title: TYPE_MAGNETIC_FIELD Android No data
body: <p>I have written some simple code for the Galaxy Tab 7 to show the TYPE_MAGNETIC_FIELD data. 
  Unfortunately this does not provide any data.</p>
  
  <p>I can see a TYPE_MAGNETIC_FIELD sensor (have checked it exists). I can successfully add a an event listener to it, however I never get any data from it. Other sensors work fine such as light and accelerometer. This is on a Galaxy Tab 7.  </p>
  
  <p><code>onSensorChanged(SensorEvent event)</code> is never fired for  a  <code>case Sensor.TYPE_MAGNETIC_FIELD:</code></p>
  
  <p>As such I get no data from the Magnetic Field Sensor.</p>
  
  <p>Anyone else getting this problem or know of a solution to it ?</p>
  
  <p>Many Thanks.</p>