不確定是不是（評估「this.props.navigation.navigate」）的對象 - 陣營本地

Question

我試圖讓我的第一陣營原生Android應用程序和我收到此錯誤：

undefined is not an object (evaluating 'this.props.navigation.navigate')

這是代碼：

import React from 'react'; 
import { StyleSheet, Text, View, Button, TextInput } from 'react-native'; 
import { StackNavigator } from 'react-navigation'; 

export default class HomeScreen extends React.Component { 

    static navigationOptions = { 
    title: 'Home', 
    }; 

    render() { 
    const { navigate } = this.props.navigation;  

    return (
     <View> 
     <Button 
      title="Show Centers near me" 
      onPress={() => 
      navigate('Results', "Search Term") 
      } 
      /> 
     <Text>or</Text> 
     </View> 
    ); 
    } 
} 


class ResultsScreen extends React.Component { 

    static navigationOptions = { 
    title: 'Results', 
    }; 


    render() { 
    const { navigate } = this.props.navigation; 

    return (
     <View> 
     <Text>Hi</Text> 
     </View> 
    ); 
    } 
} 

const App = StackNavigator({ 
    Home: { screen: HomeScreen }, 
    Results: { screen: ResultsScreen } 
}); 

我不明白爲什麼錯誤即將到來。

Answer 1

您正在導出組件錯誤。你應該得到你的class HomeScreen定義，並在文件的底部擺脫export default做export default App;