get SignalStrength without Using PhoneStateListener onSignalStrengthchanged

Question

does anyone know how to get the signal strength without having to call the onSignalStrengthChanged. The problem with onSignalStrengthchanged is that is it called when the s

Answer 1

There is another API in Android called CellInfo. But I am not sure whether signal strength returned by OnSignalStrengthsChanged() and CellInfo is same or not.

https://developer.android.com/reference/android/telephony/CellSignalStrength.html

Answer 2

On API level 17 only, here's some code that can be used in an Activity (or any other Context child class):

import android.telephony.CellInfo;
import android.telephony.CellInfoCdma;
import android.telephony.CellInfoGsm;
import android.telephony.CellInfoLte;
import android.telephony.CellSignalStrengthCdma;
import android.telephony.CellSignalStrengthGsm;
import android.telephony.CellSignalStrengthLte;
import android.telephony.TelephonyManager;

try {
    final TelephonyManager tm = (TelephonyManager) this.getSystemService(Context.TELEPHONY_SERVICE);
    for (final CellInfo info : tm.getAllCellInfo()) {
        if (info instanceof CellInfoGsm) {
            final CellSignalStrengthGsm gsm = ((CellInfoGsm) info).getCellSignalStrength();
            // do what you need
        } else if (info instanceof CellInfoCdma) {
            final CellSignalStrengthCdma cdma = ((CellInfoCdma) info).getCellSignalStrength();
            // do what you need
        } else if (info instanceof CellInfoLte) {
            final CellSignalStrengthLte lte = ((CellInfoLte) info).getCellSignalStrength();
            // do what you need
        } else {
            throw new Exception("Unknown type of cell signal!");
        }
    }
} catch (Exception e) {
    Log.e(TAG, "Unable to obtain cell signal information", e);
}

Previous versions of Android require you to call the listener, there is no other alternative (see this link).

Also ensure that your application contains the appropriate permissions.

Answer 3

you can access SignalStrength via reflection call. Please go through the link for implementation http://blog.ajhodges.com/2013/03/reading-lte-signal-strength-rssi-in.html

Answer 4

Based on Andre's answer above, in Kotlin you can use this one-liner (again API 17+):

fun getRadioSignalLevel(): Int {
  return when (val info = telephonyManager.allCellInfo?.firstOrNull()) {
    is CellInfoLte   -> info.cellSignalStrength.level
    is CellInfoGsm   -> info.cellSignalStrength.level
    is CellInfoCdma  -> info.cellSignalStrength.level
    is CellInfoWcdma -> info.cellSignalStrength.level
    else             -> 0
  }
}