wifi_scan.java

if (!mWifiScanning && timeNow > mWifiLastTime + WIFI_SLEEP_TIMEOUT)
{
  if (mWifiBroadcastReceiver != null && !mWifiRegistered)
  {
    mContext.registerReceiver(mWifiBroadcastReceiver, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
    mWifiRegistered = true;
  }
  
  if (mWifiManager.startScan()) 
  {
    mWifiTime = timeNow;

    try 
    { 
      mContext.unregisterReceiver(mWifiBroadcastReceiver);
      mWifiRegistered = false;
    } catch (Throwable e) { }
  }
}