I am working with Expo, React Native and I want to to be able to detect text from images. Is there an package i can work with to achieve this?
I am using Expo camera module to snap the picture and supply the URI to the text detector
I have tried using react-native-text-detector but I am getting the error that the function detectFromUri is not defined. I have also tried with tesserect.js but it fails on import with "unable to resolve variable location".
await this.camera.takePictureAsync(options).then(photo => {
photo.exif.Orientation = 1;
//console.log(photo.uri);
const visionResp = await RNTextDetector.detectFromUri(photo.uri);
if (!(visionResp && visionResp.length > 0)) {
throw "UNMATCHED";
}
console.log(visionResp);
});
I am expecting the visionResp to log the results returned from the detection but instead i get undefined is not an object (evaluating '_reactNativeTextDetector.default.detectFromUri')
Is your project created with expo-cli?
If yes, Expo is not supporting OCR currently. There is a feature request on canny.io but you can't know for sure when it will become available.
Your only choice is to use an OCR service like this one.Internet connectivity will be required.
If not, (and the project is created with react-native-cli) you should be able to successfully use react-native-text-detector. Just make sure you link the package correctly. Docs here
Related
I want to use systemjs inside react-native.
When I use following code in the browser systemjs register itself with global/window.
fetch('https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.18.17/system.src.js')
.then(response => response.text())
.then(txt => {
eval(txt);
})
.catch(ex => {
console.log(ex);
});
I executed same code in expo AwesomeProject on the homescreen component and the above code does not throw any exceptions, but when I try to render all the globally registered objects I don't see SystemJs/System.
First question I have - Is it even possible to register systemjs and use it with react-native?
If the answer to first question is yes, then is it the correct way to eval(Systemjs)?
If not is there any other method I can use to access system js?
I have seen couple of projects on github like react-native-eval and react auto updater, but that is not what I want.
Anyone can give me some insight?
I will answer my own question.
Yes it is possible to load systemjs in React native.
Simple eval will evaluate the systemjs code, but you might get some errors. I am not an expert in the internals of systemjs but it seems it tries to run in some context, either a browser or in some cases a node server.
I received an error in following code.
var vmModule = 'vm';
var vm = require(vmModule);
I had to tweak my code a little bit and supply a fake require function and I was able to load systemjs.
I am having an issue related to react-native-asyncstorage from here:
https://facebook.github.io/react-native/docs/asyncstorage.html
When I run react-native run-ios, the following error appears:
I am using react-native 0.52.0 and this problem may be due to the dependency of react-native-asyncstorage:
react-native-asyncstorage#1.0.0 requires a peer of
react-native#^0.47.2 but none is installed. You must install peer
dependencies yourself.
The odd thing is it works fine for Android, but not for both iOS nor iOS emulator.
Can someone help?
EDIT
I would like to add some points that maybe useful:
I use Expo for development,
I have commented every AsyncStorage in my code, but the problem still persist,
As asked in the comment, here is the snipped code of my AsyncStorage code
-
import { AsyncStorage } from 'react-native';
export async function SetItem(strKey, objValue) {
try {
if (typeof(objValue) === 'string') {
await AsyncStorage.setItem(strKey, objValue);
}
else {
await AsyncStorage.setItem(strKey, JSON.stringify(objValue));
}
}
catch(error){
console.log(error);
}
}
Like said in the documentation: NOTE: This is not supported by all native implementations, you're probably running in an error because of this.
It may also be Reactotron you're using (according to the stack trace) that causes this. Try disabling it at first?
Are you having a custom implementation of AsyncStorage (like: https://www.npmjs.com/package/react-native-asyncstorage)? If so, take it off unless there's a specific reason to use it (please elaborate in the question)
But in general, you could for instance use React Native Simple Store and it's update method.
Or then you could write your own function with lodash.merge.
If problem persists even with commenting out all the AsyncStorage code, removing possible custom dependencies and taking off Reactotron, and you can't find a way to write multiMerge by yourself, update your question and ping me on this answer.
I tried with the npm module react-native-check-app-install but I couldn't achieved always the result is false.
Also tried with react-native-installed-apps to get the list of apps installed in the phone but this return always empty list.
Did you make sure to declare the URL schemes?
https://developers.google.com/maps/documentation/ios-sdk/start#step_6_declare_the_url_schemes_used_by_the_api
Once you've done that, you don't need an additional package to check if you can open Google Maps. You can just use the Linking module.
Linking.canOpenURL('comgooglemaps://?center=40.765819,-73.975866')
.then((canOpen) => {
if (canOpen) { console.log('open google maps'); } else { console.log('open apple maps'); }
});
The problem here is that I need call MercadoPago in mi Application using React-Native, but i can not find the way,
I found this wrapper for use in React-Native,
https://github.com/shovelapps/react-native-mercadopago
but when I am trying to call it I have an error in startCheckOut method,
I am using in this way the Wrapper
import RNMercadopago from 'react-native-mercadopago';
and I am calling the method in a click event using this line:
RNMercadopago.startCheckout(publicKey, prefId, null, false, (payment) => { this._success(payment)}, (error) => { this._failure(error) });
but I am getting the bellow error,
undefined is not an object (evaluating 'RNMercadopago.startCheckout)
all this code is in the index.ios.js
best regards
you may use react-native-mercadopago-checkout. It allows you to implement MercadoPago checkout in two diferent ways (both of them are documented).
It's a new implementation that is working in a production app. Even, if you find a bug, you could open an Issue and be sure that it will be resolved!
I was wondering if there is a way to log the current filename or directory in React Native. Similar to how NodeJS does it with __filename and __dirname.
No, it's not possible since all the source code gets bundled together into one big file, and then a source map is provided so that you can debug it in the original structure.
You can see that by calling this code snippet somewhere in your code:
console.log(new Error().stack);
In a regular javascript you would get the entire trace with files and line numbers, but in react-native you get somthing like:
Error
at Login (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:83009:9)
at instantiate (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:5712:18)
at new Login (eval at proxyClass (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:5730:16), <anonymous>:4:17)
at ReactCompositeComponentWrapper._constructComponentWithoutOwner (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:22051:19)
at ReactCompositeComponentWrapper._constructComponent (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:22033:13)
at ReactCompositeComponentWrapper.mountComponent (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:21952:15)
at Object.mountComponent (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:20425:29)
at ReactCompositeComponentWrapper.performInitialMount (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:22134:28)
at ReactCompositeComponentWrapper.mountComponent (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:22015:13)
at Object.mountComponent (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:20425:29)"
which shows you the real files are gone.