Sim - Hàm kiểm tra có sim hay không

public boolean isSimAvail(){
TelephonyManager telMgr = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);

if (telMgr.getSimState() != TelephonyManager.SIM_STATE_ABSENT){
//the phone has a sim card
return true;
} else {
//no sim card available
return false;
}
}