Hello Sir,
I have read your requirement and I can provide you best solution for this.
Let me introduce myself, I am Angel (skype: project4angel) working as freelancer with team of 7 members on Android and iOS. You can see some of my previous projects in my portfolio.
Sir, I am very familiar with barcode scan, I have used that in 1 of my project and I have ready to go code for that, just need to change for save in file. I can give you perfect solution for this.
I would like to request you to lets have some words before you go further on this project.
Regards,
Angel.