Android QR Reading

QrActivity.java

public class QrActivity extends AppCompatActivity implements QRCodeReaderView.OnQRCodeReadListener {
    private QRCodeReaderView qrCodeReaderView;
    private static final int MY_CAMERA_REQUEST_CODE = 100;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_qr);

        if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA}, MY_CAMERA_REQUEST_CODE);
        }

        qrCodeReaderView = findViewById(R.id.view_qrdecoder);
        qrCodeReaderView.setOnQRCodeReadListener(this);

        // Use this function to enable/disable decoding
        qrCodeReaderView.setQRDecodingEnabled(true);

        // Use this function to change the autofocus interval (default is 5 secs)
        qrCodeReaderView.setAutofocusInterval(2000L);

        // Use this function to enable/disable Torch
        qrCodeReaderView.setTorchEnabled(true);

        // Use this function to set back camera preview
        qrCodeReaderView.setBackCamera();
    }

    // Called when a QR is decoded
    // "text" : the text encoded in QR
    // "points" : points where QR control points are placed in View
    @Override
    public void onQRCodeRead(String text, PointF[] points) {
        System.out.println("*** -> " + text);
    }

    @Override
    protected void onResume() {
        super.onResume();
        qrCodeReaderView.startCamera();
    }

    @Override
    protected void onPause() {
        super.onPause();
        qrCodeReaderView.stopCamera();
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == MY_CAMERA_REQUEST_CODE) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                Toast.makeText(this, "camera permission granted", Toast.LENGTH_LONG).show();
            } else {
                Toast.makeText(this, "camera permission denied", Toast.LENGTH_LONG).show();
            }
        }
    }
}

// https://github.com/dlazaro66/QRCodeReaderView

/*
<com.dlazaro66.qrcodereaderview.QRCodeReaderView
        android:id="@+id/view_qrdecoder"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
*/