使用React-navigation进行React-native:标题未显示在屏幕中

我有一个简单的React原生应用程序,使用React导航进行导航。我的问题是其中一个屏幕的标题和标题没有显示,即使它设置为 navigationOptions :

import React from "react";
import { View, Text } from "react-native";
import {
  createDrawerNavigator,
  createAppContainer,
  createStackNavigator
} from "react-navigation";

import ArticleList from "./screens/ArticleList";
import ArticleList2 from "./screens/ArticeList2";

import ArticleWebView from "./screens/ArticleWebView";

// create the Navigator to be used
const Stack = createStackNavigator({
  ArticleList: { screen: ArticleList },
  ArticleWebView: { screen: ArticleWebView }
});

const Drawer = createDrawerNavigator(
  {
    Stack: { screen: Stack },
    ArticleList2: { screen: ArticleList2 }
  },
  {
    initialRouteName: "Stack"
  }
);

// The container for the navigator
const AppContainer = createAppContainer(Drawer);

class App extends React.Component {
  render() {
    return <AppContainer />;
  }
}

export default App;

ArticleList2是一个非常简单的组件:

import React from "react";
import { View, Text } from "react-native";

import ArticleListComponent from "../components/ArticleListComponent";

class ArticleList2 extends React.Component {
  static navigationOptions = {
  title: 'Link2'
  };

  render() {
    return (
      <View>
        <Text>LIst2</Text>
      </View>
    );
  }
}

export default ArticleList2;

但是,标题和标题不会在应用程序中呈现。有人能帮忙吗?