function starts an Android device's camera and allows the operator to scan a barcode. The barcode can be in several formats
, including QR codes. An optional string expression, message
, is displayed on top of the camera view and can be used to display instructions to the operator.
This function only works on Android devices and returns a blank string if used on another device.
The function returns a string value containing the barcode's value. If the operator canceled before a barcode could be successfully read, the function returns a blank string.