Can i retrieve the current telephone number?
<p>I'm writing an app for android (2.1+) and I'd like to use the telephone number of the current phone.
Lots of googling brought me the following:</p>

<pre><code>String number=(TelephonyManager)getApplicationContext().getSystemService(Context.TELEPHONY_SERVICE).getLine1Number();
</code></pre>

<p>That along with permission:  READ_PHONE_STATE.</p>

<p>My problem however is that it returns null.
While searching i noticed this question has been asked many times before and nearly in all of those questions it is said that the number simply isn't always available.</p>

<p>While testing I found that on my very own phone it gives me null.
BUT another app (e.q. WhatsApp) was able to recognize my phone number.</p>

<p>So then i wonder, how did they do it?</p>
