Accessing AutoFocus/Flash with Google Vision BarCode Reader

Question

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

Answer 1

Here is a working kotlin variant:

private var flashmode: Boolean = false
private var camera: Camera? = null

private fun flashOnButton() {
    camera = getCamera(cameraSource)

    if (camera != null) {
        try {
            val param = camera!!.parameters

            param.setFlashMode(if (!flashmode) Camera.Parameters.FLASH_MODE_TORCH else Camera.Parameters.FLASH_MODE_OFF)
            camera?.parameters = param
            flashmode = !flashmode
        } catch (e: java.lang.Exception) {
            e.printStackTrace()
        }
    }
}

private fun getCamera(cameraSource: CameraSource): Camera? {
    val declaredFields = CameraSource::class.java.declaredFields

    for (field in declaredFields) {
        if (field.type === Camera::class.java) {
            field.isAccessible = true

            try {
                val camera = field.get(cameraSource) as Camera
                return if (camera != null) {
                    camera
                } else null
            } catch (e: IllegalAccessException) {
                e.printStackTrace()
            }

            break
        }
    }

    return null
}

This solution works for now. But I don't know how to handle this, when android.hardware.Camera is not supported anymore in the future. Maybe there is a better solution without android.hardware.Camera?

Answer 2

Just use the CameraSource directly.

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

And you will have the ability to use flash/focus.

CameraSource
.setFlashMode()
.setFocusMode()

Answer 3

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.