get SignalStrength without Using PhoneStateListene

问题:

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 signal strength changes and I need to get the value of signalstrength according to a different criteria.

Thanks in advance.

回答1:

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.

回答2:

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

回答3:

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