Java Application for Smartphones

Hello to all, I need an application for mobile smartphones written in Java that must work on Android phones. The application will be used to enter the water consuming for my clients. As input will have a file with the list of customers, address and the last read water meter index. For each customer, the reader goes with the phone and, trough application, enter the new water meter index. This information will be written in the same file starting with a certain position(let's say starting from character 20 will be write the new index). I need a very good Java programmer with experience in developing Java application for Android phones.