Android XzingScanner : How to customise ZxingScanner layout ? (add button)

I'm realising a barcode scanner using Zxing Scanner, everything is working for this part but now I would like to add one button on the layout (to toggle on/off flashlight). I checked everywhere on the internet but found nothing.

So, here is my questions :

• Is it possible de ton find ou modify the .xml to add a button ? If yes, how to find this file ?

• Is there a feature already implemented somewhere to add some elements in the layout?

This is how I'm calling ZXingScannerView :

scannerView = new ZXingScannerView(this);
setContentView(scannerView);

This is good to customize QR/Barcode scanner with ZXing library

https://github.com/journeyapps/zxing-android-embedded

You can see sample app project there and customize (add button, set flash on/off) in yourself.

Also there is another library, but it's not using ZXing.

https://github.com/googlesamples/android-vision

It's deprecated, is now a part of ML Kit, but still is available to use.

[Update]

Please import this library into your project. (You can see how can import it from below link.)

https://github.com/journeyapps/zxing-android-embedded#adding-aar-dependency-with-gradle

After imported, you can update the layout.xml of your barcode scanner's activity.

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/topLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:keepScreenOn="true">

    <com.journeyapps.barcodescanner.DecoratedBarcodeView
        android:id="@+id/barcode_scanner"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="center" />
    
    <Button
        android:id="@+id/btn_flash"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|center"
        android:text="Flash"/>
    
</FrameLayout>

com.journeyapps.barcodescanner.DecoratedBarcodeView is BarcodeScanner view. And Button is just to turn on/off flash.

This is BarcodeScanner's Activity.

public class ScanQRActivity extends BaseActivity {

    private static final String TAG = "ScanQRActivity";

    private DecoratedBarcodeView barcodeView;

    private boolean isFlashOn;

    /**
     * Initializes the UI and creates the detector pipeline.
     */
    @Override
    public void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        setContentView(R.layout.activity_scan_qr);

        isFlashOn = false;

        barcodeView = findViewById(R.id.barcode_scanner);
        Collection<BarcodeFormat> formats = Arrays.asList(BarcodeFormat.CODE_39); // Set barcode type
        barcodeView.getBarcodeView().setDecoderFactory(new DefaultDecoderFactory(formats));
        barcodeView.initializeFromIntent(getIntent());
        barcodeView.decodeContinuous(callback);

        Button btnFlash = findViewById(R.id.btn_flash);
        if (!hasFlash()) {
            btnFlash.setVisibility(View.GONE);
        }
        btnFlash.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                switchFlashlight();
            }
        });
    }

    private BarcodeCallback callback = new BarcodeCallback() {
        @Override
        public void barcodeResult(BarcodeResult result) {
            Log.e(TAG, result.getText()); // QR/Barcode result
        }

        @Override
        public void possibleResultPoints(List<ResultPoint> resultPoints) {
        }
    };

    /**
     * Check if the device's camera has a Flashlight.
     *
     * @return true if there is Flashlight, otherwise false.
     */
    private boolean hasFlash() {
        return getApplicationContext().getPackageManager()
                .hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);
    }

    public void switchFlashlight() {
        if (isFlashOn) {
            isFlashOn = false;
            barcodeView.setTorchOff();
        } else {
            isFlashOn = true;
            barcodeView.setTorchOn();
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        barcodeView.resume();
    }

    @Override
    protected void onPause() {
        super.onPause();
        barcodeView.pause();
    }
}

When QR/Barcode is scanned, you can get result from BarcodeCallback.barcodeResult function.