根据登录状态显示使用React-本机-路由器-Flux的不同组件。

Question

我的应用程序使用react-native-router-flux来决定向用户显示哪个组件取决于用户是否是

• 登录，或等待应用程序连接到后端(显示<Loading />__)
• 登录(显示<Home />__)
• 未登录(显示<Welcome />__)

实现这一目标的推荐方法是什么？

这个示例工作得很完美，只是它不使用react-native-router-flux。无论如何，要修改代码以使用react-native-router-flux

在下面的尝试中，在调用Actions.loading()函数之前调用render会产生一个错误，因为Actions还没有定义。if语句可以在render函数之后调用吗？

此外，每次更新道具时，都会导致App的重呈现，从而给出场景键已经存在的错误。

import React, { Component } from 'react';
import Meteor, { createContainer } from 'react-native-meteor';
import { Actions } from 'react-native-router-flux';

import Home from './components/home';
import Welcome from './components/welcome';
import Loading from './components/loading';
import settings from './config/settings';


Meteor.connect(settings.METEOR_URL);


const App = (props) => {

    const { status, user, loggingIn } = props;

    if (status.connected == false || loggingIn) {
        // Render <Loading />
        Actions.loading();
    } else if (user !== null) {
        // Render <Home />
        Actions.home();
    } else {
        // Render <Welcome />
        Actions.welcome();
    }

    return (
        <Router>
            <Scene key="root">
                <Scene key="home" component={Home} title="Home" hideNavBar={true} />
                <Scene key="welcome" component={Welcome} title="Welcome" hideNavBar={true} />
                <Scene key="loading" component={Loading} title="Loading" hideNavBar={true} />
            </Scene>
        </Router>
    )
}


export default createContainer(() => {
    return {
        status: Meteor.status(),
        user: Meteor.user(),
        loggingIn: Meteor.loggingIn()
    };
}, App)

使用Dispatch组件时遇到的问题

根据abeikverdi的建议，我创建了下面的Dispatch组件，其中包含用于显示组件<Loading />、<Home />或<Welcome />之一的逻辑。

问题：当this.props.status.connected是true ( receives连接到Meteor )时，this.props.user在从Meteor后端接收数据之前一直是null。但是，由于它最初被计算为null，所以Action.welcome()将执行。这种行为是不正确的，当this.props.user最终在一两秒钟后不是null时，用户应该被重定向到Actions.home()。

有什么想法吗？

export class Dispatch extends Component {
    constructor(props) {
        super(props);
    }

    componentWillUpdate() {
        if(this.props.status.connected == false) {
            Actions.loading();
        } else {
            console.log('meteor.user(): ', Meteor.user())
            if (this.props.user !== null) {
                Actions.home();
            } else {
                Actions.welcome();
            }
        }
    }

    render() {
        return (
            <View></View>
        )
    }
}


export default createContainer(() => {
    return {
        status: Meteor.status(),
        user: Meteor.user(),
        loggingIn: Meteor.loggingIn()
    };
}, Dispatch);

来自日志react-native log-android的错误/警告

下面是在通过关闭Meteor服务器将其与Meteor (DDP)服务器断开连接之前启动React一段时间后的Android日志输出。

使用console.log("<App /> render")时，每当render函数在Meteor的createContainer传递新的props后再次调用，就会触发Key is already defined错误。

不管怎么说，为了消除这个错误/警告？

12-23 02:27:01.875 31197 19338 I ReactNativeJS: Running application "RNapp" with appParams: {"initialProps":{},"rootTag"
:1}. __DEV__ === true, development-level warning are ON, performance optimizations are OFF
12-23 02:27:01.891 31197 19338 I ReactNativeJS: render
12-23 02:27:01.995 31197 19338 I ReactNativeJS: Connected to DDP server.
12-23 02:27:01.999 31197 19338 I ReactNativeJS: Connected to DDP server.
12-23 02:27:02.012 31197 19338 I ReactNativeJS: render
12-23 02:27:02.013 31197 19338 I ReactNativeJS: Key home is already defined!
12-23 02:27:02.013 31197 19338 I ReactNativeJS: Key welcome is already defined!
12-23 02:27:02.013 31197 19338 I ReactNativeJS: Key loading is already defined!
12-23 02:27:02.013 31197 19338 I ReactNativeJS: Key root is already defined!
12-23 02:27:34.592 31197 19338 I ReactNativeJS: Disconnected from DDP server.
12-23 02:27:34.593 31197 19338 I ReactNativeJS: Disconnected from DDP server.
12-23 02:27:34.599 31197 19338 I ReactNativeJS: <App /> render
12-23 02:27:34.599 31197 19338 I ReactNativeJS: Key home is already defined!
12-23 02:27:34.599 31197 19338 I ReactNativeJS: Key welcome is already defined!
12-23 02:27:34.599 31197 19338 I ReactNativeJS: Key loading is already defined!
12-23 02:27:34.599 31197 19338 I ReactNativeJS: Key root is already defined!
12-23 02:27:34.609 31197 19338 I ReactNativeJS: <Loading /> render
12-23 02:27:35.603 31197 19338 I ReactNativeJS: Disconnected from DDP server.
12-23 02:27:35.613 31197 19338 I ReactNativeJS: <App /> render
12-23 02:27:35.613 31197 19338 I ReactNativeJS: Key home is already defined!
12-23 02:27:35.613 31197 19338 I ReactNativeJS: Key welcome is already defined!
12-23 02:27:35.613 31197 19338 I ReactNativeJS: Key loading is already defined!
12-23 02:27:35.613 31197 19338 I ReactNativeJS: Key root is already defined!
12-23 02:27:45.599 31197 19338 I ReactNativeJS: Disconnected from DDP server.
12-23 02:27:45.616 31197 19338 I ReactNativeJS: <App /> render
12-23 02:27:45.616 31197 19338 I ReactNativeJS: Key home is already defined!
12-23 02:27:45.616 31197 19338 I ReactNativeJS: Key welcome is already defined!
12-23 02:27:45.616 31197 19338 I ReactNativeJS: Key loading is already defined!
12-23 02:27:45.616 31197 19338 I ReactNativeJS: Key root is already defined!

App 组件

export class App extends Component {

    constructor(props) {
        super(props);
    }

    componentWillReceiveProps(nextProps) {
        if (nextProps.status.connected == false) {
            Actions.loading();
        } else {
            if (nextProps.user !== null) {
                Actions.home();
            } else {
                Actions.welcome();
            }
        }
    }


    render() {
       console.log('<App /> render')
        return (
            <Router>
                <Scene key="root">
                    <Scene key="home" component={Home} title="Home" hideNavBar={true} />
                    <Scene key="welcome" component={Welcome} title="Welcome" hideNavBar={true} />
                    <Scene key="loading" component={Loading} title="Loading" hideNavBar={true} />
                    <Scene key="profile" component={Profile} title="Home" hideNavBar={true} />
                    <Scene key="history" component={History} title="Home" hideNavBar={true} />
                    <Scene key="search" component={Search} title="Home" hideNavBar={true} />
                </Scene>
            </Router>
        )       
    }

}


export default createContainer(() => {
  return {
    status: Meteor.status(),
    user: Meteor.user(),
    loggingIn: Meteor.loggingIn(),
  };
}, App);

Answer 1

您可以通过使用初始支持来实现这一点，您可以从存储中读取数据，这些数据将指示用户是否登录，例如使用access_token。

然后使用initial={access_token} //，例如

但请记住，它将显示最后一幕与初始道具相等于真

// in componentDidMount
const currentUserAccessToken = store.getState().currentUserAccessToken;
        <Scene
            component={SignIn}
            hideNavBar
            initial={!currentUserAccessToken}
            key="signIn"
            title={I18n.t('sign_in')}
        />

Answer 2

您可以创建一个调度页面，并将您的逻辑放在那里。因此，只需添加调度作为一个场景，然后导航从那里。

return (
        <Router>
            <Scene key="root">
                <Scene key="dispatch" component={Dispatch} hideNavBar={true} initial={true} />
                <Scene key="home" component={Home} title="Home" hideNavBar={true} />
                <Scene key="welcome" component={Welcome} title="Welcome" hideNavBar={true} />
                <Scene key="loading" component={Loading} title="Loading" hideNavBar={true} />
            </Scene>
        </Router>
    )

更新：

似乎流星正在把这些论点传递给道具。一旦添加了新的道具，componentWillUpdate()就不会被触发。相反，您应该将导航逻辑放在Actions中的componentWillReceiveProps(nextProps)中，如下所示：

componentWillReceiveProps(nextProps) {
    if(nextProps.status.connected == false) {
        Actions.loading();
    } else {
        console.log('meteor.user(): ', Meteor.user())
        if (this.props.user !== null) {
            Actions.home();
        } else {
            Actions.welcome();
        }
    }
}

然后，您的导航逻辑应该在您的登录功能完成后触发。这应该能起作用。