TelephonyManager.getLine1Number() failing?

I want to get phone number of android device. I use this code:

TelephonyManager tm = (TelephonyManager)this.getApplicationContext().getSystemService(Context.TELEPHONY_SERVICE); 
String phoneNumber=  tm.getLine1Number();

On my phone (HTC Wildfire) I can not get phone number - all I get is empty string. If I run code on emulatur, phone number is normally showed.

If I go to Settings=>About phone=>Phone identity->Phone number, phone number is "Unknown".

Where is the problem? Is something wrong with my SIM?

We had the same problem in our project. The conclusion was that it depends on the SIM card.

What happened to us:

• Galaxy S with AT&T SIM card: can read phone number, Settings shows number
• Same Galaxy with an European SIM card: cannot read the number and "unknown" in Settings (cell phone was perfectly functional, just couldn't read the number)

This has been reported in other forums as well.

In the end we decided to ask the user for the phone number. A bit more involved, actually: if( "SIM card present" && "cannot read the cell number") "ask user"; . Otherwise we will keep bugging the user that doesn't a SIM card in the first place.