React Native - 渲染没有返回任何内容

问题描述

我的应用程序存储在/src/index.js 但我也有一个/App.js 和一个/index.js.

My application is stored in /src/index.js but i also have a /App.js and a /index.js.

我不知道这些之间的区别，我认为这就是我收到此错误的原因.

I don't know the difference between these and i think thats the reason im getting this error.

/index.js

import { AppRegistry } from 'react-native';
import App from './App';
AppRegistry.registerComponent('client', () => App);

/App.js

import App from './src/index';

export default App;

/src/index.js

import React from 'react';
import { AppRegistry } from 'react-native';
import { Provider, connect } from 'react-redux';
import { addNavigationHelpers } from 'react-navigation';

import Navigator from './routes/route';
import store from './store/configureStore';


const App = ({ dispatch, nav }) => {

    <Navigator
        navigation={addNavigationHelpers({
            dispatch,
            state: nav,
        })}
    />
};

const mapStateToProps = state => ({
    nav: state.nav,
});



const AppWithNavigation = connect(mapStateToProps)(App);

export default () => {

    <Provider store={store}>
        <AppWithNavigation />
    </Provider>

}

我使用 create react native package 来构建这个项目，然后尝试按照一些指南使用 redux 实现 react 导航.

I used create react native package to build this project and then tried to follow some guides to implement react navigation with redux.

推荐答案

您的默认导出不返回任何内容:

Your default export is not returning anything :

export default () => {

    <Provider store={store}>
        <AppWithNavigation />
    </Provider>

}

要返回带有箭头函数的 JSX，您需要使用 () =>( <JSX/> ) 或带有花括号的等效项: () =>{ return ( <JSX/> ) } :

To return JSX with an arrow function you need to use () => ( <JSX /> ) or the equivalent with curly braces : () => { return ( <JSX /> ) } :

export default () => (
    <Provider store={store}>
        <AppWithNavigation />
    </Provider>
)

或:

export default () => {
    return (
       <Provider store={store}>
           <AppWithNavigation />
       </Provider>
   )
}

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