Write an Android application

Hello, There is an open source Android app which needs to be tweaked to include a new module in it. The App is an Expense Tracker which helps you track your daily day to day expense in offline mode. The source code: [login to view URL] Play Store link - [login to view URL] I would like to have a new module in the app, where the app would forecast upcoming expenses for the next 30 days on the basis of calculating average from the previous 60 days of data for a given category and warn users. Ex: Grocery expenses for the last and previous month averaged out to be $25, hence the upcoming month a forecast can be made of $25 for groceries. This will help the user to be prepared for the essential monthly expenses. A graphical representation (pie chart) of the same will help the end user to forecast his upcoming expenses. Rest of the app is to be retained as it is.