Android 监听GSM信号

TelephonyManager telephoneyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
PhoneSignalStateListener phoneSignalStateListener = new PhoneSignalStateListener();
telephoneyManager.listen(phoneSignalStateListener, PhoneStateListener.LISTEN_SIGNAL_STRENGTH);
 
 class PhoneSignalStateListener extends PhoneStateListener
 {
  @Override
  public void onSignalStrengthChanged(int asu)
  {
   Log.d("GSM信号:", asu+"");
   super.onSignalStrengthChanged(asu);
  }
 } 
 
//使用完后一定要清除监听,否则会造成内存泄漏
telephoneyManager.listen(phoneSignalStateListener, PhoneStateListener.LISTEN_NONE);