Develop and Android application together with server backend

We are a company involved in the trading, marketing and supplying of food products with a focus on Traditional Chinese Medicines (TCM), herbs and spices, marine products, and others. We wish to develop a mobile application for the Android platform to for our sales team together with a cloud-based backend. The application should have the following functions: - Allow the sales team to carry out sales function (e.g. select products from list or enter product via auto-complete, enter price, quantity, remarks) - Allow the sales team to carry out customer relationship management (CRM) functions (e.g. check recent sale, check outstanding balance, etc.) - Allow the office team to carry out inventory management (e.g. automatic generation of Sales Order, Delivery Order, Invoice, Packing List, etc.) - Allow the management to monitor the sales team (e.g. Check recent sales location, check sales revenue to date, etc.) We want our application to: - Be bilingual (English and Mandarin Chinese); - Make use of open source software and technologies; - Make use of existing tools, software and platforms to reduce development time; Existing Android Application similar to our needs are: - Base CRM [login to view URL] - Focus ERP [login to view URL] - Sales Manager [login to view URL]