I have a folder called "app" which contains a "views" folder. Inside views I have a "Home.js" file in which I've defined a class component "Home". I want to use the Home class in another file "App.js".
The following code is what's in the Home.js file.
import React from 'react';
import {View, Text} from 'react-native';
export class Home extends React.Component {
render () {
return (
<View>
<Text> Some text </Text>
<Text> Some other random text </Text>
</View>
);
}
}
And this is what's in the App.js file.
import React from 'react';
import { Home } from '.app/views/Home.js';
export default class App extends React.Component {
render () {
return (
<Home />
);
}
}
When I try and run it with expo, I get an error "Error: undefined Unable to resolve module '.app/views/Home.js'"
No matter the path I try to bring Home from, I get the same error, even if I copy and paste the path directly from the Home.js file. I'm curious, I wanna know if this is a code error, or maybe the way I'm bringing up the path is wrong? Any ideas as to how to solve this? Thanks a lot.
You need to get in your folder like this:
'./app/views/Home.js';
Related
I'm trying to style a View in React-native but I keep getting this Error
(undefined is not an object (evaluating 'styles.screen))
I made a simple code ...
import React, {useState} from 'react';
import {StyleSheet, Text, View, Button, TextInput} from 'react-native';
export default function App() {
return (
<View style={styles.screen}>
<Text>I am testing</Text>
</View>
);
const styles = StyleSheet.create({
screen: {
padding: 50,
},
});
}
I spent two hours trying to fix this
This should fix it:
import React, { useState } from 'react';
import { StyleSheet, Text, View, Button, TextInput } from 'react-native';
export default function App() {
return (
<View style={styles.screen}>
<Text>I am testing</Text>
</View>
);
}
const styles = StyleSheet.create({
screen: {
padding: 50,
},
});
You need to move the const styles object outside of your App() function. The way you have it will return before initialising your stylesheet. An alternative is to place it before your return() inside App() but it is more standard to have it outside.
So, after troubleshooting for 3 hours and finding no info on this, I finally have the answer. I used a class template search bar React Native Search Bar and created custom styles for said search bar that was being exported from a file, in a folder named 'components' in a parent folder 'app' that was in my '[project]' folder. I imported the class to each screen as it was a header.
The following was an *incorrect import:
import {SearchComponent} from './app/components/searchComponent'
The correct import is:
import SearchComponent from './app/components/searchComponent'
(Because the SearchComponent was exported as a default component and not a named component in the searchComponent.js file.)
Quick reference to default vs named exports
After correctly importing the component, make sure your styles within that component's folder are named correctly and do not share style names with other styles in your destination file; i.e., name of fileA:styleA != name of fileB:styleA.
After checking your exports and imports very, very carefully and checking your style names with the same detail it worked – and it should work for you, as well.
I have design header, footer video player view, etc as a separate files.
How do I include those in every pages?
I tried this method. but doesn't work.
Follow the below steps:
Create a file eg: Header.js
import React, { Component } from 'react'
import { Text, View } from 'react-native'
class Header extends Component {
render() {
return (
<View>
<Text> Header Component </Text>
</View>
)
}
}
export that component or function to reuse that in other files.
export default Header;
by exporting that function or class you can import that in any js file by using this:
import Header from './Header.js'
OR
import Header from './Header'
Here is how you can use that imported component in other files:
import React, { Component } from 'react'
import { Text, View } from 'react-native'
import Header from './Header' // import that
class App extends Component {
render() {
return (
<View>
<Header /> // use like this
<Text> textInComponent </Text>
</View>
)
}
}
If you have multiple components or function to export in a single file you can't use export default in all of that. you just have to use export only.
like this: Common.js file
export Header;
export Button;
or you can use that like this.
import { Header, Button } from './Common';
I have a react-native app where I have developed a scanner feature using react-native-qrcode-scanner.However, when I try to scan the data, I get the below error-
error: can't find variable navigation
I see this error in onSuccess method at line authorizationToken.
My code-
import React, { Component } from 'react';
import {
Text,
View,
Image,
TouchableOpacity,
Linking
} from 'react-native';
import styles from '../assets/style';
import QRCodeScanner from 'react-native-qrcode-scanner';
export default class ScanScreen extends Component {
onSuccess(scanEvent) {
this.props.navigation.navigate("Result", {
'accessKey': scanEvent.data,
'authorizationToken':navigation.getParam('authorizationToken', undefined),
"userData": navigation.getParam('userData', undefined),
"methodName": "fetchData"
});
}
render() {
return (
<View style={styles.container}>
<QRCodeScanner
onRead={this.onSuccess.bind(this)}
/>
</View>
);
}
}
Any idea what I m missing here. Any help is much appreciated.Thanks in advance.
Make sure that Your Screen is registered in react-navigation config (follow this guide: can't find variable navigation).
Or pass navigation prop to it with HOC withNavigation: https://reactnavigation.org/docs/en/with-navigation.html. Instead export default class ScanScreen extends Component do class ScanScreen extends Component and at end of file do
export default withNavigation(ScanScreen);
Don't forget about importing Higher Order Component: import { withNavigation } from 'react-navigation';
Also be sure that all native parts are properly linked. For example react-native-gesture-handle (https://kmagiera.github.io/react-native-gesture-handler/docs/getting-started.html#linking).
navigation has to be part of props so accessing navigation using this.props.navigation solves this issue.
I'm bizarrely getting an error that a local file import can't be resolved by React Native.
Unable to resolve module `./components/MyComponent" from ".//App.js`: could not resolve `/Users/myusername/Desktop/mylibrary/components/MyComponent' as a file nor as a folder","name":"UnableToResolveError","type":"UnableToResolveError","errors":[{}]},"type":"bundling_error"}"
mylibrary/App.js:
import React from 'react';
import {
View,
Text,
StyleSheet,
ScrollView,
AsyncStorage,
} from 'react-native';
import MyComponent from './components/MyComponent';
mylibrary/components/MyComponent.jsx:
import React from 'react';
import { StyleSheet, Text, View } from 'react-native';
export default class MyComponent extends React.Component {
render() {
<View>
{this.props.children}
</View>
}
}
I tried renaming the file to be lowercase (mycomponent.jsx), and it didn't make a difference. I also tried restarting my simulator and resetting the cache, and it also didn't help.
The import statement by default try to import .js files, try renaming MyComponent.jsx to MyComponent.js.
Quoting the MDN:
The module to import from. This is often a relative or absolute path name to the .js file containing the module, excluding the .js extension. Certain bundlers may permit or require the use of the extension; check your environment. Only single quotes and double quotes Strings are allowed.
The component is wrong. You are not returning anything in the render method. Try this:
render() {
return(
<View>
{this.props.children}
</View>
)
}
So i am stuck in there. I just want to add a but it never renders it.
It renders the "Registered project page".
index.ios.js
import native from './src';
native();
./src/index.js
import { AppRegistry, Text } from 'react-native';
import React, { Component } from 'react';
export default function index() {
class Root extends Component {
render() {
return (
<Text>
Welcome to React Native!
</Text>
);
}
}
AppRegistry.registerComponent('AwesomeProject', () => Root);
}
So it all works great. I can even debug and see that the App component is called etc. But why i never get to render anything except that window ?