(R.id.btnCreateBarcode);
        imgBarcode = (ImageView) findViewById(R.id.imgBarcode);
        btnCreateBarcode.setOnClickListener(new View.OnClickListener() {
        @Override

        public void onClick(View view) {
                text2Qr = txtInput.getText().toString().trim();
                MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
                try {
                    BitMatrix bitMatrix = multiFormatWriter.encode(text2Qr, BarcodeFormat.QR_CODE, 200, 200);
                    BarcodeEncoder barcodeEncoder = new BarcodeEncoder();
                    Bitmap bitmap = barcodeEncoder.createBitmap(bitMatrix);
                    imgBarcode.setImageBitmap(bitmap);
                }
                catch (WriterException e) {
                    e.printStackTrace();
                }

            }
        });
        }
        }