Accessing AutoFocus/Flash with Google Vision BarCode Reader

I am playing with the original example of BarCode scanner here:https://github.com/googlesamples/android-vision/blob/master/visionSamples/barcode-reader/app/src/main/java/com/google/android/gms/sa...

I am playing with the original example of BarCode scanner here:

https://github.com/googlesamples/android-vision/blob/master/visionSamples/barcode-reader/app/src/main/java/com/google/android/gms/samples/vision/barcodereader/BarcodeCaptureActivity.java

They are able to start the AutoFocus/Flash within the camera factory like this:

    // Creates and starts the camera.  Note that this uses a higher resolution in comparison
    // to other detection examples to enable the barcode detector to detect small barcodes
    // at long distances.
    CameraSource.Builder builder = new CameraSource.Builder(getApplicationContext(), barcodeDetector)
            .setFacing(CameraSource.CAMERA_FACING_BACK)
            .setRequestedPreviewSize(1600, 1024)
            .setRequestedFps(15.0f);

    // make sure that auto focus is an available option
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
        builder = builder.setFocusMode(
                autoFocus ? Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE : null);
    }

    mCameraSource = builder
            .setFlashMode(useFlash ? Camera.Parameters.FLASH_MODE_TORCH : null)
            .build();

However this method on cameraSource builder is gone in current version and so this setting cannot be accessed. Also I need to change the FlashMode during usage, so that is not the way to do it either. I found this ugly solution to accessing the camera:

public static Camera getCamera(@NonNull CameraSource cameraSource) {
    Field[] declaredFields = CameraSource.class.getDeclaredFields();

    for (Field field : declaredFields) {
        if (field.getType() == Camera.class) {
            field.setAccessible(true);
            try {
                Camera camera = (Camera) field.get(cameraSource);
                if (camera != null) {
                    return camera;
                }

                return null;
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }

            break;
        }
    }

    return null;
}

Although it works, it does not help: when calling getParameters().setFocusMode() I am getting this exception:

Attempt to invoke virtual method 'android.hardware.Camera$Parameters android.hardware.Camera.getParameters()' on a null object reference

Obviously what I am doing is not a right way to do it, but there seem to be no documentation about it.

Thanks for hints.

Just optimize your code as following and you have to call this method after building Camera Source class.

private Camera camera = null;
boolean flashmode=false;
private void flashOnButton() {
    camera=getCamera(mCameraSource);
    if (camera != null) {
        try {
            Camera.Parameters param = camera.getParameters();
         param.setFlashMode(!flashmode?Camera.Parameters.FLASH_MODE_TORCH :Camera.Parameters.FLASH_MODE_OFF);
            camera.setParameters(param);
            flashmode = !flashmode;
            if(flashmode){
                showToast("Flash Switched ON");
            }
            else {
                showToast("Flash Switched Off");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}
private static Camera getCamera(@NonNull CameraSource cameraSource) {
    Field[] declaredFields = CameraSource.class.getDeclaredFields();

    for (Field field : declaredFields) {
        if (field.getType() == Camera.class) {
            field.setAccessible(true);
            try {
                Camera camera = (Camera) field.get(cameraSource);
                if (camera != null) {
                    return camera;
                }
                return null;
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
            break;
        }
    }
    return null;
}

This will help you to enable flash in Google Vision Api using camerasource object.

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