title: getLine1Number() Returns blank, not null
body: <p>I want to get Mobile Number of Device. I have used following code reference by <a href="https://stackoverflow.com/users/176761/alex-volovoy">Alex Volovoy's</a> <strong><a href="https://stackoverflow.com/a/2480307/1318946">This Link</a></strong></p>
  
  <pre><code>TelephonyManager tMgr = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
  String mPhoneNumber = tMgr.getLine1Number();
  
  Log.d("msg", "Phone : "+mPhoneNumber);
  </code></pre>
  
  <p><strong>OUTPUT in Logcat:</strong></p>
  
  <h3>Without Simcard Phones Returns:</h3>
  
  <pre><code>02-01 17:22:45.472: D/msg(29102): Phone : null
  </code></pre>
  
  <h3>With Simcard:</h3>
  
  <pre><code>02-01 17:22:45.472: D/msg(29102): Phone : 
  </code></pre>
  
  <p>I have also taken permission in <strong><code>&lt;uses-permission android:name="android.permission.READ_PHONE_STATE"/&gt;</code></strong> in <strong><code>AndroidManifest.xml</code></strong></p>
  
  <p>So what should i do? Is there any Mistake?</p>