以下是React Native应用程序启动一段时间后的
Android日志输出,然后通过终止Meteor服务器将其与Meteor(DDP)服务器断开连接.
使用console.log(“< App /> render”)来指示何时调用App组件的渲染功能,看起来每当createContainer传递一些新的道具后再次调用渲染函数时,Key就已定义错误被触发.
导致此错误/警告的原因是什么？我们如何解决？该应用仍然运行正常,但这里肯定是错的.
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)
应用组件
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);
解决方法
警告不会造成任何伤害,但您可以通过在变量中定义场景然后将它们作为路径包含在路由器中来解决它们,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} />
)
}
}
有关详细信息,请参阅docs.