Android获取基站信号强度问题？请看代码

 public class MainActivity extends AppCompatActivity {
        private static final String TAG = "GSMCellLocationActivity";
        TelephonyManager telephonyManager;
        MyPhoneStateListener MyListener;
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            final TextView textView1 = (TextView) findViewById(R.id.text1);
            final TextView textView2 = (TextView) findViewById(R.id.text2);
            Button button= (Button) findViewById(R.id.button1);
             telephonyManager= (TelephonyManager) MainActivity.this.getSystemService(Context.TELEPHONY_SERVICE);
            MyListener = new MyPhoneStateListener();
            button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
    
                    String operator = telephonyManager.getNetworkOperator();
                    /**通过operator获取 MCC 和MNC */
                    int mcc = Integer.parseInt(operator.substring(0, 3));
                    int mnc = Integer.parseInt(operator.substring(3));
                    GsmCellLocation location = (GsmCellLocation) telephonyManager.getCellLocation();
                    /**通过GsmCellLocation获取中国移动和联通 LAC 和cellID */
                    int lac = location.getLac();
                    int cellid = location.getCid();
                    System.out.println("**"+mcc+"A"+mnc+"A"+lac+"A"+cellid);
                    textView1.setText("国家编号："+mcc+"运营商编号："+mnc+"LAC："+lac+"CellID："+cellid);
                    List<CellInfo> infos = telephonyManager.getAllCellInfo();
            **// List<NeighboringCellInfo> infos = telephonyManager.getNeighboringCellInfo();
          //这个方法在使用时，size一直为0，是为什么？**
                    StringBuffer sb = new StringBuffer("总数 : " + infos.size() + "\n");
                    for (CellInfo info1 : infos) { // 根据邻区总数进行循环
                        //  sb.append(" LAC : " + info1.getLac()); // 取出当前邻区的LAC
                        //  sb.append(" CID : " + info1.getCid()); // 取出当前邻区的CID
                        sb.append(" CID : " + info1.toString()); // 取出当前邻区的CID
                        //  sb.append(" BSSS : " + (-113 + 2 * info1.getRssi()) + "\n"); // 获取邻区基站信号强度
                    }
    
                    Log.i(TAG, " 获取邻区基站信息:" + sb.toString());
                    textView2.setText(sb.toString());
                }
            });
            telephonyManager.listen(MyListener, PhoneStateListener.LISTEN_SIGNAL_STRENGTHS);
           // telephonyManager.listen(celllistener, PhoneStateListener.LISTEN_CELL_LOCATION); // 基站位置的变化
        }
    
    
    
        private class MyPhoneStateListener extends PhoneStateListener
        {
            /* Get the Signal strength from the provider, each tiome there is an update  从得到的信号强度,每个tiome供应商有更新*/
            @Override
    
      
    
      public void onSignalStrengthsChanged(SignalStrength signalStrength)
        {
            super.onSignalStrengthsChanged(signalStrength);
            **if (signalStrength.getGsmSignalStrength() != 99) {
                Toast.makeText(getApplicationContext(),
                        "Go to Firstdroid!!! GSM Cinr = " + String.valueOf(signalStrength.getGsmSignalStrength() * 2 - 113) + "dbM", Toast.LENGTH_SHORT).show();
                        //这里toast的数据是基站信号强度吗？
                      //手机信号强度和基站信号强度一样吗？
                System.out.println("****" + String.valueOf(signalStrength.getGsmSignalStrength() * 2 - 113));**
            }
        }
        }
    }