Activate the device's camera, and wait for the user to scan a QR code.
- qrType: Type of the code that is the be scanned (QR, Barcode, ...)
- qrEnableFlip: if true, allow the user to switch between front- and back camera
- qrFrontCamera: if true, prefer to use the device's front camera, if one exists
- resGroup: group to store the read QR-code in
- resKey: key to store the read QR-code in
- Stores the content of the QR code that was read in the given variable
- On success: A proper QR code has been scanned
- On cancelled: The scan has been aborted