8

以下是 React Native 应用程序在通过终止 Meteor 服务器断开与 Meteor (DDP) 服务器连接之前启动一段时间后的 Android 日志输出。

用于console.log("<App /> render")指示何时调用组件的render函数App，似乎每当在传递一些 newrender后再次调用该函数时，都会触发错误。createContainerpropsKey is already defined

是什么导致了这个错误/警告，我们该如何解决？该应用程序仍然运行良好，但这里肯定有问题。

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!

index.android.js

import { AppRegistry } from 'react-native'

import App from './app/App.js'

AppRegistry.registerComponent('RNapp', () => App)

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);
4

2 回答 2

4

警告不会造成任何伤害，但是您可以通过在变量中定义场景然后将它们作为道具包含在路由器中来摆脱它们，如下所示：

const scenes = Actions.create(
  <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>
)

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 scenes={scenes} />
    )
  }

}

有关更多信息，请参阅文档。

于 2017-04-26T21:15:03.967 回答
1

根据我的经验，警告不会引起任何问题，但以防万一，我通常定义一个shouldComponentUpdate方法，如果道具/状态没有以需要更改路由的方式更改，则返回 false（请注意，我使用 redux 和 redux坚持决定什么是初始场景，所以我需要将组件连接到 redux 以便通过 props 获取所需的信息，但稍后如果存储中的数据发生变化，我可以安全地阻止额外的渲染）。

这只是我基于我的经验和需求的方法。router-flux 的家伙对此有一个稍微“更严格”的方法，你可以在他们的文档中看到

于 2016-12-28T07:41:29.930 回答