Programmatically obtain the phone number of the Android phone

How can I programmatically get the phone number of the device that is running my android app?

Answer

Code:

TelephonyManager tMgr = (TelephonyManager)mAppContext.getSystemService(Context.TELEPHONY_SERVICE);
String mPhoneNumber = tMgr.getLine1Number();

Required Permission:

Caveats:

According to the highly upvoted comments, there are a few caveats to be aware of. This can return null or "" or even "???????", and it can return a stale phone number that is no longer valid. If you want something that uniquely identifies the device, you should use getDeviceId() instead.