I have use react-native, the version is "version": "0.57.1". I have installed react-navigation via:
npm install --save react-navigation
The react-navigation version is react-navigation#3.4.0. The content of app.js file is below:
import * as React from 'react';
import { Text, View } from 'react-native';
// import { createStackNavigator } from 'react-navigation';
class HomeScreen extends React.Component {
render() {
return (
<View style={{ flex: 1, alignItems: "center", justifyContent: "center" }}>
<Text>Home Screen</Text>
</View>
);
}
}
export default HomeScreen;
This sample works fine on expo. But when I run third line, an error occurs.
[16:57:50] While trying to resolve module react-navigation from file
/home/ubuntu/workspace/App.js, the package
/home/ubuntu/workspace/node_modules/react-navigation/package.json
was successfully found. However, this package itself specifies a
main module field that could not be resolved
(/home/ubuntu/workspace/node_modules/react-navigation/src/react-navigation.js.
Indeed, none of these files exist: [16:57:50] [16:57:50] *
/home/ubuntu/workspace/node_modules/react-navigation/src/react-navigation.js(.native||.android.js|.native.js|.js|.android.json|.native.json|.json|.android.ts|.native.ts|.ts|.android.tsx|.native.tsx|.tsx)
[16:57:50] *
/home/ubuntu/workspace/node_modules/react-navigation/src/react-navigation.js/index(.native||.android.js|.native.js|.js|.android.json|.native.json|.json|.android.ts|.native.ts|.ts|.android.tsx|.native.tsx|.tsx)
This is odd you should not need to install react navigation specifically this should be installed automatically when making an expo project I would recommend deleting your node-modules and installing again with the following
rm -rf node_module && npm install
npm audit fix
expo start
If this doesn’t do the trick try making a new project and just copy your class to it hope this helps
I'm using the example found here & currently facing issue with the toast not showing at all... I just have the initial 'Welcome to React Native!' screen in the emulator. My app structure is as follows:
testApp
android
app
src
main
java
com
testApp
CustomToastPackage.java
MainActivity.java
MainApplication.java
ToastModule.java
res
assets
index.android.bundle
AndroidManifest.xml
ios
node_modules
app.json
App.js
index.js
package.json
ToastExample.js
yarn.lock
My index.js
import {AppRegistry} from 'react-native';
import App from './App';
import {name as appName} from './app.json';
import {NativeModules} from 'react-native'; //Added this
module.exports = NativeModules.testApp; //Added this
AppRegistry.registerComponent(appName, () => App);
My App.js
import React, {Component} from 'react';
import {Platform, StyleSheet, Text, View} from 'react-native';
import ToastExample from './ToastExample'; //Added this
const instructions = Platform.select({
ios: 'Press Cmd+R to reload,\n' + 'Cmd+D or shake for dev menu',
android:
'Double tap R on your keyboard to reload,\n' +
'Shake or press menu button for dev menu',
});
type Props = {};
export default class App extends Component<Props> {
render() {
return (
<View style={styles.container}>
<Text style={styles.welcome}>Welcome to React Native!</Text>
<Text style={styles.instructions}>To get started, edit App.js</Text>
<Text style={styles.instructions}>{instructions}</Text>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#F5FCFF',
},
welcome: {
fontSize: 20,
textAlign: 'center',
margin: 10,
},
instructions: {
textAlign: 'center',
color: '#333333',
marginBottom: 5,
},
});
As you can see from the file structure I created an additional file named ToastExample.js that contains following based upon the answer found here
import {NativeModules} from 'react-native';
module.exports = NativeModules.ToastExample;
Package name is simply
com.testapp
I can't figure out why the toast never shows? I know react comes with toast support but looking to build upon an initial example to include more advanced Java/Android code...
In your example you didn't add ToastExample in index.js you need to add this into rendering method in index.js like below.
return(
<ToastExample/>
)
In addition to that, you are going to create an android native module which can be used only for android.
But According to my point of view, you can use toast messages module which can be used in both Android and Ios. Otherwise, you need to create ios base native module for creating toast for ios. If u don't want to ios base implementation, it's ok to use this native module. But you block your Ios deployment by it.
I would like to suggest this https://github.com/crazycodeboy/react-native-easy-toast#readme
easy-toast for u. It will work on both Android and IOS devices. You can customize it like android native toast as well. It is easy to implement in your application.
Thanks #Ariel & #Lucefer for feedback, I made the update you suggested but ran into another error. Posting this answer to save anyone potential headache caused by using Android Studio as IDE with React Native. Turns out the MainApplication.java file had 2 items (import of CustomToastPackage & ReactPackage) greyed out & could never figure out why? See the screenshot below
I created a separate application (react-native init newapp) & used a simple text editor (Atom or gedit will do instead of Android Studio) to make the changes & the example runs just fine now.
try this:
<Root>
<View style={styles.container}>
<Text style={styles.welcome}>Welcome to React Native!</Text>
<Text style={styles.instructions}>To get started, edit App.js</Text>
<Text style={styles.instructions}>{instructions}</Text>
</View>
</Root>
just import Root to react native
I am developing Android app using React Native. I tried running a simple code of a screen being displayed, but I get the following error. I tried closing all command line windows and emulator and re-starting React Native package and run it, but doesn't work. The code is provided below:
index.android.js:
import React, { Component} from 'react';
import {Text, View, AppRegistry,Button} from 'react-native';
import {StackNavigator} from 'react-navigation';
import dhrumil from '.\dhrumil.js';
export default class MainApp extends Component{
render(){
return(
<dhrumil />
);
}
}
const SimpleApp = StackNavigator({
Home: {screen: dhrumil }
});
AppRegistry.registerComponent("MainApp",()=>SimpleApp);
dhrumil.js:
import React, { Component} from 'react';
import {Text, View, AppRegistry,Button,StyleSheet} from 'react-native';
const dhrumil = () =>{
return(
<View style={styles.container}>
<Text style={styles.texter}>Hello World!</Text>
<Button
onPress={() => navigate('dharmin')}
title="Chat with Lucy"
/>
</View>
);
}
const styles = StyleSheet.create({
container:{
justifyContent: 'center',
alignItems: 'center',
flex: 1
}
texter:
{
fontSize: 20,
textAlign: 'center'
}
});
dhrumil.navigationOptions = {
title:'dhrumil'
}
export default dhrumil
How do I solve this?
In index.android.js change the import dhrumil from '.\dhrumil.js'; to import dhrumil from './dhrumil';. You have to use / to specify the path and it is not necessary use dhrumil.js when we are importing the js file.
#Jeffrey Rajan 's suggestion was absolutely correct here.
This error occurs mostly due to :
Issue 1:
A wrong file name in import statement
Using the wrong case in file name
Using '\' instead of '/' in file name
Hope that using this list you can easily find errors causing this in your code.
Issue 2:
An issue with the material design.To resolve this install material design locally using :
react-native-material-design
Issue 3:
babel-preset-react-native making trouble code. To resolve this issue run:
yarn remove babel-preset-react-native
yarn add babel-preset-react-native#2.1.0
Try troubleshooting in this order.Mostly the Issue 1 will solve the problem.
I am working on a sample react native project. And almost all features except the <Image source=''/> work well with it. The image shows well in android emulator supplied with android studio and genymotion, but does not work on any real devices (moto G3 turbo, nexus 5, galaxy s4 etc...). I don't know what went wrong with my code. Here is my code
import React, { Component } from 'react';
import {
AppRegistry,
StyleSheet,
Text,
View,
Image
} from 'react-native';
class ImageTester extends Component {
render() {
return (
<View style={styles.container}>
<Text style={styles.welcome}>
Welcome to React Native!
</Text>
<Text style={styles.instructions}>
To get started, edit index.android.js
</Text>
<Text style={styles.instructions}>
Double tap R on your keyboard to reload,{'\n'}
Shake or press menu button for dev menu
</Text>
<Image source={require('./img/first_image.png')}></Image>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#F5FCFF',
},
welcome: {
fontSize: 20,
textAlign: 'center',
margin: 10,
},
instructions: {
textAlign: 'center',
color: '#333333',
marginBottom: 5,
},
});
AppRegistry.registerComponent('ImageTester', () => ImageTester);
project structure:
React-native version : react-native: 0.32.1
The problem was with my bundle packaging command. As #luwu said in his comment, I checked this, and surprised that there is no difference with mine. Then only I noticed a message while running the command
"Assets destination folder is not set, skipping..."
That message was bit confusing since bundle was already created in the assets folder. The 'Assets' in that messages actually indicates my images. And I solved the issues with the following command:
react-native bundle --platform android --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --dev false --reset-cache --assets-dest android/app/src/main/res/
Another solution for the same issue of assets not bundled in development.
Add the following line to your app/build.gradle file in the section project.ext.react:
project.ext.react = [
... other properties
bundleInDebug: true // <-- add this line
]
From the docs in the starter project gradle file:
By default, bundleDebugJsAndAssets is skipped, as in debug/dev mode we prefer to load the bundle directly from the development server.
i had the same issue. turns out i had import image component from react-native-elements instead of rect-native.fixed my case
I was having a similar issue on my project. My problem was that the Image is displaying ok on iOS but not showing on android (devices).
So my issue got fixed by adding the following header to my Image:
<Image
source={{
uri: 'https://imageurladdress/img.png',
headers: {
Accept: '*/*',
},
}}
style={styles.imageStyle}
/>
So, for some reason the iOS was already working without the need to add this header in the request. But the point is that after add the headers field, the Image is showing correct on both iOS and android devices.
In my case two things were causing problems
First
I run my backend at http://localhost:3000 and any image asset would have URI similar to
http://localhost:3000/rails/active_storage/blobs/redirect/eyJfcmFpbHMiOns
but the android simulator exposes it as
http://10.0.2.2:3000/.....
So http://localhost:3000 is inaccessible in simulator. So I made sure appropriate host is set from backend looking which device is requesting the API.
Second
In params supplied to <Image> component, I used url key(property) which was working fine in IOS but I needed to change it to uri for android.
What helped me personally (none of the solutions here worked) is opening external image from the https://.... and it worked. So I decided to give a try to use 'file://' + DocumentDirectoryPath + '/' + item.image and it worked.
I'm currently trying to get the ES6 react-native-webpack-server running
on an Android emulator. The difference is I've upgraded my package.json and build.grade to use react 0.18.0, and am getting this error on boot. As far as I'm aware AppRegistry is imported correctly. Even if I were to comment out the code this error still comes up. This does work on iOS without issue.
What am I doing wrong?
EDIT: After trying other boilerplates that do support 0.18.0, I'm still coming across the same issue.
i just upgraded to react-native 0.18.1 today tough having some peer dependencies issues with 0.19.0-rc pre-release version.
Back to your question, what I did was
cd android
sudo ./gradlew clean (more information about how clean works here)
then back to the working directory and run
react-native run-android
you should restart your npm too after that upgrade.
hope this works for you.
I had the same issue on iOS and the cause for me was that my index.ios.js was incorrect (because I copy-pasted one of the examples without looking at its contents), it was ending with a module export declaration
exports.title = ...
exports.description = ...
module.exports = MyRootComponent;
Instead of the expected
AppRegistry.registerComponent('MyAppName', () => MyRootComponent);
You could have the same issue on android with the index.android.js I guess.
The one main reason of this problem could be where you would have installed a plugin and forget to link it.
try this:
react-native link
Re-run your app.
Hope this will help. Please let me know in comments. Thanks.
For me just restarting the computer fixed it.
(My error was "module appRegistry is not a registered callable module (calling runapplication) js engine: hermes")
Another top answer that is missing here and might have worked was just to kill node processes:
killall -9 node
[ Module AppRegistry is not registered callable module (calling runApplication) ]
I solved this issue just by adding
import { AppRegistry } from "react-native";
import App from "./App";
import { name as appName } from "./app.json";
AppRegistry.registerComponent(appName, () => App);
to my index.js
make sure this exists in your index.js
For me my issue was putting the wrong entry-file when bundling.
I was using App.js as my entry-file, hence the App couldn't find AppRegistry
Correct:
react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res/
Incorrect:
react-native bundle --platform android --dev false --entry-file App.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res/
I had this issue - across iOS & Android, developing on Mac - after I had been fiddling with a dependency's code in the node_modules dir.
I solved it with:
rm -rf node_modules
npm i
npx pod-install ios
Which basically just re-installs your dependencies fresh.
Hopefully this can save someone a headache. I got this error after upgrading my react-native version. Confusingly it only appeared on the android side of things.
My file structure includes an index.ios.js and an index.android.js. Both contain the code:
AppRegistry.registerComponent('App', () => App);
What I had to do was, in android/app/src/main/java/com/{projectName}/MainApplication.java, change index to index.android:
#Override
protected String getJSMainModuleName() {
return "index.android"; // was "index"
}
Then in app/build/build.gradle, change the entryFile from index.js to index.android.js
project.ext.react = [
entryFile: "index.android.js" // was index.js"
]
If you are facing this error in windows with android
open your root directory app folder and move into android folder .
cd android
gradlew clean
start your app again
react-native run-android
I don't know why, but when I move AppRegistry.registerComponent from the index.js file that is included in index.android.js to reside inside index.android.js directly, it seems to work.
restart packager worked for me.
just kill react native packager and run it again.
Check to see if you are not directly rendering something inside SafeAreaView
Ensure you are following this format
<SafeAreaView>
<View>
{children}
</View>
</SafeAreaView>
If you are using some of the examples they might not work
Here is my version for scroll view
/**
* Sample React Native App
* https://github.com/facebook/react-native
*/
import React, {
AppRegistry,
Component,
StyleSheet,
Text,
View,
ScrollView,
TouchableOpacity,
Image
} from 'react-native';
class AwesomeProject extends Component {
render() {
return (
<View>
<ScrollView
ref={(scrollView) => { _scrollView = scrollView; }}
automaticallyAdjustContentInsets={false}
onScroll={() => { console.log('onScroll!'); }}
scrollEventThrottle={200}
style={styles.scrollView}>
{THUMBS.map(createThumbRow)}
</ScrollView>
<TouchableOpacity
style={styles.button}
onPress={() => { _scrollView.scrollTo({y: 0}); }}>
<Text>Scroll to top</Text>
</TouchableOpacity>
</View>
);
}
}
var Thumb = React.createClass({
shouldComponentUpdate: function(nextProps, nextState) {
return false;
},
render: function() {
return (
<View style={styles.button}>
<Image style={styles.img} source={{uri:this.props.uri}} />
</View>
);
}
});
var THUMBS = [
'http://loremflickr.com/320/240?random='+Math.round(Math.random()*10000) + 1,
'http://loremflickr.com/320/240?random='+Math.round(Math.random()*10000) + 1,
'http://loremflickr.com/320/240?random='+Math.round(Math.random()*10000) + 1
];
THUMBS = THUMBS.concat(THUMBS); // double length of THUMBS
var createThumbRow = (uri, i) => <Thumb key={i} uri={uri} />;
var styles = StyleSheet.create({
scrollView: {
backgroundColor: '#6A85B1',
height: 600,
},
horizontalScrollView: {
height: 120,
},
containerPage: {
height: 50,
width: 50,
backgroundColor: '#527FE4',
padding: 5,
},
text: {
fontSize: 20,
color: '#888888',
left: 80,
top: 20,
height: 40,
},
button: {
margin: 7,
padding: 5,
alignItems: 'center',
backgroundColor: '#eaeaea',
borderRadius: 3,
},
buttonContents: {
flexDirection: 'row',
width: 64,
height: 64,
},
img: {
width: 321,
height: 200,
}
});
AppRegistry.registerComponent('AwesomeProject', () => AwesomeProject);
I uninstalled it on Genymotion. Then run react-native run-android to build the app. And it worked. Do try this first before running sudo ./gradlew clean, it will save you a lot of time.
npm start -- --reset-cache
Probably port is already in use. I face similar issue when i first run react-native run-android and then npm start. I solve it like this: First, get the id of the process running in port 8081:
sudo lsof -i :8081
I had the same problem several times. The following solutions are solved my problem. I have listed out them according to complexity.
Restart the computer and see whether the problem is out
If it still exists, try to kill the process on running port usually 8080
netstat -ano | findstr 8080
taskkill /F /PID <PID>
If it still exists, go to 'android' directory as follow and go further
cd android
./gradlew clean
and start node
npm start
then run npx react-native run android or expo stat and press 'a'
Hope you will OK with the above issues.
My issue was cleared by following these commands (OS: Windows 10).
cd android
gradlew clean
cd..
npx react-native run-android
Please use Below mention : pakage
"react-native-reanimated": "^2.2.4",
I had the same problem and that because I was calling Stylesheet without importing..
In my case, my index.js just points to another js instead of my Launcher js mistakenly, which does not contain AppRegistry.registerComponent().
So, make sure the file yourindex.jspoint to register the class.
My issue was fixed by increasing my inotify max_user_watches:
sudo sysctl fs.inotify.max_user_watches=1280000
For me it was a issue with react-native dependency on next version of react package, while in my package.json the old one was specified. Upgrading my react version solved this problem.
For me just i linked with react native as this way : react-native link
I got this error in Expo because I had exported the wrong component name, e.g.
const Wonk = props => (
<Text>Hi!</Text>
)
export default Stack;
I solved this problem by doing the following:
cd android
./gradlew clean
taskkill /f /im node.exe
uninstall app from android
If you are using windows machine you need to do cd android then ./gradlew clean then run react-native run-android
This can because of any cache issue from node, pod ,gradle anywhere, its better to do an entire clean slate cleanup, for this use react native clean project
A typical reason I get this error is when I import badly a component (like with the wrong name). Same if I export it badly and them import it correctly. This may seem primitive but to err is human and many times this error appears, if cleaning the project and restarting it doesn't fix it, it can be this.
delete android/.gradle and reac-module.
than run yarn install and run-android
on iOS I have got this issue.
but after cleaning the build
folder by entering command+shift+k and building it again worked for me
you should also check the scheme should be debug