title: Android get Device Country Code
body: <p>I want to get device country code with out using sim card.</p>
  
  <p>e.g If Country : Sri lanka
         Country code : LK</p>
  
  <p>my final goal is get calling code (+94 for sri lanka)</p>
  
  <p>i tried with this </p>
  
  <pre><code>TelephonyManager tm = (TelephonyManager)this.getSystemService(getApplicationContext().TELEPHONY_SERVICE);
  String countryCodeValue = tm.getNetworkCountryIso();
  </code></pre>
  
  <p>but this return empty string </p>