無法獲得反應導航工作：`元素類型無效'

Question

我無法獲得反應導航工作的示例。我總是最後的室內用錯誤Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: object. You likely forgot to export your component from the file it's defined in.

這是通過使用從intro page

import React from 'react'; 
import { 
    AppRegistry, 
    Text, 
} from 'react-native'; 
import { StackNavigator } from 'react-navigation'; 

class HomeScreen extends React.Component { 
    static navigationOptions = { 
    title: 'Welcome', 
    }; 
    render() { 
    return <Text>Hello, Navigation!</Text>; 
    } 
} 

const SimpleApp = StackNavigator({ 
    Home: { screen: HomeScreen }, 
}); 

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

我建立適用於iOS和設備（不是模擬器）上運行的例子。

Answer 1

我想你錯過出口的主屏幕類：

class HomeScreen extends React.Component { 

與

export default class HomeScreen extends React.Component {