Android barcode scanning application

Hello, For our customer, a leading company in providing access and ticketing systems, we will need to recruit and hire for 1-year time a professional developer which will be in charge of design and develop a full access control application for mobile phones and tables. The selected person will sign a contract of $1,000/mo with a 1-year time. In order to hire the best developer which will suit our client need, we want you to develop and present a simple Android application with the following features: - scan barcode using mobile camera - check if barcode is valid - invalidate the barcode in the database I believe that this kind of simple application will give us the possibility to select the best developer for the full access control application that our customer wants to develop. I'm opened for details via private messages system.