title: Get data from devices through bluetooth
body: <p>I need to build a car android app that displays various data from users phones when they are paired with the app.  by various data I mean their contact list , battery status etc..</p>
  
  <p>which API's do I need to implement to do that ? I have seen the Bluetooth API's but as I don't have any control over the phones that pair with my app , I need somehow to get that data automatically . </p>