android app - JAVA - map with overlay controls

I need an app with map and some basic controls - to talk to a web service in JSON. We can take your feedback on how the API should work. The app needs to have a map on the main screen, with GPS location as an icon on the map, and other icons to show other items on the map that move around. There should be a button to tell the server their location. Another screen will need to record tracks of a trip - and display a line on the map showing where they have been. All of this needs to send updates every few seconds to our web service via JSON. This version won't require any authentication/registration, we'll just use a deviceID or something similar. There are a couple other small features, but you get the idea of size from this.