QRCodeReaderView implements an Android view which show camera and notify when there’s a QR code inside the preview.

It uses the zxing open-source, multi-format 1D/2D barcode image processing library.

Adding the library to your project

Add QRCodeReaderView dependency to your build.gradle

dependencies{
    compile 'com.dlazaro66.qrcodereaderview:qrcodereaderview:2.0.0'
}

First use

• Add to your layout a QRCodeReaderView

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

• Create an Activity which implements onQRCodeReadListener, and use it as a listener of the QrCodeReaderView.
• Make sure you have camera permissions in order to use the library. (https://developer.android.com/training/permissions/requesting.html)

Then in your Activity, you can use it as follows:

public class DecoderActivity extends Activity implements OnQRCodeReadListener {

private TextView resultTextView;
private QRCodeReaderView qrCodeReaderView;

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

    qrCodeReaderView = (QRCodeReaderView) findViewById(R.id.qrdecoderview);
    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 front camera preview
    qrCodeReaderView.setFrontCamera();

    // 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) {
    resultTextView.setText(text);
}

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

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