我的应用程序react-native-router-flux
用于根据用户是否是来决定向用户显示哪个组件
- 登录,或等待应用连接到后端(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?
这个例子完美无缺,只是它没有使用react-native-router-flux
. 无论如何修改代码以使用react-native-router-flux
?
在我下面的尝试中,在调用函数Actions.loading()
之前render
调用会产生错误,因为Actions
尚未定义。if
语句可以在函数之后调用render
吗?
此外,每次更新道具时,都会导致重新渲染App
,从而给出有关场景键如何存在的错误。
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
组件的问题
根据 abeikverdi 的建议,我创建了以下Dispatch
组件,其中包含显示组件之一的逻辑<Loading />
,<Home />
或<Welcome />
。
问题:this.props.status.connected
什么时候true
(React Native 应用程序连接到 Meteor 后端),this.props.user
总是null
在 React Native 应用程序从 Meteor 后端接收到此数据之前一段时间。但是因为它最初被评估为null
,所以Action.welcome()
会被执行。this.props.user
当最终null
在一两秒后变为不并且用户应该被重定向到而不是时,这种行为是不正确的Actions.home()
。
有任何想法吗?
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);
来自日志的错误/警告react-native log-android
以下是 React Native 应用程序在通过终止 Meteor 服务器断开它与 Meteor (DDP) 服务器之前启动一段时间后的 Android 日志输出。
使用console.log("<App /> render")
,似乎每当在被Meteorrender
传递 new 后再次调用该函数时,都会触发错误。props
createContainer
Key is already defined
无论如何要摆脱这个错误/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
零件
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);