Xamarin Mobile Sales App

We are looking for an experienced Xamarin/Android developer who can develop a sales mobile app (Android 4+, min res 480x800 px, able to resize up to 1280x800) and the tools needed for file exchange with a desktop PC, using C# and Visual Studio Community Edition (2015 or 2017) It must be able to read and write to text files in order to import or export data from/to a Windows computer and to send report data to a SMS number or email address. IMPORTANT: For any bid to be considered, it must start with the phrase "Bid for Mobile Elciel". Project is divided into three tasks: TASK 1: The developer must make a C# DLL interfase between the mobile app and a USB connected desktop computer. This C# DLL must provide the following functions: 1- CopyToDevice: Copies a file from the desktop computer to a USB connected device. 2- CopyFromDevice: Copies a file from the USB connected device to a desktop computer 3- SetDeviceName : assigns a friendly device name to a connected Device, stored wherever you like. 4- GetDeviceName : read the previously assigned friendly device name from the connected device in order to ID it. TASK 2: Primitive app specs: 1- Import button: the app must check if exists a exchange file with data to process newer than the last exchange file used (originated in a desktop computer and copied with the before mentioned C# DLL). If so, the app must warn the user and ask for confirmation in order to replace the existing information for the new one. Upon confirmation, the app must recreate the SQLite database and import the new working data into it and store the processing date (to be compared next time). We will provide full database structure and the text file's specs (character delimited field's format). 2- Export Button: following the same specifications used to import data, this task creates a new text file with database's data and must be able to send it to an e-mail adress. 3- The app must send current GPS position to a specific email or SMS phone number at previously set time intervals TASK 3: The final sales app has a 17 screens GUI. We will provide the detailed descriptions and proposed sketchs for most of them. The app must be able to take and store pictures, customer's signatures and current GPS position and to read EAN 13 barcode. PAYMENT: --------------------- We will make an initial milestone deposit before the start of each task and release payments according to the following milestones: Milestone 1 (7.5 % of total project budget): after approval of working app with task 1 completed Milestone 2 (7.5 % of total project budget): after delivery of source code of app with task 1 completed Milestone 3 (12.5 % of total project budget): after approval of final working app with tasks 1 and 2 completed Milestone 4 (12.5 % of total project budget): after delivery of source code of app with tasks 1 and 2 completed Milestone 5 (30 % of total project budget): after approval of final working app with complete tasks 1, 2 and 3. Milestone 4 (30 % of total project budget): after delivery of source code with tasks 1, 2 and 3 completed. IMPORTANT ************* a) We'll appreciate if you can state how soon you can finish this project, since we're in a hurry. ** Development time and reassurements offered to ease our fears of undesired delays will be key factor in bid evaluation .** b) We need full commented source code and app copyrights. Good programming practices, very clear code and robust error handling are a must. Patterns and unit testing use are not mandatories but appreciated If our experience it's satisfactory after project's end, we are very likely to need more work to be done in another projects. Please feel free to send your alternate proposal, any questions or ask for a more detailed spec if you need it in order to bid. Local time is GMT -3. We want to award the project as soon as possible and need for the developer to start right away. Thank you for your interest.