Development of cross-platform loyalty app

We are hiring a developer to create only the beginning of an application. If this milestone is completed well, there will be more work afterwards. The requirements are below. APP DESCRIPTION: This is a loyalty App that will be used by staff in a small shop. Loyalty cards with QR codes on, will be issued to customers. When a customer hands the card to the staff member, they will use a phone or tablet to scan the QR code. They can then assign points to the card ID. This points balances will be stored in a local DB and displayed whenever the card is scanned. TECHNICAL REQUIREMENTS: - The app only has to work on Android 4.x and above at this time - The app will need to be ported to iOS at some point - The app needs to work with multiple loyalty cards, example Loyalty cards will be supplied. - Unit Tests need to be supplied, along with the code. - The QR scanner needs to be able to switch between cameras, with a button on the scanning screen e.g. the user should be able to switch between the front and back cameras. - Having well-documented, legible code is just as important as having a working product. If you are not willing to put in the time to format, structure, and explain your code, please do NOT bid on this project. Code should be styled according to appropriate style conventions; Meaningful variable names ("appPhotoId" not "apid"); All non-trivial functions documented with description of purpose, accepted inputs & expected result / output. OTHER REQUIREMENTS: - You must be fluent in English, both written and spoken. HTML INTERFACE MOCKUP: [login to view URL] EXAMPLE USER JOURNEY: Adding points to a customer's card - Customer hands loyalty card to the staff member - Staff member opens the loyalty app - Staff member scans the QR code on the loyalty card with the loyalty app - The card home page opens, which gives the staff member the option to choose to either add points or redeem a reward - Staff member chooses add points - The add points screen opens, which shows a field to enter a points value - Staff member enters the desired points value and presses add points, the add points success screen is shown - Staff member then presses the Home button to return to the home screen ON COMPLETION: For completion of this project, please supply an android .apk file, which we can use to test the functionality as described. Please also supply all documented source code and unit tests in a .zip file. PLEASE INCLUDE ANSWERS TO THESE QUESTIONS WITH YOUR PROPOSAL: - Please explain how you would port this code to iOS, and how much code do you think could be re-used? - How many APPs have you developed? - Do you have a portfolio of your work? If so, please provide a link. - Have you developed cross platform APPs before? If so please give examples. - Which cross-platform frameworks have you used? - How many hours do you think it will take to do this work? - What date can you start the work and what date will you finish? VERY IMPORTANT: To separate you from the spammers, please ensure you include answers to the questions asked above, at the beginning of your proposal. We will delete all bids that do not have at least one answer, since most bidders never read the requirements. Thank you for being one who does.