Navigation 跳转报错

[guohongqi-china]

按照 官方文档写的 Navigation 跳转的方法为什么，跳转时报错？如下：

import React, { Component } from 'react';
import {
AppRegistry,
StyleSheet,
Text,
View,
Button
} from 'react-native';

import { StackNavigator } from 'react-navigation';
// import { ChatScreen } from 'ChatScreen';

class HomeScreen extends React.Component {

constructor(props){
super(props);

}

static navigationOptions = {
    title: 'Welcome',
}




render() {
    const { navigate } = this.props.navigation;
    return (
        <View>
          <Text>Hello, Chat App!</Text>
          <Button
              onPress={() => navigate('Chat')}
              title="Chat with Lucy"
          />
        </View>
    );
}

}

class ChatScreen extends React.Component {
static navigationOptions = {
title: 'Chat with Lucy',
};
render() {
return (
<View>
<Text>Chat with Lucy</Text>
</View>
);
}
}

const WOHaoLe = StackNavigator({
Home: { screen: HomeScreen },
Chat: { screen: ChatScreen },
});

AppRegistry.registerComponent('WOHaoLe', () => WOHaoLe);