TelephonyManager Tel; MyPhoneStateListener MyListener; /* Update the listener, and start it */ MyListener = new MyPhoneStateListener(); Tel = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE); Tel.listen(MyListener, PhoneStateListener.LISTEN_SIGNAL_STRENGTHS); private class MyPhoneStateListener extends PhoneStateListener { /* 從得到的信號強度,每個tiome供應商有更新 */ public void onSignalStrengthsChanged(SignalStrength signalStrength) {   super.onSignalStrengthsChanged(signalStrength);   Toast.makeText(getApplicationContext(),"Go to Firstdroid!!! GSM Cinr = "+ String.valueOf(signalStrength.getGsmSignalStrength()),Toast.LENGTH_SHORT).show();   } };