Listening for GSM signal strength changes.

gistfile1.java

public void registerListenForSignalStrengths(Context context)
{
	TelephonyManager tm = (TelephonyManager)context.getSystemService(TELEPHONY_SERVICE);
	tm.listen(mPhoneStateListener, PhoneStateListener.LISTEN_SIGNAL_STRENGTHS);
}

public void unregisterListenForSignalStrengths(Context context)
{
	TelephonyManager tm = (TelephonyManager)context.getSystemService(TELEPHONY_SERVICE);
	tm.listen(mPhoneStateListener, PhoneStateListener.LISTEN_NONE);
}

private PhoneStateListener mPhoneStateListener = new PhoneStateListener(){
	@Override
	public void onSignalStrengthsChanged(SignalStrength signalStrength)
	{
		if(signalStrength.isGsm()){
			Log.d("SIGNAL STRENGTH", String.valueOf(signalStrength.getGsmSignalStrength()));
		}
	}
};