I have spent all day on this, so if there's an answer, I cannot find it.
Task: use react-native-sqlite-storage to open a pre-populated database in a Windows React Native program.
Problem: No matter where I put the file, the program can't find it.
I am currently using openDatabase('test.db', location: 'default', createFromLocation: 1) as my call. This works fine on Android.
From looking at the repo (line 533), I can see that it needs to end up at "ms-appx:///www/", but how on earth do I get it there???
I am currently using VSCode, in case that has anything to do with it.
Related
I want to change my default icon's app to another one and generate my standalone app (with expobuild:android)
But when I add another image(capture) in my assets folder and replace it in app.js,it gives me an error:
{
"expo": {
"icon": "./assets/capture.png",
}}
I tried many time with and without default icon (I have error just with new image) so i'm sure that error came from the change of icons.
Do you have any idea ;
if you are using a CRNA solution, there is an easy way you can do it. Just go into the /assets folder and just paste there your new icon, then rename it to icon.png, just make sure you already removed the default one. It also works with the splash screen.
But if you created your project with create-react-native-app, you need to do it separatly in Android studio for Android and Xcode for iOS. See more with this link wich helped me too.
https://aboutreact.com/react-native-change-app-icon/
Hope it's gonna help ... Regards
I used this this repo and cloned it, then run one line command to resize the png to all the different formats.
bash resize.sh my-cool-new-app-logo.png
Then drag the folder over and merge/replace icons.
quick insight
we working with expo and using mapview, however, there are many restrictions in react native maps, as we are planning to implement turn by turn navigation. Integrating Mapbox would have been the best option, however we do not think it’s best to eject the project as expo doesn’t still support Mapbox. Although, I came across a package, react native maps navigation, I would like to know if anyone has been able to successfully implement it in their project and it functioned properly, and also know if there are any drawbacks that comes along with it. I am asking this because the author says “Please note that this module is usable but still under heavy development. Some properties and/or component names might change without notice.”
Kindly give your suggestions and advice. Thanks
Mapbox works very well in a react-native projects and recommend to use this service for your project but effectively, it don't works with expo so for me, you should eject your project to use it.
I paste here some packages I used for a GPS project (The last one is to get the current position of an user)
react-native-mapbox-gl/maps
mapbox-sdk
react-native-geolocation
Hope that could help you
I'm making my first react native project, and I've used the create-react-native-app command to get everything set up. However, when I try to get an image to show up in Expo, it gives me an error message that it can't find the png file. I currently have the file under './img/record_video.png' (it's just an icon I'm going to use as a button).
Here's my project layout and the code I'm using to call it
That is, I'm using <Image source={require('./img/record_video.png')} /> in order to call that file.
This is the error message I receive on my phone from the Expo app In short it says undefined Unable to resolve module './img/record_video.png' from C:\Users\ddude\Desktop\AwesomeProject\App.js':The module './img/record_video.png' could not be found from 'C:\Users\ddude\Desktop\AwesomeProject\App.js'. Indeed, none of these files exist:
*'record_video.png'
*'C:\Users\ddude\Desktop\AwesomeProject\img\record_video.png\index(.native||.android.js|.native.js|.js|.android.json|.native.json|.json)'
I'm not sure if it's that I'm using Expo and that it's not exporting to the phone properly, or if it needs to be in a specially-named folder. Any help would be appreciated, thanks!
remove the underscore & rename image assets to record-video.png, record-voice.png and convert-to-text.png. Restart the package manager and try.
Just another observation I do not see an image record_audio.png in img folder
as required in second line.
Hopefully it helps.
I tried react native code push and it works flawlessly. Let's say I modify the text in my buttons to say something else, then with a single command, the update is sent to the users.
Now, lets say I am using a new npm library which requires some native code. Say react-native-image-picker (https://github.com/react-community/react-native-image-picker). Can code push handles this? I want the image picker functionality to be updated too in my users app. Thank you.
No - CodePush can only update JavaScript code and images.
CodePush does not update native code at all so any changes to native code require a full app build and deploy via the relevant app store or app distribution tool (e.g. HockeyApp).
Note: There are some limitations around images - full details here.
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Can someone explain how react native works?
Found a lot of good articles about getting started, components usage, exporting modules.. but,
Googling about how react native works doesn't really help, but this article http://tadeuzagallo.com/blog/react-native-bridge that explains how native modules are exported and what happens when javascript calls them.
.. Still I find it difficult to understand (as a javascript dev) things like,
how first render happens on the screen, what are the functions of those 3 threads and how they communicate with each other, what is this javascript event loop, why do we need batched calls and how it is batched, etc..,
Can someone share an article/explain it in a javascript developer perspective?
thanks!
I will try to describe how React Native works. It's a bit complicated.
And first of all I will like to recommend this URL to learn about basics internal mechanism of React Native:
Read: https://www.reactnative.guide/3-react-native-internals/3.1-react-native-internals.html
So you are writing code in JS/JSX (JavaScript) or TS/TSX (TypeScript) but Android uses primarily Java (for sake of this answer, we know it's Kotlin now) and iOS use Swift/Objective-C so how the java script code is running in your Java Virtual Machine or Dalvik Virtual Machine or whatever iOS use.
So here is the problem how to run JavaScript code in Android Machine (iOS machine),
1) Use WebView, but WebView is slow, there is a lot going on in a WebView, so much heavy lifting is done for you by the Android/IOS Machine to run Web Pages in your application. Page loads slowly, scrolling jerks and what not. That's why Cordova and PhoneGap apps don't work well.
2) We don't need WebView right, we need light-weight JavaScript compiler(interpreters) which can compile only a set of JS instructions not all of them. A program which targets only core JavaScript and read new defined XML/ReactNative tags. React-Native tags (Image, FlatList, Text etc) are converted on JS side and converted to JS methods calls not on Android/IOS side.
Read: https://reactjs.org/docs/react-without-jsx.html
JSX is first converted to JS first.
3) Here, JavaScript-Virtual Machine comes into play which is completely different from JVM or DVM. And can run on JVM or DVM.
React Native uses : JavaScriptCore
Read: https://www.raywenderlich.com/1227-javascriptcore-tutorial-for-ios-getting-started (This is for IOS)
Here is one and open source for you to look around
https://github.com/LiquidPlayer/LiquidCore: This is even contains a file system, react-native does not.
Note: Same idea FB used for NodeJs = backend JavaScript.
4) JS-Bundle: So now you can run JS code in your application, but how do you ship it. You will create one file i.e merge of the all the files and library files into one and call it JS-Bundle.
Simple command for Android
node node_modules/react-native/local-cli/cli.js bundle --entry-file index.js --platform android --bundle-output ../jsbundle/index.android.jsbundle --assets-dest ../jsbundle/res
5) JS-Bridge: Like the name provides bridge methods and components to communicate JavaScript and Native-Code(Android Java). How do they communicate, like everything else in React-Native, using JSON. JSON commands are sent to UiManager in native code to create UI on an asynchronous thread, which adds these commands into MessageQueue and process them.
Read: https://hackernoon.com/understanding-react-native-bridge-concept-e9526066ddb8
Also Read : https://tadeuzagallo.com/blog/react-native-bridge/
6) Threads:
JS-Thread : Handles UI commands as explained earlier. JS thread is
created as soon you invoke React-Native view from Android Code (Starting React Activity) and handles every view create or change command from React Native.
Native-Thread(Main Thread): Take press or touch events and pass them to JS-VM,
JS-VM passes them to your code, if success , process them and View change events are passed to your JS-Thread.
Async-Threads Now I don't have much idea about how do you create threads inside your JS/JSX code. Maybe it's possible but before it was not.
So for a JS point view your writing JS code that will run on light weight browser that is ReactView.
Read: https://www.codementor.io/#saketkumar95/how-react-native-works-mhjo4k6f3