Is it possible to pass a javascript function from React Native onto iOS Native components such as a UIButton and execute there?
It is possible, but using events and not by sending JS to native components. Check out react-native docs for detailed information, but generally:
React Native enables you to perform cross-language function calls. You
can execute custom native code from JS and vice versa. Unfortunately,
depending on the side we are working on, we achieve the same goal in
different ways. For native - we use events mechanism to schedule an
execution of a handler function in JS, while for React Native we
directly call methods exported by native modules.
Related
I am not able to use google.maps.geometry.poly.isLocationOnEdge() in my react native project. Is there any other way to check whether a point lies on a route which I can use to react native?
I recently came across this problem while using react-native-maps.
You can use isPointInLine(point, lineStart, lineEnd) method by using geolib JS package. This package has many other useful methods.
I'm trying to understand how I can do a signature capture in React Native. My App is created with create-react-native-app and Expo and I'd prefer to not have to eject the app to get this functionality to work.
Would it be possible to wrap something like this in a webview? https://github.com/szimek/signature_pad
I've also looked at this project, https://github.com/RepairShopr/react-native-signature-capture but it requires me to eject the app and use react-native link.
Looking for any advice or suggestions on how to implement this feature while keeping my project as straightforward as possible (ideally, using create-react-native-app, but if this isn't possible could someone please explain to me why?)
The way React Native works is that each component available in React Native maps to a native component in the underlying platform.
ie. a <Image /> is an ImageView in Android and a UIImageView.h in iOS.
The Javascript code itself runs in a Javascript thread on each platform and as you use Components in React Native, there's a translation layer that passes information from JS into the React Native bridge that then results in corresponding native components being created.
By default, React Native has included the following components: https://facebook.github.io/react-native/docs/components-and-apis.html#basic-components which means that only those components come out-of-the-box in React Native. If you want other components, then you have 2 options, either create a "composite" component in which your JS component is written into other JS components or, if your feature needs a native component not yet exposed by React Native, write your own "native" component to expose certain native functionality to your React Native code.
The way Expo works is that they have wrapped React Native and a handful of 3rd party components and built it within their application. The reason why you can't use a 3rd party native component they don't support is because when that component is used, the app itself doesn't have translation code to go from JS to a native Android/iOS view.
So, to do what you're asking, you'd need to find either a "native" drawing component that Expo has included in their platform/app. OR you need to find a "composite" drawing component that is built with other default React Native components (or other components Expo supports).
ie. On Android, I might build this with a Canvas view, but from what I can tell React Native doesn't support that object natively, so I would probably write this myself, etc.
It's hard for Expo to support every 3rd party "native" component out there because React Native is open source and it iterates so fast that most community-built components aren't always up to date or they might conflict with one another.
I am using react-native-signature-capture.
Working properly on both Android and iOS.
I know it's been a while, but there is an interesting article here: https://blog.expo.io/drawing-signatures-with-expo-25d1629ca1ac
Wait, but how?
Using “expo-pixi”, you can add a component that lets you choose your brush’s color, thickness, and opacity. Then when your user lifts her finger, you get a callback. From there you can take a screenshot of the transparent view or get the raw point data if that’s what you’re looking for.
Problem
I'm integrating React Native into an existing Android app (ie. making a hybrid app). I've created an Activity to host a React Native view. This works fine.
Now, I need to pass structured data from native into React Native. Represented as JSON, it looks something like this:
{
"landscape": ["http://example.com/1.jpg", "http://example.com/2.jpg"],
"portrait": ["http://example.com/3.jpg", "http://example.com/4.jpg"]
}
Given the context I describe how can I make this data available as props inside of the React Native app?
I see that this is an initialProperties argument available, but it seems to accept a Bundle, which as far as I can tell (Android newbie here) only accepts scalar values.
One option I am considering
Create JSON object in Java
Convert to a string
Add to Bundle and pass into initialProperties
Ingest as JSON and deserialize in React Native app
... but this seems hackish and requires me to add special code for Android that was not required for iOS.
Alternatives?
Is there a straightforward approach that I am missing?
Have you tried passing an array of strings into the Bundle?
bundle.putStringArray("landscape",yourArrayOfStrings]);
I notice from calling-react-native-functions-from-native-events that I could call js function or event with defined prop in native side
RCT_EXPORT_VIEW_PROPERTY(onChange, RCTBubblingEventBlock)
but how could I call js function without any defined in native side?
for example, if I wrap my project as sdk which be embedded in others'app, and I want to dynamic add new method in js side without modify any sdk native code, so the app will directly call changed logic without update sdk package framework after hotfix.
how should I implement it?
thanks for your time,
regards.
The official documentation for React Native explains how to add React Native views to existing native applications. However, it does not explain how to run React Native code written in JavaScript from a native application, without having to display any React Native component. Does the framework provide a way to do this?
I think reason being, R-N works on top of Native components and not other way round. I have not come across anything that you are looking.