Get SIM card status in Android phone

Public String Readsimcard () {
Telephonymanager TM = (Telephonymanager) this.getsystemservice (telephony_service)//access to related system services
StringBuffer sb = new StringBuffer ();
Switch (tm.getsimstate ()) {//getsimstate () Gets the status of the SIM with the following 6 status
Case TelephonyManager.SIM_STATE_ABSENT:sb.append ("no card");
Case TelephonyManager.SIM_STATE_UNKNOWN:sb.append ("Unknown state");
Case TelephonyManager.SIM_STATE_NETWORK_LOCKED:sb.append ("Need networkpin unlock");
Case TelephonyManager.SIM_STATE_PIN_REQUIRED:sb.append ("Need PIN unlocking");
Case TelephonyManager.SIM_STATE_PUK_REQUIRED:sb.append ("Need PUK unlock");
Case TelephonyManager.SIM_STATE_READY:sb.append ("good");
}

if (Tm.getsimserialnumber ()!=null) {
Sb.append ("@" + tm.getsimserialnumber (). toString ());
}else{
Sb.append ("@ cannot obtain SIM card number");
}

if (Tm.getsimoperator (). Equals ("")) {
Sb.append ("Cannot obtain supplier code");
}else{
Sb.append ("@" + tm.getsimoperator (). toString ());
}

if (Tm.getsimoperatorname (). Equals ("")) {
Sb.append ("Unable to obtain supplier");
}else{
Sb.append ("@" + tm.getsimoperatorname (). toString ());
}

if (Tm.getsimcountryiso (). Equals ("")) {
Sb.append ("@ Unable to acquire nationality");
}else{
Sb.append ("@" + tm.getsimcountryiso (). toString ());
}

if (Tm.getnetworkoperator (). Equals ("")) {
Sb.append ("@ Unable to obtain network operator");
} else {
Sb.append ("@" + tm.getnetworkoperator ());
}
if (Tm.getnetworkoperatorname (). Equals ("")) {
Sb.append ("@ Unable to obtain network operator name");
} else {
Sb.append ("@" + tm.getnetworkoperatorname ());
}
if (tm.getnetworktype () = = 0) {
Sb.append ("@ Cannot get network type");
} else {
Sb.append ("@" + tm.getnetworktype ());
}
return sb.tostring ();
}