Decoding Qr using vuforia+unity+zxing

Hey Guys, I am currently trying to use vuforia+zxing+unity to decode Qr codes.I have tried most of the codes and guidelines given online,but none worked,I tried using Texture2D by taking screenshots,but it makes my app insanely slow(but it works).I was hoping that someone could give some help or guidance to help me through this. Any help is greatly appreciated