Using CellSignalStrengthGsm only gives Integer.MAX_VALUE

Question

after seeing that question and the answers (thanks by the way) I wrote this code wich is pretty much the same as in the answers:

try {
        List<CellInfo> cellInfoList = telephonyManager.getAllCellInfo();
        for (CellInfo cellInfo : cellInfoList) {
            if (cellInfo instanceof CellInfoGsm) {
                CellInfoGsm cellInfoGsm = (CellInfoGsm) cellInfo;
                CellIdentityGsm cellIdentity = cellInfoGsm.getCellIdentity();
                final CellSignalStrengthGsm gsm = ((CellInfoGsm) cellInfo).getCellSignalStrength();
                rsrpValue = gsm.getDbm();
                pciValue = cellIdentity.getCid();
            } else if (cellInfo instanceof CellInfoCdma) {
                CellInfoCdma cellInfoCdma = (CellInfoCdma) cellInfo;
                CellIdentityCdma cellIdentity = cellInfoCdma.getCellIdentity();
                pciValue = cellIdentity.getBasestationId();
            } else if (cellInfo instanceof CellInfoLte){
                    CellInfoLte cellInfoLte = (CellInfoLte) cellInfo;
                    CellIdentityLte cellIdentity = cellInfoLte.getCellIdentity();
                    pciValue = cellIdentity.getPci();
            } else {
                throw new Exception("Unknown type of cell signal!");
            }
        }
    } catch (Exception e) {
        Log.e(TAG, "Unable to obtain cell signal information", e);
    }

But when I display rsrpValue or pciValue for GSM, I always get the maximum integer value (2147483647). I tried this on a phone with the API 17. Is there something wrong in my code?

Thanks

S4 mini i9195 GSM and LTE. Plus, It is really an instance of CellInfoGsm since rsrpValue is displaying 2147483647 (Integer.MAX_VALUE) and not 0 as I initialized it. — Grego, Nov 07 '13 at 16:03
shouldn't you be calling `cellIngGsm.getCellSignalStrength()` rather than `((CellInfoGsm) cellInfo).getCell...`? (not that it would change anything, though) — njzk2, Nov 07 '13 at 16:26
The code for getDbm is at https://android.googlesource.com/platform/frameworks/base.git/+/master/telephony/java/android/telephony/CellSignalStrengthGsm.java line 128. Apparently MAX_VALUES means unknown. — njzk2, Nov 07 '13 at 16:27
Yes it means unknown but I don't know why it is unknown. I tried with a LTE sim card and getPci() works. So I guess I am not using the good function for GSM. My goal is to get the info for LTE network. GSM was for testing while I was waiting for a LTE sim card. I will look for this error later. But for whoever is looking for LTE network information, this code works. — Grego, Nov 07 '13 at 16:48

score 1 · Accepted Answer · answered Nov 19 '13 at 17:11

Try to use the good old PhoneStateListener to listen for signal strength changes. Here is what worked for me. Use this to register the listener:

private TelephonyManager telManager = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
int currentSignalStrength = 0;
int asu = 0;

telManager.listen(new SignalStrengthListener(), PhoneStateListener.LISTEN_SIGNAL_STRENGTHS);

And this is the actual listener:

private class SignalStrengthListener extends PhoneStateListener{

    @Override
    public void onSignalStrengthsChanged(SignalStrength signalStrength)
        {
            super.onSignalStrengthsChanged(signalStrength);
            if (telManager.getPhoneType()== TelephonyManager.PHONE_TYPE_CDMA)
                currentSignalStrength = signalStrength.getCdmaDbm();                  
            else
                asu = signalStrength.getGsmSignalStrength();
        }
    }

Tested on Xperia Z which has the same problems using CellInfoGsm.

Thanks, this is what I did for LTE signal. I do not know why but CellSignalStrengthGsm (or CDMA or LTE) does not work on a galaxy S4 and S4 mini. It has been added since the API 17 but does not work on those devices even with android 4.2.2 maybe it will work on 4.3 — Grego, Nov 24 '13 at 17:47
On HTC One (Android 4.3) it's even worse. telephonyManager.getAllCellInfo(); is returning null...It's very manufacturer dependent. Best results on Nexus 5 so far. — Thilo, Nov 26 '13 at 12:33

Using CellSignalStrengthGsm only gives Integer.MAX_VALUE

1 Answers1