Android App :: Calendar and Address Book

We have a collaboration server sharing the calendar and address book information through a Web service. The calendar information is composed of 'events' (like appointments, meetings, reminders) and the address book information is composed of contact's information (like name, email, address, phone number). The android app must: 1) ask the user for authentication credentials (only the first time and store the credentials localy) 2) then authenticate against the server with those credentials 3) retrieve and display the Web service information From time to time (configurable) the android app must contact the collaboration server to sync the data. The app should have 3 tabs: 1) Calendar 2) Contacts (Address Book) 3) Setup (here the user can change the authentication credentials and configure the sync frequency) In addition, the user must have the hability of create calendar events and these events (created on the mobile devices) must be sent to the collaboration server. The same thing for the Contacts: The user must have the hability of create new contacts.