我在我的应用程序中使用react-navigation的DrawerNavigator。我想检测用户何时拖动打开侧边菜单，以便我可以执行某些操作，例如关闭打开的键盘。我怎样才能做到这一点？我似乎无法在文档中找到解决方案。谢谢。
import React from 'react';
import { Dimensions } from 'react-native';
import { Icon } from 'react-native-elements';
import { DrawerNavigator, StackNavigator, addNavigationHelpers } from 'react-navigation';
//redux related imports
import { createStore, combineReducers } from 'redux';
import { Provider, connect } from 'react-redux';
import Attendance from './containers/pages/Attendance';
import Fees from './containers/pages/Fees';
import Exams from './containers/pages/Exams';
import InitializeUser from './containers/pages/InitializeUser';
import Landing from './Landing';
import Login from './containers/pages/Login';
import Search from './containers/pages/Search';
import Staff from './containers/pages/Staff';
import Stats from './containers/pages/Stats';
import …