At the top of my new react native app some boilerplate code is created
export default class App extends Component < {} > {
render() {
...
}
}
Within the Learn the Basics webpage of the React Native Documentation there is a section on Component. Within this section it mentions
A component can be pretty simple - the only thing that's required is a
render function...
I can't see in the API list an entry for Component. I presume this Component has the same idea as Object in Java as the base class for everything.
Java's Object class provides some methods such as toString().
I would like to know :
Is my presumption correct?
Is there a weblink to documentation somewhere that details the full
api for Component?
What else provided by react native, that isn't my own custom code, can be put inside my App
class?
You can read about React Components here. React-Native utilizes React architecture.
Component is a module of your app that has a particular functionality. On the left sidebar here you can see a section called "Components" These are the default React-Native components. You can create other components, needed in your app by using those components. Examples of how the components could look or be created are components of Expo SDK and React-Native-Elements component library.
Through this link you can view all of React-Native and Expo components on your device using Expo app: https://expo.io/#community/native-component-list
Your custom components / components of other libraries that you would like to render (put them in return statement, wrapped with parenthesis, like return (<Text>Hello World</Text>);.
Plus anything that is related to rendering your screen could also be put inside the render method, but outside the return statement. For example, state / props destructuring, conditional rendering (if something is true - show this view, else show this view) and so forth.
Related
I'm currently working on a sample application to learn Kotlin/Js with the react library. When using the normal JSX syntax, a component can be set to be triggered when a specific URL hits using the BrowserRouter & Route API like below.
Main Component
Navigation Component as directed like in this youtube video
When attempting the above code in Kotlin, it resembles something like the screenshot below using the KotlinDSL
The main function where the component is rendered is shown below
However, that creates an Uncaught Error Exception like the one below
One of the reasons its also so difficult to debug is because my source maps dont work and hence most of my debugging errors are actually in Javascript. But anyways after searching up the javascript error, I found this article about the new Router update that disallows adding components as children.
As a result I tried to pass in the components through the element prop but there seems to be some incompatibility with them.
the element prop accepts an optional ReactNode? and I cant seem to convert my Function Component of type props to a ReactNode. When I try to pass in an optional ReactElement? by calling the create method, I also get an error.
I have been struggling with the Kotlin Documentation and can't seem to find enough examples of react-router implemented.
Can anyone help me out with how to pass in a Function COmponent into the element prop for the React Router?
I wish to use Algolia to setup InstantSearch in my React Native project. I am using this tutorial to learn the basics.
It appears in their RefinementList and InfiniteHits components there is a parameter: refine. This parameter seems to play a key role in the functionality of this tutorial's app.
Where can I get an example of how this refine() method would look like?
Please help me with some resources. An explanation of this refine() method would also help.
Thanks!
I think there's a typo in the documentation at the time of this writing (for which I opened a pull request), and the name of the actual prop is refineNext.
The documented InfiniteHits example from the React Native guide uses a connector, which is a lower-level abstraction allowing users to fully control the UI. This is what allows you to use React Native code for the UI while having access to the InfiniteHits data and logic. You can read more about the connectInfiniteHits connector in the documentation.
The provided refineNext function lets you load more results. It doesn't take any arguments, all you need to do is call it whenever you want to load more results from Algolia. In the example, it's being used in the onEndReached callback of React Native's FlatList component, whenever the hasMore provided prop is true. This allows loading more results once when the scroll position gets within onEndReachedThreshold of the rendered content.
I'm using the react-instantsearch module on a React Native app. I'm using it as a controlled component, passing in a searchState like so:
<InstantSearch
appId='something'
apiKey='somethingElse'
indexName='index'
searchState={this.props.algoliaSearchState}
>
When I change the category (hierarchicalMenu) or location (aroundLatLng), this works fine, but when I change the query it has no effect on the hits that I get.
I can see that the query is being passed in (both by logging, and in react-native devtools:
Any ideas what could be going wrong here?
For a refinement to be applied, it needs to be present inside the search state and have a corresponding widget mounted.
For hierarchicalMenu it's HierarchicalMenu, for aroundLatLng it's Configure and for query it's SearchBox.
If you don't want any rendering for a widget just create a VirtualWidget. But for its refinement to be applied, it should be mounted.
I started using Mobx as state management for my react native app.
I noticed that few components render method is being called more than once. I understand its because one of the observable is modified or computed value is used. Mobx documentation mentions whyrun method to get a hint of why a particular method was run when the observable state is modified. However I did not find any reference to how to use it in react-native to find why the component render was triggered?
Did anyone use whyrun feature in react-native with Mobx?
You can import whyRun with import { whyRun } from 'mobx' and use it like you would use in a normal web project. Here are all the exports from MobX that shows the whyRun export:
MobX Exports
Hope that helps!
I am working on swipeListView in react native and they have line which state
If you are using the standalone you can just keep a ref to the component and call closeRow() on that ref.
But how do I create a ref and and how do I call it.
and also react native claims not to use the ref much and why is it so.
Not sure about React Native but here's how you create ref's in a React component.
<Component
ref={instance => {
this.componentReference = instance;
}}
/>
//Once you create a ref, you can access it in any of your function using this.ref (Like here it would be this.componentReference).
To answer your 2nd question, refs are considered a bad practice because they are nothing but a workaround to directly access your DOM element. React wants you to avoid direct DOM manipulations since you essentially loose the benefits and speed of React virtual DOM and your state gets cluttered since you directly manipulate your DOM.