A simple way to customize the screen of the BarcodeScanner

I assume you are referring to: https://github.com/phonegap/phonegap-plugin-barcodescanner

If so you just need to fork the project and customise the scanner overlays.

For example (iOS): https://github.com/phonegap/phonegap-plugin-barcodescanner/blob/master/src/ios/scannerOverlay.xib