Android获取已连接的蓝牙设备

Android手机连接蓝牙设备后，不能通过搜索再次搜到，网上各种方法试了均无效，反射机制也用了没啥用，哪位大神可以帮忙

 public void checkConnected()
{
  // true == headset connected && connected headset is support hands free
  int state = BluetoothAdapter.getDefaultAdapter().getProfileConnectionState(BluetoothProfile.HEADSET);
  if (state != BluetoothProfile.STATE_CONNECTED)
    return;

  try
  {
    BluetoothAdapter.getDefaultAdapter().getProfileProxy(_context, serviceListener, BluetoothProfile.HEADSET);
  }
  catch (Exception e)
  {
    e.printStackTrace();
  }
}

private ServiceListener serviceListener = new ServiceListener()
{
  @Override
  public void onServiceDisconnected(int profile)
  {

  }

  @Override
  public void onServiceConnected(int profile, BluetoothProfile proxy)
  {
    for (BluetoothDevice device : proxy.getConnectedDevices())
    {
      Log.i("onServiceConnected", "|" + device.getName() + " | " + device.getAddress() + " | " + proxy.getConnectionState(device) + "(connected = "
          + BluetoothProfile.STATE_CONNECTED + ")");
    }

    BluetoothAdapter.getDefaultAdapter().closeProfileProxy(profile, proxy);
  }
};